Seminar #72 from Online Seminars for Municipal Arborists – January / February 2017
Sections Go directly to the section by clicking on the title below
Sections Go directly to the section by clicking on the title below
Note: Click on green text in each section for more information and photos.
A Solution to Global Warming
By Len Phillips
One of the best ways to deal with global warming is to plant trees. Better still, plant trees that will be tolerant of the rising temperatures, so they will survive when other trees may not. Most arborists are familiar with the U.S. Department of Agriculture's Plant Hardiness Zone Map. By using the map to find the zone where you work, you will be able to determine which trees will "winter over" in your city and survive for many years.
A heat zone map indicates the average number of days each year that a given region experiences "heat days" or temperatures over 86° F (30° C). That is the point at which plants begin suffering physiological damage from heat. The zones range from Zone 1 (Canada with less than one heat day) to Zone 12 (Florida and Texas with more than 210 heat days). Heat damage can first appear in many different parts of the tree: The flower may wither, or the leaves may droop, or the tree may become more attractive to insects, or chlorophyll may disappear so that leaves appear white or brown, or the roots may cease growing. Tree death from heat is slow and lingering.
As expected there are several species of trees that will tolerate heat, but there are now many new cultivars or introductions that have been selected for their heat tolerance in addition to other desirable features. Keep in mind that although these trees are heat tolerant, that does not mean that they are also resistant to disease and pest problems or other abiotic conditions. So when you are selecting a tree for planting, make sure you plant the right tree in the right spot, for the right reason.
Heat Tolerant Species
The following is a list of species that are tolerant of urban heat.
Botanical Name Trade Name Hardiness Zone Heat Zone
Acer buergerianum Trident Maple 5 – 9 9 - 5 Photo
Acer campestre Hedge Maple 5 – 8* 8 - 4 Photo
Acer rubrum Red Maple 3 – 9 8 - 1 Photo
Catalpa speciosa Catalpa 4 – 8 8 - 1 Photo
Cedrus spp. Cedar 5 – 9* 9 - 6 Photo
Celtis occidentalis Hackberry 2 – 9 9 - 1 Photo
Cryptomeria japonica Japanese Cryptomeria 5 – 9 9 - 4 Photo
Eucommia ulmoides Hardy Rubber Tree 4 – 7 7 - 1 Photo
Ginkgo biloba Ginkgo – male cultivars 3 – 9 9 - 3 Photo
Juniperus virginiana Eastern Redcedar 2 – 9 9 - 1 Photo
Lagerstroemia spp. Crape Myrtle 7 – 9* 12 - 9 Photo
Pinus spp. Pine 2 – 9* 8 - 1 Photo
Pistacia chinensis Chinese Pistache 6 – 9 9 - 6 Photo
Quercus acutissima Sawtooth Oak 5 – 9 8 - 1 Photo
Quercus phellos Willow Oak 5 – 9 9 - 3 Photo
Quercus rubra Red Oak 4 – 8 9 - 5 Photo
Sophora japonica Japanese Pagodatree 4 – 8 9 - 5 Photo
Tilia cordata Littleleaf Linden 3 – 7 8 - 1 Photo
Tilia tomentosa Silver Linden 4 – 7 9 - 1 Photo
Ulmus parvifolia Lacebark Elm 4 – 9 9 - 1 Photo
Zelkova serrata Japanese Zelkova 5 – 8 9 - 5 Photo
* Zone range depends on the species selected, as some are more heat tolerant than others.
Heat Tolerant Cultivars
This second list contains heat tolerant cultivars selected from species that are not noted for being heat tolerant. These cultivars were selected for their excellent tolerance to heat within the climatic range of the species.
Botanical Name Trade Name Hardiness Zone Heat Zone Photo
Acer ginnala 'JFS-UGA' Red November™ Maple 2 – 8 7 – 1 Photo
Acer platanoides ‘Summershade’ Summershade Norway Maple 3 – 8 7 – 1 Photo
Acer saccharum 'Autumn Splendor' Autumn Splendor Sugar Maple 5 – 9 8 – 1 Photo
A. s. ‘Bailsta’ Fall Fiesta® Sugar Maple 4 – 8 8 – 1 Photo
A. s. ‘Green Mountain’ Green Mountain® Sugar Maple 4 – 8 8 – 1 Photo
A. s. ‘JFS-Caddo2’ Flashfire® Sugar Maple 5 – 9 8 – 1 Photo
A. s. 'John Pair' John Pair Sugar Maple 5 – 9 8 – 1 Photo
A. s. ‘Legacy’ Legacy’® Sugar Maple 4 – 8 8 – 1 Photo
A. s. 'Morton' Crescendo™ Sugar Maple 5 – 9 8 – 1 Photo
A. s. 'Reba' Belle Tower™ Sugar Maple 5 – 8 8 – 1 Photo
Acer x freemanii 'Jeffersred' Autumn Blaze® Maple 3 – 8 8 – 1 Photo
Acer truncatum x plat. ‘JFS-KW202’ Crimson Sunset® Maple 4 – 8 8 – 1 Photo
Betula nigra 'BNMTF' Dura-Heat River Birch 6 – 9 11 – 1 Photo
Betula platyphylla ‘Whitespire’ Whitespire White Birch 4 – 9 7 – 5 Photo
Carpinus betulus JFS-KW1CB’ Emerald Avenue® Hornbeam 4 – 7 8 – 1 Photo
Celtis 'Magnifica' Magnifica Hackberry 2 – 9 9 – 1 Photo
Fraxinus pennsylvanica 'Cimmzam' Cimmaron™ Ash ** 3 – 9 9 – 1
F.p. 'Georgia Gem™' Georgia Gem Ash® ** 3 – 9 9 – 1 Photo
F.p. 'Urbdell' Urbanite™ Ash ** 3 – 9 9 – 1 Photo
Gymnocladus dioicus ‘Espresso-JFS’ Espresso™ Kentucky Coffeetree 3 – 8 9 – 2 Photo
Koelreuteria paniculata 'JFS-Sunleaf' Summerburst Goldenrain Tree 5 – 9 9 – 1 Photo
Ulmus propinqua 'JFS-Bieberich Emerald Sunshine Elm 5 – 9 9 – 1 Photo
** non-EAB areas only
I hope you find these lists useful. Plant wisely and with the future in mind.
Sources
· Appleton, Bonnie, et. al. “Trees for hot sites”, Virginia Cooperative Extension, Publication 430-024, 2015
· J Frank Schmidt Reference Guide, 2014.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
One of the best ways to deal with global warming is to plant trees. Better still, plant trees that will be tolerant of the rising temperatures, so they will survive when other trees may not. Most arborists are familiar with the U.S. Department of Agriculture's Plant Hardiness Zone Map. By using the map to find the zone where you work, you will be able to determine which trees will "winter over" in your city and survive for many years.
A heat zone map indicates the average number of days each year that a given region experiences "heat days" or temperatures over 86° F (30° C). That is the point at which plants begin suffering physiological damage from heat. The zones range from Zone 1 (Canada with less than one heat day) to Zone 12 (Florida and Texas with more than 210 heat days). Heat damage can first appear in many different parts of the tree: The flower may wither, or the leaves may droop, or the tree may become more attractive to insects, or chlorophyll may disappear so that leaves appear white or brown, or the roots may cease growing. Tree death from heat is slow and lingering.
As expected there are several species of trees that will tolerate heat, but there are now many new cultivars or introductions that have been selected for their heat tolerance in addition to other desirable features. Keep in mind that although these trees are heat tolerant, that does not mean that they are also resistant to disease and pest problems or other abiotic conditions. So when you are selecting a tree for planting, make sure you plant the right tree in the right spot, for the right reason.
Heat Tolerant Species
The following is a list of species that are tolerant of urban heat.
Botanical Name Trade Name Hardiness Zone Heat Zone
Acer buergerianum Trident Maple 5 – 9 9 - 5 Photo
Acer campestre Hedge Maple 5 – 8* 8 - 4 Photo
Acer rubrum Red Maple 3 – 9 8 - 1 Photo
Catalpa speciosa Catalpa 4 – 8 8 - 1 Photo
Cedrus spp. Cedar 5 – 9* 9 - 6 Photo
Celtis occidentalis Hackberry 2 – 9 9 - 1 Photo
Cryptomeria japonica Japanese Cryptomeria 5 – 9 9 - 4 Photo
Eucommia ulmoides Hardy Rubber Tree 4 – 7 7 - 1 Photo
Ginkgo biloba Ginkgo – male cultivars 3 – 9 9 - 3 Photo
Juniperus virginiana Eastern Redcedar 2 – 9 9 - 1 Photo
Lagerstroemia spp. Crape Myrtle 7 – 9* 12 - 9 Photo
Pinus spp. Pine 2 – 9* 8 - 1 Photo
Pistacia chinensis Chinese Pistache 6 – 9 9 - 6 Photo
Quercus acutissima Sawtooth Oak 5 – 9 8 - 1 Photo
Quercus phellos Willow Oak 5 – 9 9 - 3 Photo
Quercus rubra Red Oak 4 – 8 9 - 5 Photo
Sophora japonica Japanese Pagodatree 4 – 8 9 - 5 Photo
Tilia cordata Littleleaf Linden 3 – 7 8 - 1 Photo
Tilia tomentosa Silver Linden 4 – 7 9 - 1 Photo
Ulmus parvifolia Lacebark Elm 4 – 9 9 - 1 Photo
Zelkova serrata Japanese Zelkova 5 – 8 9 - 5 Photo
* Zone range depends on the species selected, as some are more heat tolerant than others.
Heat Tolerant Cultivars
This second list contains heat tolerant cultivars selected from species that are not noted for being heat tolerant. These cultivars were selected for their excellent tolerance to heat within the climatic range of the species.
Botanical Name Trade Name Hardiness Zone Heat Zone Photo
Acer ginnala 'JFS-UGA' Red November™ Maple 2 – 8 7 – 1 Photo
Acer platanoides ‘Summershade’ Summershade Norway Maple 3 – 8 7 – 1 Photo
Acer saccharum 'Autumn Splendor' Autumn Splendor Sugar Maple 5 – 9 8 – 1 Photo
A. s. ‘Bailsta’ Fall Fiesta® Sugar Maple 4 – 8 8 – 1 Photo
A. s. ‘Green Mountain’ Green Mountain® Sugar Maple 4 – 8 8 – 1 Photo
A. s. ‘JFS-Caddo2’ Flashfire® Sugar Maple 5 – 9 8 – 1 Photo
A. s. 'John Pair' John Pair Sugar Maple 5 – 9 8 – 1 Photo
A. s. ‘Legacy’ Legacy’® Sugar Maple 4 – 8 8 – 1 Photo
A. s. 'Morton' Crescendo™ Sugar Maple 5 – 9 8 – 1 Photo
A. s. 'Reba' Belle Tower™ Sugar Maple 5 – 8 8 – 1 Photo
Acer x freemanii 'Jeffersred' Autumn Blaze® Maple 3 – 8 8 – 1 Photo
Acer truncatum x plat. ‘JFS-KW202’ Crimson Sunset® Maple 4 – 8 8 – 1 Photo
Betula nigra 'BNMTF' Dura-Heat River Birch 6 – 9 11 – 1 Photo
Betula platyphylla ‘Whitespire’ Whitespire White Birch 4 – 9 7 – 5 Photo
Carpinus betulus JFS-KW1CB’ Emerald Avenue® Hornbeam 4 – 7 8 – 1 Photo
Celtis 'Magnifica' Magnifica Hackberry 2 – 9 9 – 1 Photo
Fraxinus pennsylvanica 'Cimmzam' Cimmaron™ Ash ** 3 – 9 9 – 1
F.p. 'Georgia Gem™' Georgia Gem Ash® ** 3 – 9 9 – 1 Photo
F.p. 'Urbdell' Urbanite™ Ash ** 3 – 9 9 – 1 Photo
Gymnocladus dioicus ‘Espresso-JFS’ Espresso™ Kentucky Coffeetree 3 – 8 9 – 2 Photo
Koelreuteria paniculata 'JFS-Sunleaf' Summerburst Goldenrain Tree 5 – 9 9 – 1 Photo
Ulmus propinqua 'JFS-Bieberich Emerald Sunshine Elm 5 – 9 9 – 1 Photo
** non-EAB areas only
I hope you find these lists useful. Plant wisely and with the future in mind.
Sources
· Appleton, Bonnie, et. al. “Trees for hot sites”, Virginia Cooperative Extension, Publication 430-024, 2015
· J Frank Schmidt Reference Guide, 2014.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Paving Around Street Trees
By Len Phillips and Gordon Mann
Edited by RW Gibney RLA ISA
Municipal arborists around the country are looking at options for improving the aesthetics, reducing maintenance, and discouraging compaction of the soil surrounding downtown trees planted next to the concrete sidewalks. For many years, metal tree grates were the standard option, but they require routine maintenance, and are rather expensive to purchase and enlarge as the tree grows bigger.
In recent years, some new pavement products have been used to replace these metal tree grates. These products have been installed around sidewalk trees in several downtown cities. The pavements vary from 100% soil mix, to stone aggregate, and to recycled rubber chips, all in varying proportions of mix. All of these options eliminate the metal tree grate and frame footing.
Flexible Pavement Option - Photo
A flexible surface is created around the tree by spreading rubber chips or small paving stones that have been bonded together with a high-quality clear resin or urethane binding agent, on the soil surface. It results in a flexible, porous surfacing material, that is resistant to cracking. The products are mixed on-site and applied to coat the particles prior to laying the material on the ground. The material is easily cut to enlarge the hole around the trunk as the tree grows. The pavement material is usually not re-usable.
Porous Paving
The first product to be discussed is called porous pavement - see Photo. It is a fully permeable paving product which allows water to freely drain through the surface. The porous pavement's non-skid, 50% rubber content and 50% stone aggregate surface along with a hard urethane binder ensures good traction even when wet, lessening the chance of slip and fall accidents. In addition, the rubber content allows the product to flex with trunk growth, or with any roots that come to the surface. This flexibility resists cracking and heaving commonly found with concrete sidewalks. The porous and flexible rubber content prevents soil compaction but allows air and surface water penetration, which encourages the tree roots to grow deeply. The rubber in these pavements is made with tires diverted from landfills. Porous pavement uses scrap tires to create a 5 x 5 feet (140 cm sq. 5 cm. thick) square of 2″ thick porous pavement. The product comes in several custom colors such as gray-black, tan-black, brown-black, cypress-black, red-black, brown-tan, green-brown and blue-gray. The surface is easily cut to enlarge the hole around the trunk as the tree grows - see Photo.
The most difficult part of the entire installation is the clean-up of the tools. However, if vegetable oil is coated over all the tools and equipment before use, the cleanup with bio-diesel fuel and a stiff bristle brush is much easier. The binder is moisture cured, so if the weather is humid the product will cure more quickly. Generally this product cures within 24 hours after being poured.
Soft Paving
A soft formulation of porous pavement is made with 100% recycled rubber chips, no stone, and held together with a soft binder. Landscape architects and recreation specialists specify this product to provide a more impact-absorbing surface for applications such as playgrounds and pool pavements, while arborists are starting to specify this product to be used for trees surrounded by sidewalks.
· At 1″ (2.5 cm) thick, the product can be used to overlay existing concrete, asphalt, metal surfaces and wood.
· At 1½″ (4 cm) thick, the product can be used for bike paths, patios, trails, golf cart paths and any other
pedestrian traffic.
· At 2″ (5 cm) thick, the product can be used for low speed car and truck traffic.
Rubber Panels
Several companies make rubber sidewalk panels made from recycled tires. This product is firm enough to walk on or roller blade and skate board over. However, the panels need a solid edge piece of either plastic or steel angle to hold them inward like interlocking pavers which the concrete sidewalk surrounding the tree planting pit provides. Unfortunately the rubber edges next to the tree trunk may curl up over time. The material has to be cut with a small power saw to enlarge the space around the tree's flare. The product can be pulled up and re-used for other trees.
Plastic Panels
Another sidewalk product is recycled plastic interlocking panels. These panels are made from recycled tires and plastic. This product is firm enough to walk on or roller blade and skate board over. The panel size is the same as rubber panels of 2’ X 2.5’ (60 X 75 cm) and requires a larger opening to install. The panels are permeable between the seams. The panels are laid over ¾ inch (2 cm) aggregate and staked to the ground around the outside edge of the panels. The panels can be cut with a small power saw to enlarge the trunk opening. This product can also be re-used on other trees.
Resin Bonded Surfacing
This is a product that consists of viscous, high-strength resins that flow around the aggregate pieces and glues them together. The high strength resins are clear, and as they coat decorative aggregate, they bring out the shine and luster of the aggregate, improving the appearance. The site is graded out, the aggregates are mixed with the polymer binder, and spread out over the soil and a geotextile or thin gravel base around the tree pit to create a level area. A spacer or form is needed to create space around the tree trunk.
Polymer Binding Agent
Some resin bonded surfacing products as well as polymer binding agents can be put over other paving materials using a thin layer of resin applied to a solid surface and the aggregate scattered on top. This method creates a surface that is impermeable. The result is a resin bound surface that is more durable and requires less maintenance. However, these options are not suitable for the base of trees due to the need for a permeable surface.
Hoggin
In the UK, there is a soil process called hoggin that is used to create a soft-looking but hard-wearing path of soil - see Photo. It is also called "dug gravel" or "pit-run gravel". Hoggin contains a mix of sand and gravel and at least 30% clay or fine dirt that acts as a binder. Hoggin should generally contain no particles larger than 1-1/2 in.(40 mm) with all the different sizes of particles evenly mixed. Hoggin is used as a road or sidewalk base as well as for a surface material within a tree pit, next to the sidewalk. This material, when compacted makes a very stable surface and seldom needs raking.
Hoggin is usually applied as a permeable surface layer, over compacted gravel or crushed stone. It should be spread evenly over a suitable base and compacted with a 9 ton (8 metric tonne) vibrating roller to the required thickness. Water must be added at the time of rolling to bring the clay particles to the surface to seal all the stone products. If the thickness has to be greater than 3 inches (80mm) it should be laid and compacted in successive layers not exceeding 3 inches. Usually a depth of around 3-4 inches (80-100mm) after compaction will be suitable for pedestrian and tree use. The use of a vibrating roller may prohibit the use of hoggin for trees in small sidewalk openings if the sidewalk is not hoggin. However, in park settings or trees beside hoggin sidewalks, it might work out very well. It is important that the hoggin does not sit in water. Edge restraints are essential to keep the hoggin from moving towards the tree or beyond the edge during installation. The edge restraint can be moved and the product re-compacted as the tree grows.
Interlocking Pavers
Interlocking pavers can be used around the base of trees. A geotextile fabric is placed over the soil, then a layer of rock to be compacted, then geotextile and finally the layer of sand. The pavers are set in the sand and the pavers and rock are permeable. The pavers need an edge restraint which can be the sidewalk, an angle steel material, plastic, or wood form. As the tree grows, the edge restraint is removed, the size enlarged and the pavers can be re-used at other trees.
Benefits
Any of these porous pavements minimize the volume of stormwater run-off compared to a concrete, or bituminous surface. The porous pavements are resistant to damage from oil, chlorine, ozone, UV rays, muratic acid, gasoline, diesel, and transmission fluid, salt water, and many other hostile materials. They all are also resistant to snow plow damage on the surface. All the pavements mentioned here are ADA-compliant surface treatments.
Installation
With all these alternatives, the site has to be prepared by grading, and then installing 2 inches (5 cm) of ½ inch (1.3 cm) stone, lightly compacted in place, on top of the root ball. The pavement material is then placed on top of the stone.
Maintenance
All the materials need to be swept or power washed at least twice a year to avoid the buildup of debris and prevent the growth of moss or algae. However, since most cities mechanically sweep their sidewalks periodically, the tree surfaces can be swept at the same time.
Metal Tree Grates
Metal tree grates have previously been the product of choice for urban area trees. They provide a bridged tree guard and open space around the tree. The challenges that have surfaced with tree grates include:
· the cost of metal grates is generally higher than any of the options indicated above. Costs do vary depending on quantity and size of the opening.
· the footing required to support the tree grate frame is usually a thicker section than the adjacent walkway material. The footing is the most likely part of the system to be affected by tree root growth.
· the cost to enlarge the tree grate hole can be expensive, and requires a cutting torch or large steel cutting saw. The torch should be used very carefully around the tree to avoid tissue damage.
· a benefit of tree grates is they can be re-used, and if a community has a large inventory of grates, they can be swapped as the trees grow, and cutting may not be needed.
Case Studies
In its continuing effort to make its downtown more welcoming, and to support its sustainability initiatives, Grand Rapids, MI is completing the replacement of 750 old iron tree grates with a porous pavement. The first phase of the project was completed in September 2014 when the city replaced 250 cracked and broken grates that presented the most serious tripping hazard in the three square miles of the city's downtown area. An additional 500 grates were replaced in 2015, to finish the project. To leave space around the tree trunk, cardboard tubes were made and cut into 6”- 8” lengths and used as sleeves around the tree trunk prior to adding the pavement. The next day, the material had cured and the tubes were removed. The cost of the product worked out to be about US $400 compared to $800 to $1200 for the previous iron grates. The cost of maintaining tree grates and cutting the openings larger as the trees grow can range in expense from $100 to $200 per tree. The cutting of the porous pavement should require less effort and time than cutting cast iron grates, and can be done with a saw cutting through the depth of the pavement.
Redwood City, CA used a different product than any mentioned here, and that was poured in place rubber for sidewalks. They tried this at several locations, however, the material was too soft to walk on and being a one-piece section, they were unable to maintain the roots when the roots grew larger under the rubber material. If the City has to tear the material out and replace it, it really isn’t sustainable, unless they can recycle the material for re-use at a reasonable price.
Redwood City also used interlocking pavers around some trees. The pavers required a strong form on the tree side to hold the pavers in place, and the maintenance to keep the pavers from sagging was very costly. They also used tree grates, and the initial grate sizes that were less expensive were failing as roots raised the grate frame footings. The project managers did not want to invest in the more expensive larger grates to
create more space between the tree and the permanent sidewalk.
Boxford, MA used living mulch around its trees. This is very appropriate for a wealthy rural community where aesthetics are very important. More on the subject of living mulches will be coming in the next Seminar.
Specifications
There will need to be clear specifications and a strength analysis of the materials to satisfy most civil engineers before they will include the materials in a walkway repair or walkway design, especially if the potential for vehicle travel over the surface is likely.
Challenges
No system is perfect, and the challenge with poured in place porous pavers is that they are not modular. On any product, the opening around the tree will have to be enlarged or cut to make the space bigger over time as the tree grows. The most practical method to cut the openings larger for each product was mentioned in the product description, and can be performed by in-house crews or contractors. If the opening is too large at planting time, it can be a risk to walkway users. If the planting opening is not large enough for the mature size of the tree, the porous pavement will be lifted similar to typical sidewalk lifting observed when trees are growing too close to concrete or asphalt.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips and Gordon Mann
Edited by RW Gibney RLA ISA
Municipal arborists around the country are looking at options for improving the aesthetics, reducing maintenance, and discouraging compaction of the soil surrounding downtown trees planted next to the concrete sidewalks. For many years, metal tree grates were the standard option, but they require routine maintenance, and are rather expensive to purchase and enlarge as the tree grows bigger.
In recent years, some new pavement products have been used to replace these metal tree grates. These products have been installed around sidewalk trees in several downtown cities. The pavements vary from 100% soil mix, to stone aggregate, and to recycled rubber chips, all in varying proportions of mix. All of these options eliminate the metal tree grate and frame footing.
Flexible Pavement Option - Photo
A flexible surface is created around the tree by spreading rubber chips or small paving stones that have been bonded together with a high-quality clear resin or urethane binding agent, on the soil surface. It results in a flexible, porous surfacing material, that is resistant to cracking. The products are mixed on-site and applied to coat the particles prior to laying the material on the ground. The material is easily cut to enlarge the hole around the trunk as the tree grows. The pavement material is usually not re-usable.
Porous Paving
The first product to be discussed is called porous pavement - see Photo. It is a fully permeable paving product which allows water to freely drain through the surface. The porous pavement's non-skid, 50% rubber content and 50% stone aggregate surface along with a hard urethane binder ensures good traction even when wet, lessening the chance of slip and fall accidents. In addition, the rubber content allows the product to flex with trunk growth, or with any roots that come to the surface. This flexibility resists cracking and heaving commonly found with concrete sidewalks. The porous and flexible rubber content prevents soil compaction but allows air and surface water penetration, which encourages the tree roots to grow deeply. The rubber in these pavements is made with tires diverted from landfills. Porous pavement uses scrap tires to create a 5 x 5 feet (140 cm sq. 5 cm. thick) square of 2″ thick porous pavement. The product comes in several custom colors such as gray-black, tan-black, brown-black, cypress-black, red-black, brown-tan, green-brown and blue-gray. The surface is easily cut to enlarge the hole around the trunk as the tree grows - see Photo.
The most difficult part of the entire installation is the clean-up of the tools. However, if vegetable oil is coated over all the tools and equipment before use, the cleanup with bio-diesel fuel and a stiff bristle brush is much easier. The binder is moisture cured, so if the weather is humid the product will cure more quickly. Generally this product cures within 24 hours after being poured.
Soft Paving
A soft formulation of porous pavement is made with 100% recycled rubber chips, no stone, and held together with a soft binder. Landscape architects and recreation specialists specify this product to provide a more impact-absorbing surface for applications such as playgrounds and pool pavements, while arborists are starting to specify this product to be used for trees surrounded by sidewalks.
· At 1″ (2.5 cm) thick, the product can be used to overlay existing concrete, asphalt, metal surfaces and wood.
· At 1½″ (4 cm) thick, the product can be used for bike paths, patios, trails, golf cart paths and any other
pedestrian traffic.
· At 2″ (5 cm) thick, the product can be used for low speed car and truck traffic.
Rubber Panels
Several companies make rubber sidewalk panels made from recycled tires. This product is firm enough to walk on or roller blade and skate board over. However, the panels need a solid edge piece of either plastic or steel angle to hold them inward like interlocking pavers which the concrete sidewalk surrounding the tree planting pit provides. Unfortunately the rubber edges next to the tree trunk may curl up over time. The material has to be cut with a small power saw to enlarge the space around the tree's flare. The product can be pulled up and re-used for other trees.
Plastic Panels
Another sidewalk product is recycled plastic interlocking panels. These panels are made from recycled tires and plastic. This product is firm enough to walk on or roller blade and skate board over. The panel size is the same as rubber panels of 2’ X 2.5’ (60 X 75 cm) and requires a larger opening to install. The panels are permeable between the seams. The panels are laid over ¾ inch (2 cm) aggregate and staked to the ground around the outside edge of the panels. The panels can be cut with a small power saw to enlarge the trunk opening. This product can also be re-used on other trees.
Resin Bonded Surfacing
This is a product that consists of viscous, high-strength resins that flow around the aggregate pieces and glues them together. The high strength resins are clear, and as they coat decorative aggregate, they bring out the shine and luster of the aggregate, improving the appearance. The site is graded out, the aggregates are mixed with the polymer binder, and spread out over the soil and a geotextile or thin gravel base around the tree pit to create a level area. A spacer or form is needed to create space around the tree trunk.
Polymer Binding Agent
Some resin bonded surfacing products as well as polymer binding agents can be put over other paving materials using a thin layer of resin applied to a solid surface and the aggregate scattered on top. This method creates a surface that is impermeable. The result is a resin bound surface that is more durable and requires less maintenance. However, these options are not suitable for the base of trees due to the need for a permeable surface.
Hoggin
In the UK, there is a soil process called hoggin that is used to create a soft-looking but hard-wearing path of soil - see Photo. It is also called "dug gravel" or "pit-run gravel". Hoggin contains a mix of sand and gravel and at least 30% clay or fine dirt that acts as a binder. Hoggin should generally contain no particles larger than 1-1/2 in.(40 mm) with all the different sizes of particles evenly mixed. Hoggin is used as a road or sidewalk base as well as for a surface material within a tree pit, next to the sidewalk. This material, when compacted makes a very stable surface and seldom needs raking.
Hoggin is usually applied as a permeable surface layer, over compacted gravel or crushed stone. It should be spread evenly over a suitable base and compacted with a 9 ton (8 metric tonne) vibrating roller to the required thickness. Water must be added at the time of rolling to bring the clay particles to the surface to seal all the stone products. If the thickness has to be greater than 3 inches (80mm) it should be laid and compacted in successive layers not exceeding 3 inches. Usually a depth of around 3-4 inches (80-100mm) after compaction will be suitable for pedestrian and tree use. The use of a vibrating roller may prohibit the use of hoggin for trees in small sidewalk openings if the sidewalk is not hoggin. However, in park settings or trees beside hoggin sidewalks, it might work out very well. It is important that the hoggin does not sit in water. Edge restraints are essential to keep the hoggin from moving towards the tree or beyond the edge during installation. The edge restraint can be moved and the product re-compacted as the tree grows.
Interlocking Pavers
Interlocking pavers can be used around the base of trees. A geotextile fabric is placed over the soil, then a layer of rock to be compacted, then geotextile and finally the layer of sand. The pavers are set in the sand and the pavers and rock are permeable. The pavers need an edge restraint which can be the sidewalk, an angle steel material, plastic, or wood form. As the tree grows, the edge restraint is removed, the size enlarged and the pavers can be re-used at other trees.
Benefits
Any of these porous pavements minimize the volume of stormwater run-off compared to a concrete, or bituminous surface. The porous pavements are resistant to damage from oil, chlorine, ozone, UV rays, muratic acid, gasoline, diesel, and transmission fluid, salt water, and many other hostile materials. They all are also resistant to snow plow damage on the surface. All the pavements mentioned here are ADA-compliant surface treatments.
Installation
With all these alternatives, the site has to be prepared by grading, and then installing 2 inches (5 cm) of ½ inch (1.3 cm) stone, lightly compacted in place, on top of the root ball. The pavement material is then placed on top of the stone.
Maintenance
All the materials need to be swept or power washed at least twice a year to avoid the buildup of debris and prevent the growth of moss or algae. However, since most cities mechanically sweep their sidewalks periodically, the tree surfaces can be swept at the same time.
Metal Tree Grates
Metal tree grates have previously been the product of choice for urban area trees. They provide a bridged tree guard and open space around the tree. The challenges that have surfaced with tree grates include:
· the cost of metal grates is generally higher than any of the options indicated above. Costs do vary depending on quantity and size of the opening.
· the footing required to support the tree grate frame is usually a thicker section than the adjacent walkway material. The footing is the most likely part of the system to be affected by tree root growth.
· the cost to enlarge the tree grate hole can be expensive, and requires a cutting torch or large steel cutting saw. The torch should be used very carefully around the tree to avoid tissue damage.
· a benefit of tree grates is they can be re-used, and if a community has a large inventory of grates, they can be swapped as the trees grow, and cutting may not be needed.
Case Studies
In its continuing effort to make its downtown more welcoming, and to support its sustainability initiatives, Grand Rapids, MI is completing the replacement of 750 old iron tree grates with a porous pavement. The first phase of the project was completed in September 2014 when the city replaced 250 cracked and broken grates that presented the most serious tripping hazard in the three square miles of the city's downtown area. An additional 500 grates were replaced in 2015, to finish the project. To leave space around the tree trunk, cardboard tubes were made and cut into 6”- 8” lengths and used as sleeves around the tree trunk prior to adding the pavement. The next day, the material had cured and the tubes were removed. The cost of the product worked out to be about US $400 compared to $800 to $1200 for the previous iron grates. The cost of maintaining tree grates and cutting the openings larger as the trees grow can range in expense from $100 to $200 per tree. The cutting of the porous pavement should require less effort and time than cutting cast iron grates, and can be done with a saw cutting through the depth of the pavement.
Redwood City, CA used a different product than any mentioned here, and that was poured in place rubber for sidewalks. They tried this at several locations, however, the material was too soft to walk on and being a one-piece section, they were unable to maintain the roots when the roots grew larger under the rubber material. If the City has to tear the material out and replace it, it really isn’t sustainable, unless they can recycle the material for re-use at a reasonable price.
Redwood City also used interlocking pavers around some trees. The pavers required a strong form on the tree side to hold the pavers in place, and the maintenance to keep the pavers from sagging was very costly. They also used tree grates, and the initial grate sizes that were less expensive were failing as roots raised the grate frame footings. The project managers did not want to invest in the more expensive larger grates to
create more space between the tree and the permanent sidewalk.
Boxford, MA used living mulch around its trees. This is very appropriate for a wealthy rural community where aesthetics are very important. More on the subject of living mulches will be coming in the next Seminar.
Specifications
There will need to be clear specifications and a strength analysis of the materials to satisfy most civil engineers before they will include the materials in a walkway repair or walkway design, especially if the potential for vehicle travel over the surface is likely.
Challenges
No system is perfect, and the challenge with poured in place porous pavers is that they are not modular. On any product, the opening around the tree will have to be enlarged or cut to make the space bigger over time as the tree grows. The most practical method to cut the openings larger for each product was mentioned in the product description, and can be performed by in-house crews or contractors. If the opening is too large at planting time, it can be a risk to walkway users. If the planting opening is not large enough for the mature size of the tree, the porous pavement will be lifted similar to typical sidewalk lifting observed when trees are growing too close to concrete or asphalt.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Urban Tree of the Year 2017
Edited By Len Phillips
Chestnut Oak has been selected as the Society of Municipal Arborists, Urban Tree of the Year for 2017.
Botanical Name: Quercus prinus
Common Name: Chestnut Oak, Basket Oak, Rock Oak
Parentage: Native
Family: Fagaceae
Height: 50' - 70'
Spread: Varies considerably
Form: Rounded to pyramidal shape and dense
Bloom Period: Early to mid-March
Flower: 3" – 4" long catkins
Fruit: 1" long acorn, 3/4” wide, dark brown, cap covers 1/3 to ½ of the nut
Summer Foliage: Dark yellow green, grayish tomentulose underneath, look like chestnut leaves
Autumn Foliage: Orange yellow to yellow brown in the fall
Winter Color: Bark provides winter interest
Bark: Dark brown to black, more rich in tannin than any other oak, deeply furrowed, blocky bark
Habitat: East Coast
Culture: Tough, found on poor, dry, rocky, upland sites, adapts to any pH, full sun
Hardiness Zone: 4 – 8
Growth Rate: Moderate, up to 18 inches a year on wet and well-drained sites
Pest Resistance: Resistant to mildew and most major pests
Storm Resistance: Excellent
Salt Resistance: Good to excellent
Planting: B & B is best
Pruning: Needs minimal pruning except to raise lower branches
Propagating: Seed
Design Uses: Excellent for parks, golf courses and commercial areas, use as street tree only when space is available
Companions: Use with shrubs such as Taxus or groundcovers such as vinca
Photos: Full size tree
Leaves and acorn
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited By Len Phillips
Chestnut Oak has been selected as the Society of Municipal Arborists, Urban Tree of the Year for 2017.
Botanical Name: Quercus prinus
Common Name: Chestnut Oak, Basket Oak, Rock Oak
Parentage: Native
Family: Fagaceae
Height: 50' - 70'
Spread: Varies considerably
Form: Rounded to pyramidal shape and dense
Bloom Period: Early to mid-March
Flower: 3" – 4" long catkins
Fruit: 1" long acorn, 3/4” wide, dark brown, cap covers 1/3 to ½ of the nut
Summer Foliage: Dark yellow green, grayish tomentulose underneath, look like chestnut leaves
Autumn Foliage: Orange yellow to yellow brown in the fall
Winter Color: Bark provides winter interest
Bark: Dark brown to black, more rich in tannin than any other oak, deeply furrowed, blocky bark
Habitat: East Coast
Culture: Tough, found on poor, dry, rocky, upland sites, adapts to any pH, full sun
Hardiness Zone: 4 – 8
Growth Rate: Moderate, up to 18 inches a year on wet and well-drained sites
Pest Resistance: Resistant to mildew and most major pests
Storm Resistance: Excellent
Salt Resistance: Good to excellent
Planting: B & B is best
Pruning: Needs minimal pruning except to raise lower branches
Propagating: Seed
Design Uses: Excellent for parks, golf courses and commercial areas, use as street tree only when space is available
Companions: Use with shrubs such as Taxus or groundcovers such as vinca
Photos: Full size tree
Leaves and acorn
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Case Study
Tree Planting
Edited by Len Phillips
Blackheath Hill, Greenwich, is an area of southeast London, England, noted for its traditional pubs, quaint village, and an extensively large green space. In 2001, a street, sidewalk, and tree improvement project was undertaken at the main cross-roads in Blackheath Hill. When the tree was planted it was one of the first installations in the world utilizing a soil-support cell system that was designed to encourage tree root growth. See Photo
The concept was to provide a high-quality soil cell tree pit, limited in volume due to the close proximity of buildings, but capable of permitting vehicular traffic on the surface of the tree pit adjacent to one of the busiest routes into the city. The international engineering group involved in the design identified a planting location, but realized that without proper provision below ground, the tree would become an expensive failure.
The consultant designed a tree pit incorporating a tree planting system that provided soil cells to offer non-compacted soil volume for root growth, a tree pit irrigation/aeration system to provide the vital moisture and oxygen that every tree needs, and a system to direct roots away from paved surfaces and utilities and into the intended rooting zone.
The tree pit was designed to be 16 feet (5 meters) long by 3.5 ft (1m) wide by 3.5 ft (1m) deep which provided a 200 cubic ft (5 cubic m) area of excellent soil. The planting location was 12 ft (4m) from the nearest building, and the surface around the tree was continuous pavement with irrigation/aeration inlets set into the granite paving stone on the surface.
Having been directed downwards by a shallow root barrier product, to an appropriate level below the paved surface, the roots grew into the load bearing soil cells. The cells were intended in this instance to provide enough soil for the complete life of the tree. The tree's ultimate size had to be limited because of branch space constraints and also to protect the utilities and services surrounding the tree pit area. This type of tree pit is designed for constricted space applications above ground where it is not possible to provide large volume ‘complete life’ branch growth, and limited below ground soil cell structures due to lack of space not occupied with utilities and surface pavements.
Tree Pit Details & Installation
The outer perimeter of the tree pit was lined on three sides with a high-density polyethylene root barrier. The purpose of this was to contain roots within an intended area, while preventing roots from spreading laterally but allowing them to spread deeper. Within that perimeter, the load bearing soil cells were placed on two sides of the tree and filled with a sandy loam topsoil mix.
Compaction and drainage at the base of the tree pit were critical. In this instance, the tree pit was free-draining so no additional drainage was required apart from a 4 in. (100 mm) layer of free-draining aggregate that supported the soil cells. Once the soil cells were installed, they were backfilled with topsoil in layers, and a compacting plate was used to consolidate the cell structure, vibrating the soil into the cells to eliminate voids. The soil cells were then overlaid with a geotextile fabric to provide separation from the subsequent layers of road stone required to build up to the finished surface paving level.
Results
In 2013, the tree was assessed visually and new shoot extension, color, and girth were measured, and the height was calculated. Samples of leaves were removed for leaf chlorophyll measurements to determine the tree’s health and vitality.
Initial visual results were apparent and very positive, as substantiated in the photo below. The tree appears healthy and vigorous with excellent new shoot extension. Close assessment of the surface surrounding the planting location confirmed that there was no pavement deflection evident at the site attributable to surface root heave. In this review, 12 years after planting, the tree had attained a height of 33 ft (10.8 m) (even after severe crown reduction for maintenance) and a dbh of 10 in (23 cm). The leaf chlorophyll fluorescence indicated that the tree is in good health, photosynthesizing well, and not under any significant latent stress.
In May 2014, the latest in root radar technology devices was used to map out where the roots actually were after 13 years in the soil cell system. This root radar detects the depth and spread of all roots over ¾ in. (20mm) in diameter. The radar showed the roots to be uniformly spread, after having been trained downwards by the root deflector. They had advanced beyond the initial area of soil cells and extended further without returning towards the surface - see Photo.
The tree appears to be growing very well and by assessment shows excellent vigor and health, despite the challenging urban environment. While the years at this location is not a large portion of a trees potential life span, it is encouraging to see that this tree is already bringing significant environmental benefits to the area.
It is also noteworthy that the shallow root deflection technique designed into this tree pit has been effective, as the tree flourished without any damage to the paved surface, which is so commonly seen in many urban tree plantings.
Sources
Special thanks to Ben Gooden, Founder of CityGreen and Dean Bowie, CEO of GreenBlue Urban
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Tree Planting
Edited by Len Phillips
Blackheath Hill, Greenwich, is an area of southeast London, England, noted for its traditional pubs, quaint village, and an extensively large green space. In 2001, a street, sidewalk, and tree improvement project was undertaken at the main cross-roads in Blackheath Hill. When the tree was planted it was one of the first installations in the world utilizing a soil-support cell system that was designed to encourage tree root growth. See Photo
The concept was to provide a high-quality soil cell tree pit, limited in volume due to the close proximity of buildings, but capable of permitting vehicular traffic on the surface of the tree pit adjacent to one of the busiest routes into the city. The international engineering group involved in the design identified a planting location, but realized that without proper provision below ground, the tree would become an expensive failure.
The consultant designed a tree pit incorporating a tree planting system that provided soil cells to offer non-compacted soil volume for root growth, a tree pit irrigation/aeration system to provide the vital moisture and oxygen that every tree needs, and a system to direct roots away from paved surfaces and utilities and into the intended rooting zone.
The tree pit was designed to be 16 feet (5 meters) long by 3.5 ft (1m) wide by 3.5 ft (1m) deep which provided a 200 cubic ft (5 cubic m) area of excellent soil. The planting location was 12 ft (4m) from the nearest building, and the surface around the tree was continuous pavement with irrigation/aeration inlets set into the granite paving stone on the surface.
Having been directed downwards by a shallow root barrier product, to an appropriate level below the paved surface, the roots grew into the load bearing soil cells. The cells were intended in this instance to provide enough soil for the complete life of the tree. The tree's ultimate size had to be limited because of branch space constraints and also to protect the utilities and services surrounding the tree pit area. This type of tree pit is designed for constricted space applications above ground where it is not possible to provide large volume ‘complete life’ branch growth, and limited below ground soil cell structures due to lack of space not occupied with utilities and surface pavements.
Tree Pit Details & Installation
The outer perimeter of the tree pit was lined on three sides with a high-density polyethylene root barrier. The purpose of this was to contain roots within an intended area, while preventing roots from spreading laterally but allowing them to spread deeper. Within that perimeter, the load bearing soil cells were placed on two sides of the tree and filled with a sandy loam topsoil mix.
Compaction and drainage at the base of the tree pit were critical. In this instance, the tree pit was free-draining so no additional drainage was required apart from a 4 in. (100 mm) layer of free-draining aggregate that supported the soil cells. Once the soil cells were installed, they were backfilled with topsoil in layers, and a compacting plate was used to consolidate the cell structure, vibrating the soil into the cells to eliminate voids. The soil cells were then overlaid with a geotextile fabric to provide separation from the subsequent layers of road stone required to build up to the finished surface paving level.
Results
In 2013, the tree was assessed visually and new shoot extension, color, and girth were measured, and the height was calculated. Samples of leaves were removed for leaf chlorophyll measurements to determine the tree’s health and vitality.
Initial visual results were apparent and very positive, as substantiated in the photo below. The tree appears healthy and vigorous with excellent new shoot extension. Close assessment of the surface surrounding the planting location confirmed that there was no pavement deflection evident at the site attributable to surface root heave. In this review, 12 years after planting, the tree had attained a height of 33 ft (10.8 m) (even after severe crown reduction for maintenance) and a dbh of 10 in (23 cm). The leaf chlorophyll fluorescence indicated that the tree is in good health, photosynthesizing well, and not under any significant latent stress.
In May 2014, the latest in root radar technology devices was used to map out where the roots actually were after 13 years in the soil cell system. This root radar detects the depth and spread of all roots over ¾ in. (20mm) in diameter. The radar showed the roots to be uniformly spread, after having been trained downwards by the root deflector. They had advanced beyond the initial area of soil cells and extended further without returning towards the surface - see Photo.
The tree appears to be growing very well and by assessment shows excellent vigor and health, despite the challenging urban environment. While the years at this location is not a large portion of a trees potential life span, it is encouraging to see that this tree is already bringing significant environmental benefits to the area.
It is also noteworthy that the shallow root deflection technique designed into this tree pit has been effective, as the tree flourished without any damage to the paved surface, which is so commonly seen in many urban tree plantings.
Sources
Special thanks to Ben Gooden, Founder of CityGreen and Dean Bowie, CEO of GreenBlue Urban
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Summer Branch Drop
Edited by Len Phillips
In the middle of summer, on a clear, sunny day, perfectly sound limbs occasionally break out of mature trees for no apparent reason. This type of limb failure occurs on trees planted from nurseries as well as trees grown in a forest, on irrigated and non-irrigated landscapes. This limb failure is called summer branch drop (also known as “sudden limb failure”). Summer branch drop is a process in which trees shed their branches or “self-prune” in response to stress through the formation of an abscission layer at the branch base. Sources of stress which may contribute to this shedding include drought, soil and root compaction, or presence of disease. It is similar to cladoptosis which is a process in which trees shed their branches or “self-prune” as part of their normal physiology instead of dropping leaves in autumn. Cladoptosis occurs annually with certain cedars and some other trees. Summer branch drop occurs unexpectedly.
People have been seriously injured and property has been damaged by these falling branches. The limb drop happens mostly without warning. But if you hear a loud popping sound while under a tree, get out of the way immediately.
There are three primary characteristics that must be present to attribute the event to Summer Branch Drop.
· First, it has to occur on a large mature tree.
· Second, the event must take place during a prolonged dry summer period.
· Third, there must be no obvious defect or other cause.
Branch Attachment
Most commonly, breakage occurs on long, horizontal limbs that extend to or beyond the tree canopy. The break usually occurs 3 to 12 feet (1 – 4 m) away from the trunk, along the length of the branch. Sometimes a branch may fail at its attachment. Less frequently, the main leader or the entire tree top may fail.
No outward appearance has been associated with impending branch failure. The wood at many breaks appears sound, while some other failures appear on decayed wood. Much of the wood may be broken short and at right angles to the axis of the branch. Decayed wood may indicate the possibility of failure, but it does not account for failure occurring under all conditions. Once a tree has lost a limb due to summer branch drop, it is likely to lose another.
Possible Explanations
At first, summer branch failure was thought to be caused by times of high temperature in arid regions, that occur in Australia, South Africa, and southwestern United States, because, until recently no one identified this problem in other parts of the United States.
Summer branch drop is not related to wind and often occurs in the afternoon of hot, calm days. Researchers at this point in time, have not been able to determine the exact cause of Summer Branch Drop, but here are some of the most reasonable explanations.
Drought – Most tree experts believe a lack of adequate soil moisture, or drought stress, is to blame. This is a bit difficult to explain, since branches actually become lighter during hot weather as they lose more water from transpiring leaves than they gain from the root system. Studies have shown that branches actually shrink and rise during summer afternoons.
Ethylene Production – The reduced flow of water in the branch also causes the branch temperature to increase and in turn causes the concentration of ethylene to increase. Ethylene is known to promote the process of cell aging. Elevated levels of ethylene may weaken the cell wall cementation, which then reduces transpiration and increases internal sap pressure, which then increases the moisture content of the branches, and increases limb weight, resulting in branch failure.
Too Much Water – On the other hand, after a break, water has been observed "flowing" from both sides of the fracture. Sometimes there are spots of discoloration on a limb, where water was "bleeding." This makes sense because of the added weight from the water accumulating in the limb. These observations indicated the xylem to be under pressure, at least in these instances. High humidity was also reported in many of these situations.
Wounds, Wood Decay, and Cracks – While some broken branches may have wounds or areas of wood decay, most branches that drop are free of any obvious defects and appear sound. There is the possibility that internal cracks in large branches, caused by wounds or improper pruning many years previous, eventually spread outward, causing the branch to fracture. However, this does not account for the majority of summer branch drop failures.
Poor Maintenance – Poor pruning may result in excess foliage at the end of a limb, making it too heavy to support. But this is not always the case.
Wind Gust – One less likely possibility suggests that a combination of heavy foliage and a hot day where the tree sucks up water adding weight, results in failure from a gust of wind.
Suggested precautions
While the cause is unknown, there are several precautions that should be taken to prevent injury to people under suspect trees before branch failure occurs.
· Warn people of potential hazard or rope off areas near hazardous trees. This would be most important from
late spring to early fall.
· In areas to be frequented by people, do not plant species known to be susceptible to this problem.
· On mature trees, shorten and lighten long horizontal branches and open up the tree by thinning to healthy
lateral branches. This will reduce branch weight and reduce humidity build up.
· Keep trees vigorous and healthy. However, this may be self defeating since potentially susceptible branches
would become longer and heavier, but hopefully stronger.
· Inspect susceptible trees for externally visible defects, removing damaged or sickly low-vigor limbs that have
decay or cavities. An entire tree should be removed if decayed and of low vigor.
· Although watering is required to keep most ornamental trees healthy in a hot summer climate, do not forget
that summer moisture can encourage oak root fungus and other oak pathogens that can kill oaks when the
summer-watered area is within 10 feet of the trunk.
· Do not park cars or place play structures, benches, or picnic tables beneath older, susceptible trees.
Trees Affected
Although this phenomenon is not limited to oaks, the sheer size of their branches makes summer branch drop in oaks much more hazardous for life and property than branch drop by other tree species. Limb failure has been reported on 19 genera. Young and vigorous maturing trees of susceptible species seem to be less prone to branch failure while mature or veteran trees may shed branches repeatedly.
Trees reported to be most susceptible to summer branch drop:
Quercus spp.
Acer spp. (this may be cladoptosis)
Populus spp.
Salix spp. (this may be cladoptosis)
Ulmus procera
Castanea sativa
Fagus sylvatica
Fraxinus excelsior
Aesculus hippocastanum
Genera most often reported in California:
Eucalyptus
Quercus
Ulmus
Pinus (this may be cladoptosis)
Cedrus (this may be cladoptosis)
Fraxinus (this may be cladoptosis)
Platanus
Species also reported in California:
Ailanthus altissima
Erythrina caffra
Ficus microcarpa
Olea europaea
Grevillea robusta
Sequoiadendron giganteum
Sophora japonica
Sources
· Carter, J.C. “The Wetwood Disease of Elm”, Illinois Natural History Survey Circ. 50, 1969.
· Harris, R.W. “Summer Branch Drop” Journal of Arboriculture, April 1983.
· McGhie, Brent, “Summer Branch Drop”, The Real Dirt Blog, August 14, 2015
· Rushforth, K.D. “Summer branch drop”, British Dept. of the Environment, 1979.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
In the middle of summer, on a clear, sunny day, perfectly sound limbs occasionally break out of mature trees for no apparent reason. This type of limb failure occurs on trees planted from nurseries as well as trees grown in a forest, on irrigated and non-irrigated landscapes. This limb failure is called summer branch drop (also known as “sudden limb failure”). Summer branch drop is a process in which trees shed their branches or “self-prune” in response to stress through the formation of an abscission layer at the branch base. Sources of stress which may contribute to this shedding include drought, soil and root compaction, or presence of disease. It is similar to cladoptosis which is a process in which trees shed their branches or “self-prune” as part of their normal physiology instead of dropping leaves in autumn. Cladoptosis occurs annually with certain cedars and some other trees. Summer branch drop occurs unexpectedly.
People have been seriously injured and property has been damaged by these falling branches. The limb drop happens mostly without warning. But if you hear a loud popping sound while under a tree, get out of the way immediately.
There are three primary characteristics that must be present to attribute the event to Summer Branch Drop.
· First, it has to occur on a large mature tree.
· Second, the event must take place during a prolonged dry summer period.
· Third, there must be no obvious defect or other cause.
Branch Attachment
Most commonly, breakage occurs on long, horizontal limbs that extend to or beyond the tree canopy. The break usually occurs 3 to 12 feet (1 – 4 m) away from the trunk, along the length of the branch. Sometimes a branch may fail at its attachment. Less frequently, the main leader or the entire tree top may fail.
No outward appearance has been associated with impending branch failure. The wood at many breaks appears sound, while some other failures appear on decayed wood. Much of the wood may be broken short and at right angles to the axis of the branch. Decayed wood may indicate the possibility of failure, but it does not account for failure occurring under all conditions. Once a tree has lost a limb due to summer branch drop, it is likely to lose another.
Possible Explanations
At first, summer branch failure was thought to be caused by times of high temperature in arid regions, that occur in Australia, South Africa, and southwestern United States, because, until recently no one identified this problem in other parts of the United States.
Summer branch drop is not related to wind and often occurs in the afternoon of hot, calm days. Researchers at this point in time, have not been able to determine the exact cause of Summer Branch Drop, but here are some of the most reasonable explanations.
Drought – Most tree experts believe a lack of adequate soil moisture, or drought stress, is to blame. This is a bit difficult to explain, since branches actually become lighter during hot weather as they lose more water from transpiring leaves than they gain from the root system. Studies have shown that branches actually shrink and rise during summer afternoons.
Ethylene Production – The reduced flow of water in the branch also causes the branch temperature to increase and in turn causes the concentration of ethylene to increase. Ethylene is known to promote the process of cell aging. Elevated levels of ethylene may weaken the cell wall cementation, which then reduces transpiration and increases internal sap pressure, which then increases the moisture content of the branches, and increases limb weight, resulting in branch failure.
Too Much Water – On the other hand, after a break, water has been observed "flowing" from both sides of the fracture. Sometimes there are spots of discoloration on a limb, where water was "bleeding." This makes sense because of the added weight from the water accumulating in the limb. These observations indicated the xylem to be under pressure, at least in these instances. High humidity was also reported in many of these situations.
Wounds, Wood Decay, and Cracks – While some broken branches may have wounds or areas of wood decay, most branches that drop are free of any obvious defects and appear sound. There is the possibility that internal cracks in large branches, caused by wounds or improper pruning many years previous, eventually spread outward, causing the branch to fracture. However, this does not account for the majority of summer branch drop failures.
Poor Maintenance – Poor pruning may result in excess foliage at the end of a limb, making it too heavy to support. But this is not always the case.
Wind Gust – One less likely possibility suggests that a combination of heavy foliage and a hot day where the tree sucks up water adding weight, results in failure from a gust of wind.
Suggested precautions
While the cause is unknown, there are several precautions that should be taken to prevent injury to people under suspect trees before branch failure occurs.
· Warn people of potential hazard or rope off areas near hazardous trees. This would be most important from
late spring to early fall.
· In areas to be frequented by people, do not plant species known to be susceptible to this problem.
· On mature trees, shorten and lighten long horizontal branches and open up the tree by thinning to healthy
lateral branches. This will reduce branch weight and reduce humidity build up.
· Keep trees vigorous and healthy. However, this may be self defeating since potentially susceptible branches
would become longer and heavier, but hopefully stronger.
· Inspect susceptible trees for externally visible defects, removing damaged or sickly low-vigor limbs that have
decay or cavities. An entire tree should be removed if decayed and of low vigor.
· Although watering is required to keep most ornamental trees healthy in a hot summer climate, do not forget
that summer moisture can encourage oak root fungus and other oak pathogens that can kill oaks when the
summer-watered area is within 10 feet of the trunk.
· Do not park cars or place play structures, benches, or picnic tables beneath older, susceptible trees.
Trees Affected
Although this phenomenon is not limited to oaks, the sheer size of their branches makes summer branch drop in oaks much more hazardous for life and property than branch drop by other tree species. Limb failure has been reported on 19 genera. Young and vigorous maturing trees of susceptible species seem to be less prone to branch failure while mature or veteran trees may shed branches repeatedly.
Trees reported to be most susceptible to summer branch drop:
Quercus spp.
Acer spp. (this may be cladoptosis)
Populus spp.
Salix spp. (this may be cladoptosis)
Ulmus procera
Castanea sativa
Fagus sylvatica
Fraxinus excelsior
Aesculus hippocastanum
Genera most often reported in California:
Eucalyptus
Quercus
Ulmus
Pinus (this may be cladoptosis)
Cedrus (this may be cladoptosis)
Fraxinus (this may be cladoptosis)
Platanus
Species also reported in California:
Ailanthus altissima
Erythrina caffra
Ficus microcarpa
Olea europaea
Grevillea robusta
Sequoiadendron giganteum
Sophora japonica
Sources
· Carter, J.C. “The Wetwood Disease of Elm”, Illinois Natural History Survey Circ. 50, 1969.
· Harris, R.W. “Summer Branch Drop” Journal of Arboriculture, April 1983.
· McGhie, Brent, “Summer Branch Drop”, The Real Dirt Blog, August 14, 2015
· Rushforth, K.D. “Summer branch drop”, British Dept. of the Environment, 1979.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Cultivars of Callery Pear
Edited By Len Phillips
The following cultivars of Callery Pear, (Pyrus) offer unique forms, fast growth, and are well adapted to hot, dry urban climates. The Callery Pear in some areas is considered an escaped exotic tree that can now be found along roadways, city parks, and other undesirable locations. In many other locations however, it is still considered a desirable tree and is not considered invasive. The description that follows provides a summary of similarities that all the available cultivars possess.
Family: Rosaceae
Bloom Period: Early to mid-March
Flower: White and abundant, except as noted
Fruit: Small, greenish brown
Spring color: Leaves emerge with a purple tint
Winter Color: Interesting bark, open form
Bark: New growth displayed on sturdy bluish gray stems and brown trunk
Habitat: Native to Korea and China
Culture: Very adaptable to most soils, tolerates drought and pollution, seed from uneaten fruit may germinate and become invasive in some locations
Hardiness Zone: 4 – 9
Growth Rate: Moderate to fast, full size in 30 years, 2' a year in youth, 1’ a year later
Pest Problems: Resistant to fireblight
Storm Resistance: Excellent for cultivars mentioned
Salt Resistance: Excellent
Planting: Easily transplanted BR, B&B, or in containers in early spring, suitable for planting in CU-Structural Soil
Pruning: Prune in winter or early spring if needed
Propagating: Cuttings and budding onto P. ussuriensis understock
Design Uses: Excellent specimen for lawns, parks, and streets
Companions: Use with Vinca, Juniperus, and other low ground covers
Available cultivars include:
Aristocrat® Pear – Pyrus calleryana ‘Aristocrat’
Height – 40’; Spread – 28’; Foliage – narrow, dark green, glossy; Fall Color – deep red
An outstanding selection with a pyramidal growth habit, Aristocrat® has an open, informal appearance. Its branch angles are wider than other pears, which makes it more resistant to storm damage. Aristocrat® is highly rated by the Ohio Shade Tree Evaluation Project. Fact Sheet
Autumn Blaze Pear – Pyrus calleryana ‘Autumn Blaze’
Height – 30'; Spread – 25'; Foliage – glossy green; Fall Color – bright red
Rounded shape with spreading branches, the Autumn Blaze foliage emerges with a red tint and matures to glossy green. This tree has the best cold hardiness of the Callery pears, and it is also the earliest to develop fall color. Fact Sheet
Capital Pear – Pyrus calleryana ‘Capital’
Height – 35’; Spread – 12’; Foliage – medium green, glossy; Fall Color – reddish-purple.
Capital Pear has a columnar form and was introduced by U.S. National Arboretum. It has large clusters of flowers. Fact Sheet
Chanticleer® Pear – Pyrus calleryana ‘Glen’s Form’
Height – 40'; Spread – 15'; Shape – upright, narrowly pyramidal; Foliage – green, glossy; Fall Color – reddish
Chanticleer® is a densely growing tree that was selected for its suitability for street tree plantings by Ed Scanlon, Cleveland, OH city forester. It is resistant to fireblight and much less susceptible to breakage than Bradford. Fact Sheet
Javelin® Pear – Pyrus ‘NCPX1’
Height – 35’; Spread – 10’; Foliage – purple to bronze green; Fall Color – purple to maroon; Flower – pink buds open to white flowers. Javelin® is the tightest and most columnar of all the Callery Pears. It stays narrow as it matures. The unique foliage emerges purple and matures to a bronze green in the heat of summer. It was developed at North Carolina State University. This fireblight resistant pear is a great addition as a landscape exclamation point or for use on narrow streets. Fact Sheet
New Bradford® Pear – Pyrus calleryana ‘Holmford’
Height – 35'; Spread – 30'; Shape – broadly oval to rounded; Foliage – green, glossy.
The summer foliage and bright yellow to orange fall color provide all-season beauty to the landscape. This cultivar is similar in appearance to the well known ‘Bradford’, but it's branching structure makes it less susceptible to storm damage. Fact Sheet
Redspire Pear – Pyrus calleryana ‘Redspire’
Height – 35'; Spread – 25'; Foliage – medium green, glossy; Fall Color – yellow to red
A pyramidal shape and tight branching habit give this tree a formal appearance. Redspire has better branch structure than Bradford, and it stays smaller and narrower. Fact Sheet
Silver Ball™ Pear – Pyrus ‘Silver Ball’
Height – 12'; Spread – 12'; Foliage – silver gray; Fall Color – yellow-orange
This round, compact dwarf pear features tiny silvery green leaves that give it a fine textured appearance. Silver Ball™ is an introduction by Harold Pellett and the Landscape Plant Development Center in MN. It is the most dwarf pear currently available.
Trinity Pear – Pyrus calleryana ‘Trinity’
Height - 30'; Spread – 25'; Foliage – glossy green; Fall Color – orange-red
Trinity is a slightly smaller growing pear with a tight, rounded form.
Sources:
This information has been gathered from personal observations of the author, living in Massachusetts, Zone 6
and information provided by the following: J. Frank Schmidt & Son and CU-Structural Soil.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited By Len Phillips
The following cultivars of Callery Pear, (Pyrus) offer unique forms, fast growth, and are well adapted to hot, dry urban climates. The Callery Pear in some areas is considered an escaped exotic tree that can now be found along roadways, city parks, and other undesirable locations. In many other locations however, it is still considered a desirable tree and is not considered invasive. The description that follows provides a summary of similarities that all the available cultivars possess.
Family: Rosaceae
Bloom Period: Early to mid-March
Flower: White and abundant, except as noted
Fruit: Small, greenish brown
Spring color: Leaves emerge with a purple tint
Winter Color: Interesting bark, open form
Bark: New growth displayed on sturdy bluish gray stems and brown trunk
Habitat: Native to Korea and China
Culture: Very adaptable to most soils, tolerates drought and pollution, seed from uneaten fruit may germinate and become invasive in some locations
Hardiness Zone: 4 – 9
Growth Rate: Moderate to fast, full size in 30 years, 2' a year in youth, 1’ a year later
Pest Problems: Resistant to fireblight
Storm Resistance: Excellent for cultivars mentioned
Salt Resistance: Excellent
Planting: Easily transplanted BR, B&B, or in containers in early spring, suitable for planting in CU-Structural Soil
Pruning: Prune in winter or early spring if needed
Propagating: Cuttings and budding onto P. ussuriensis understock
Design Uses: Excellent specimen for lawns, parks, and streets
Companions: Use with Vinca, Juniperus, and other low ground covers
Available cultivars include:
Aristocrat® Pear – Pyrus calleryana ‘Aristocrat’
Height – 40’; Spread – 28’; Foliage – narrow, dark green, glossy; Fall Color – deep red
An outstanding selection with a pyramidal growth habit, Aristocrat® has an open, informal appearance. Its branch angles are wider than other pears, which makes it more resistant to storm damage. Aristocrat® is highly rated by the Ohio Shade Tree Evaluation Project. Fact Sheet
Autumn Blaze Pear – Pyrus calleryana ‘Autumn Blaze’
Height – 30'; Spread – 25'; Foliage – glossy green; Fall Color – bright red
Rounded shape with spreading branches, the Autumn Blaze foliage emerges with a red tint and matures to glossy green. This tree has the best cold hardiness of the Callery pears, and it is also the earliest to develop fall color. Fact Sheet
Capital Pear – Pyrus calleryana ‘Capital’
Height – 35’; Spread – 12’; Foliage – medium green, glossy; Fall Color – reddish-purple.
Capital Pear has a columnar form and was introduced by U.S. National Arboretum. It has large clusters of flowers. Fact Sheet
Chanticleer® Pear – Pyrus calleryana ‘Glen’s Form’
Height – 40'; Spread – 15'; Shape – upright, narrowly pyramidal; Foliage – green, glossy; Fall Color – reddish
Chanticleer® is a densely growing tree that was selected for its suitability for street tree plantings by Ed Scanlon, Cleveland, OH city forester. It is resistant to fireblight and much less susceptible to breakage than Bradford. Fact Sheet
Javelin® Pear – Pyrus ‘NCPX1’
Height – 35’; Spread – 10’; Foliage – purple to bronze green; Fall Color – purple to maroon; Flower – pink buds open to white flowers. Javelin® is the tightest and most columnar of all the Callery Pears. It stays narrow as it matures. The unique foliage emerges purple and matures to a bronze green in the heat of summer. It was developed at North Carolina State University. This fireblight resistant pear is a great addition as a landscape exclamation point or for use on narrow streets. Fact Sheet
New Bradford® Pear – Pyrus calleryana ‘Holmford’
Height – 35'; Spread – 30'; Shape – broadly oval to rounded; Foliage – green, glossy.
The summer foliage and bright yellow to orange fall color provide all-season beauty to the landscape. This cultivar is similar in appearance to the well known ‘Bradford’, but it's branching structure makes it less susceptible to storm damage. Fact Sheet
Redspire Pear – Pyrus calleryana ‘Redspire’
Height – 35'; Spread – 25'; Foliage – medium green, glossy; Fall Color – yellow to red
A pyramidal shape and tight branching habit give this tree a formal appearance. Redspire has better branch structure than Bradford, and it stays smaller and narrower. Fact Sheet
Silver Ball™ Pear – Pyrus ‘Silver Ball’
Height – 12'; Spread – 12'; Foliage – silver gray; Fall Color – yellow-orange
This round, compact dwarf pear features tiny silvery green leaves that give it a fine textured appearance. Silver Ball™ is an introduction by Harold Pellett and the Landscape Plant Development Center in MN. It is the most dwarf pear currently available.
Trinity Pear – Pyrus calleryana ‘Trinity’
Height - 30'; Spread – 25'; Foliage – glossy green; Fall Color – orange-red
Trinity is a slightly smaller growing pear with a tight, rounded form.
Sources:
This information has been gathered from personal observations of the author, living in Massachusetts, Zone 6
and information provided by the following: J. Frank Schmidt & Son and CU-Structural Soil.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Japanese Beetle
Edited by Len Phillips
The Japanese beetle, Popillia japonica, was first found in the US in 1916 in southern New Jersey. Japanese beetles are related to Asiatic garden beetles, and oriental beetles. The damage they cause depends on the numbers of beetles and the amount of defoliation taking place. However, it can be difficult to know what the damaging pest might be until they have eaten a sufficient number of roots to cause trees to wilt and die. An arborist must be familiar with these pests, often seen on lindens and roses.
In North America the Japanese beetle found a suitable climate, large areas of turf for development of the larvae, and more than 350 plant species as hosts for the adult beetle. These favorable conditions and an absence of Japanese beetle natural enemies allowed the Japanese beetle to become established in twenty-six states, ranging north to Ontario, west to Illinois and south to Georgia. At this time there is also a population in California.
Description
The adult beetle is a little less than ½ inch (1 cm) long and rather oval-shaped. The body is a brilliant metallic green. The coppery brown wing-covers leave exposed a row of five lateral spots of white hairs on each side of the abdomen - see Photo.
Damage
The adult Japanese beetle is a serious pest of shade trees, ornamental shrubs and vines, and many garden plants. The beetles feed on the upper surface of tree leaves, chewing out the tissue between the veins and leaving a lace-like skeleton - see Photo. The injured leaves eventually turn brown and premature defoliation may occur. The trees most severely attacked include lindens, elms, Japanese maple, Norway maple, horse chestnut, birches, black walnut, apples, cherries, plum, and mountain ash. The beetles are very damaging to roses, corn silk, grapevines, asparagus, rhubarb, and many fruits. The beetles prefer to feed on plants in the full sun, rarely attacking plants in dense shade. The larva feed on roots and destroys large areas of turf in lawns and pastures.
Life Cycle
Adult beetles begin to emerge from the soil in early summer, generally in late May in the southern part of their range, and late June in the northern regions. They soon reach a peak of abundance and are still numerous in September. After feeding and mating, the females burrow two to four inches (1-2 cm) into soil to deposit eggs in the vicinity of a host plant.
Control
The usual strategy is to manage the larval populations with applications of insecticides to soil or turf, resulting in much less injury from the adults. Killing off the larva treatments can also significantly reduce the damage to lawns from moles, crows, starlings, skunks, and fox, etc. Moles are principally insectivorous; however, tunneling in a lawn from moles may be unaffected by eliminating Japanese beetle larva because earthworms are also an important food for moles.
Soil Treatments: There is currently no non-chemical method, which will totally protect individual shade trees and gardens from beetle feeding. Soil treatments are made in late summer or early fall for beetle control the next year. Most homeowners and lawn care operators prefer granular products over liquid sprays, and the granular products are less hazardous to bees.
Milky Spore (Paenibacillus popilliae, formerly Bacillus popilliae) is a bacteria that is very safe and a simple product to use. One teaspoon of granular product dropped in the center of every square yard (1 sq. meter) of lawn area, is effective and it is a multi-year treatment. Researchers have mixed reports on this product. At some Midwest locations, this treatment is considered a waste of money while other researchers indicate it works quite well. It is best to contact your local university or extension office before using this product.
Plant Treatments: Control of Japanese beetle adults on trees can also be achieved through soil applied or trunk injectable insecticides. Trunk injected insecticides are made when at the first sign of the beetles. A foliar applied insecticide should only be made as a last resort under extreme beetle infestations. For the past 20 years, control consisted of imidacloprid (Merit, and many other names) for chemical control of larvae. This insecticide, and similar, newer neonicotinoids like clothianidin (Arena) and thiamethoxam (Flagship) were a tremendous advance in larvae control because they were much more effective, safer to humans and pets, and applied at considerably lower dosages than the insecticides that they replaced.
However, there are several important reasons to consider changing insecticides for managing the larvae:
multiple years of using the same insecticide for controlling the same pest results in insecticide resistance development. There is concern that the indiscriminate use of neonicotinoids may be injurious to beneficial pollinator insects. For example, neonicotinoids sprayed on a lawn containing blooming clover is harmful to bees. Researchers found that bees foraging from blossoms directly sprayed with neonicotinoids died, and that the colonies were unable to produce new queens, even though spraying open blossoms is prohibited by the label directions. When the clover blossoms were mowed, the bees foraged on blossoms that opened after spraying. Bumble bee survival and reproduction is unaffected.
Other products are available with varying toxicities so care must be taken before use.
Sources
· Bartlett Tree Research Laboratories Technical Report, “Japanese Beetle, Identification, Biology and
Management”.
· Cowles, Richard S. Ph.D., “White Grubs”, Connecticut Gardener, CAES Valley Lab, July/August 2015.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
The Japanese beetle, Popillia japonica, was first found in the US in 1916 in southern New Jersey. Japanese beetles are related to Asiatic garden beetles, and oriental beetles. The damage they cause depends on the numbers of beetles and the amount of defoliation taking place. However, it can be difficult to know what the damaging pest might be until they have eaten a sufficient number of roots to cause trees to wilt and die. An arborist must be familiar with these pests, often seen on lindens and roses.
In North America the Japanese beetle found a suitable climate, large areas of turf for development of the larvae, and more than 350 plant species as hosts for the adult beetle. These favorable conditions and an absence of Japanese beetle natural enemies allowed the Japanese beetle to become established in twenty-six states, ranging north to Ontario, west to Illinois and south to Georgia. At this time there is also a population in California.
Description
The adult beetle is a little less than ½ inch (1 cm) long and rather oval-shaped. The body is a brilliant metallic green. The coppery brown wing-covers leave exposed a row of five lateral spots of white hairs on each side of the abdomen - see Photo.
Damage
The adult Japanese beetle is a serious pest of shade trees, ornamental shrubs and vines, and many garden plants. The beetles feed on the upper surface of tree leaves, chewing out the tissue between the veins and leaving a lace-like skeleton - see Photo. The injured leaves eventually turn brown and premature defoliation may occur. The trees most severely attacked include lindens, elms, Japanese maple, Norway maple, horse chestnut, birches, black walnut, apples, cherries, plum, and mountain ash. The beetles are very damaging to roses, corn silk, grapevines, asparagus, rhubarb, and many fruits. The beetles prefer to feed on plants in the full sun, rarely attacking plants in dense shade. The larva feed on roots and destroys large areas of turf in lawns and pastures.
Life Cycle
Adult beetles begin to emerge from the soil in early summer, generally in late May in the southern part of their range, and late June in the northern regions. They soon reach a peak of abundance and are still numerous in September. After feeding and mating, the females burrow two to four inches (1-2 cm) into soil to deposit eggs in the vicinity of a host plant.
Control
The usual strategy is to manage the larval populations with applications of insecticides to soil or turf, resulting in much less injury from the adults. Killing off the larva treatments can also significantly reduce the damage to lawns from moles, crows, starlings, skunks, and fox, etc. Moles are principally insectivorous; however, tunneling in a lawn from moles may be unaffected by eliminating Japanese beetle larva because earthworms are also an important food for moles.
Soil Treatments: There is currently no non-chemical method, which will totally protect individual shade trees and gardens from beetle feeding. Soil treatments are made in late summer or early fall for beetle control the next year. Most homeowners and lawn care operators prefer granular products over liquid sprays, and the granular products are less hazardous to bees.
Milky Spore (Paenibacillus popilliae, formerly Bacillus popilliae) is a bacteria that is very safe and a simple product to use. One teaspoon of granular product dropped in the center of every square yard (1 sq. meter) of lawn area, is effective and it is a multi-year treatment. Researchers have mixed reports on this product. At some Midwest locations, this treatment is considered a waste of money while other researchers indicate it works quite well. It is best to contact your local university or extension office before using this product.
Plant Treatments: Control of Japanese beetle adults on trees can also be achieved through soil applied or trunk injectable insecticides. Trunk injected insecticides are made when at the first sign of the beetles. A foliar applied insecticide should only be made as a last resort under extreme beetle infestations. For the past 20 years, control consisted of imidacloprid (Merit, and many other names) for chemical control of larvae. This insecticide, and similar, newer neonicotinoids like clothianidin (Arena) and thiamethoxam (Flagship) were a tremendous advance in larvae control because they were much more effective, safer to humans and pets, and applied at considerably lower dosages than the insecticides that they replaced.
However, there are several important reasons to consider changing insecticides for managing the larvae:
multiple years of using the same insecticide for controlling the same pest results in insecticide resistance development. There is concern that the indiscriminate use of neonicotinoids may be injurious to beneficial pollinator insects. For example, neonicotinoids sprayed on a lawn containing blooming clover is harmful to bees. Researchers found that bees foraging from blossoms directly sprayed with neonicotinoids died, and that the colonies were unable to produce new queens, even though spraying open blossoms is prohibited by the label directions. When the clover blossoms were mowed, the bees foraged on blossoms that opened after spraying. Bumble bee survival and reproduction is unaffected.
Other products are available with varying toxicities so care must be taken before use.
Sources
· Bartlett Tree Research Laboratories Technical Report, “Japanese Beetle, Identification, Biology and
Management”.
· Cowles, Richard S. Ph.D., “White Grubs”, Connecticut Gardener, CAES Valley Lab, July/August 2015.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Sustainable Trees
Edited by Len Phillips
What is a sustainable tree?
Careful tree selection is the first step in developing a balanced and self-perpetuating landscape. However, tree survival with minimal maintenance is not the only issue in sustainability. Landscape trees that are more sustainable are those which are not invasive and require reduced levels of pesticides, water, and maintenance. Arborists should become aware of the limits of our natural resources and the precarious balance of nature in which we play a pivotal role.
Sustainable shade trees are those that have been selected to survive and thrive in harsh urban conditions because they are drought tolerant, or disease resistant, or insect resistant, or make efficient use of nutrients and water. They are proven to be predictable and dependable large shade trees that outlive, outlast, and outperform other varieties of trees, expanding their benefits for future generations.
Another way to look at sustainability from the viewpoint of the arborist, naturalist, and gardener, means that we do not use a resource to the point that it has a negative consequence on future generations’ abilities to use the same resource. When applied to trees, sustainability means tree removals are a last resort unless they pose a hazard. Sustainability also means that proper selection, placement, and care are required to ensure trees will live to their full potential, and provide the maximum benefit for future generations.
Sustainable Site Selection
In a sustainable tree-planting project, trees not only survive, but also grow stronger limbs and live to the normal life expectancy for the species. Research a particular species and its growth habit before you determine its location. A large-growing oak does not belong over a swimming pool because it drops acorns, leaves, and flowers into the pool, even though the shade might be desirable. Also, consider the future growth of near-by trees before selecting a location. Trees without adequate sunlight for the species do not develop to their full potential.
When selecting the site, be sure a tree will have adequate root space and healthy soil. Trees surrounded by concrete survive around 20 years, while trees surrounded by soils containing abundant organic matter can live to their full life expectancy, often more than 100 years.
Select a Sustainable Tree
Select quality trees with a proper-sized root ball, a strong branching habit, and healthy foliage or healthy buds in the dormant season.
· A tree, growing in a nursery container that is too small, is not sustainable.
· A 6’ or 8’ (2-2.5 m) tall tree growing in a 5-gallon (20 l.) container, likely has circling roots inside the container and may also require staking to become established. If circling roots are not properly pruned or straightened during the planting process, they continue to grow in a circular pattern, leaving the tree without adequate support and a shorter life span.
· As a rule, a root ball or container should be at least 10”-12” (26-30 cm) wide for each inch in trunk caliper. Bare root trees are very sustainable.
· If there is a situation where staking is necessary, stabilizing the root ball is more sustainable than staking because the cost and labor required is much less. In addition, since most stabilizing systems are underground, they do not have to be removed.
Sustainable Tree Maintenance
Sustainability also requires providing sufficient maintenance during the establishment period.
· Staking should not be necessary to prevent the tree from blowing over.
· Proper maintenance is critical for a minimum of 5 years for newly planted trees up to 1.5” (4 cm) caliper, and 3 years for trees between 2″ and 4” (5-10 cm) caliper unless there is a long period of drought anytime during the establishment period.
· All trees need a minimum amount of water throughout their lifetime.
The use of potential invasives cannot be seen as sustainable except in very controlled situations. There is great difficulty with invasive exotic trees that have escaped from managed landscapes, displaced native trees, and have disrupted natural ecosystems. Research is required to determine invasiveness. The callery pear is a prime example of an escaped exotic tree that can now be found along roadways, city parks, and other undesirable locations throughout the southeastern United States. However, this same callery pear is not considered an invasive problem in the northeastern US.
Site Selection
Lists of sustainable trees are invaluable resources for arborists, garden enthusiasts, designers, nursery trades people, and landscape architects. However, a list of sustainable trees is not the entire answer. Proper siting, planting, and maintenance are necessary for a tree to prosper in the landscape. Therefore, climatic conditions, exposure to sun and wind, subsurface soil and moisture conditions, etc. must be considered when selecting trees for a particular location. Sustainable or not, if one ignores the site and a tree's cultural requirements, that tree will suffer.
Lists of sustainable trees can be obtained from colleges or extension services in your region.
Source
University of Rhode Island, “URI Sustainable Trees and Shrubs Manual”, Bristol, RI. 2003.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
What is a sustainable tree?
Careful tree selection is the first step in developing a balanced and self-perpetuating landscape. However, tree survival with minimal maintenance is not the only issue in sustainability. Landscape trees that are more sustainable are those which are not invasive and require reduced levels of pesticides, water, and maintenance. Arborists should become aware of the limits of our natural resources and the precarious balance of nature in which we play a pivotal role.
Sustainable shade trees are those that have been selected to survive and thrive in harsh urban conditions because they are drought tolerant, or disease resistant, or insect resistant, or make efficient use of nutrients and water. They are proven to be predictable and dependable large shade trees that outlive, outlast, and outperform other varieties of trees, expanding their benefits for future generations.
Another way to look at sustainability from the viewpoint of the arborist, naturalist, and gardener, means that we do not use a resource to the point that it has a negative consequence on future generations’ abilities to use the same resource. When applied to trees, sustainability means tree removals are a last resort unless they pose a hazard. Sustainability also means that proper selection, placement, and care are required to ensure trees will live to their full potential, and provide the maximum benefit for future generations.
Sustainable Site Selection
In a sustainable tree-planting project, trees not only survive, but also grow stronger limbs and live to the normal life expectancy for the species. Research a particular species and its growth habit before you determine its location. A large-growing oak does not belong over a swimming pool because it drops acorns, leaves, and flowers into the pool, even though the shade might be desirable. Also, consider the future growth of near-by trees before selecting a location. Trees without adequate sunlight for the species do not develop to their full potential.
When selecting the site, be sure a tree will have adequate root space and healthy soil. Trees surrounded by concrete survive around 20 years, while trees surrounded by soils containing abundant organic matter can live to their full life expectancy, often more than 100 years.
Select a Sustainable Tree
Select quality trees with a proper-sized root ball, a strong branching habit, and healthy foliage or healthy buds in the dormant season.
· A tree, growing in a nursery container that is too small, is not sustainable.
· A 6’ or 8’ (2-2.5 m) tall tree growing in a 5-gallon (20 l.) container, likely has circling roots inside the container and may also require staking to become established. If circling roots are not properly pruned or straightened during the planting process, they continue to grow in a circular pattern, leaving the tree without adequate support and a shorter life span.
· As a rule, a root ball or container should be at least 10”-12” (26-30 cm) wide for each inch in trunk caliper. Bare root trees are very sustainable.
· If there is a situation where staking is necessary, stabilizing the root ball is more sustainable than staking because the cost and labor required is much less. In addition, since most stabilizing systems are underground, they do not have to be removed.
Sustainable Tree Maintenance
Sustainability also requires providing sufficient maintenance during the establishment period.
· Staking should not be necessary to prevent the tree from blowing over.
· Proper maintenance is critical for a minimum of 5 years for newly planted trees up to 1.5” (4 cm) caliper, and 3 years for trees between 2″ and 4” (5-10 cm) caliper unless there is a long period of drought anytime during the establishment period.
· All trees need a minimum amount of water throughout their lifetime.
The use of potential invasives cannot be seen as sustainable except in very controlled situations. There is great difficulty with invasive exotic trees that have escaped from managed landscapes, displaced native trees, and have disrupted natural ecosystems. Research is required to determine invasiveness. The callery pear is a prime example of an escaped exotic tree that can now be found along roadways, city parks, and other undesirable locations throughout the southeastern United States. However, this same callery pear is not considered an invasive problem in the northeastern US.
Site Selection
Lists of sustainable trees are invaluable resources for arborists, garden enthusiasts, designers, nursery trades people, and landscape architects. However, a list of sustainable trees is not the entire answer. Proper siting, planting, and maintenance are necessary for a tree to prosper in the landscape. Therefore, climatic conditions, exposure to sun and wind, subsurface soil and moisture conditions, etc. must be considered when selecting trees for a particular location. Sustainable or not, if one ignores the site and a tree's cultural requirements, that tree will suffer.
Lists of sustainable trees can be obtained from colleges or extension services in your region.
Source
University of Rhode Island, “URI Sustainable Trees and Shrubs Manual”, Bristol, RI. 2003.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.