Classics
The following article has been selected because it is deemed very important to the arboricultural profession
and deserves special recognition. It has appeared in a previous Seminar and because of this it is not eligible for earning certification credits; there is no test at the end of this article.
Tree Planting Options
Edited by Len Phillips
When you are asked to recommend the best way to preserve or plant new trees in the city, how do you respond? The following can be considered the best options for planting trees in conjunction with a city sidewalk in various site and sidewalk conditions. To start, every tree must have a minimum of 2 cubic feet (0.06 cm) of soil for every square foot (0.1 sm) of the future crown projected at maturity or 4 square feet (0.38 sm) of surface area for every inch (2.5 cm) of trunk diameter the tree is expected to attain, and this should be applied to all the options mentioned below.
⊙ Site – New construction including new sidewalks and new trees
Best Planting Option – During construction of new sidewalks, streets, utilities, and buildings – plant all the trees in groups 10 to 20 ft. (3 – 6m) apart or included shrub beds. Be sure to select trees that are not considered surface rooted trees. For lists of shallow rooted and more desirable trees, see the lists in the opening section of this article. Scroll down the page to see the lists.
Second Best Planting Option – The use of soil cells is the next best method for ensuring there is enough suitable soil for a tree to develop into a mature specimen. Soil cells transfer a compacted foundation 3 ft. (1 m) below grade to a surface suitable for a sidewalk, plaza, or light traffic roadway while allowing plenty of ideal soil for growing trees under the surface. The installation of root barriers to deflect roots downward should be included to prevent the tree's roots from causing damage to the surface pavement. The soil cells will also provide stormwater storage and eliminate the need for watering the trees. See more information.
⊙ Site – New sidewalks and preserve existing trees
Best Option – Carefully examine the condition of the tree and the existing roots to provide care, protection, and root pruning as necessary. Modify the sidewalk design and location to accommodate the tree and its roots. This option is often the result of sidewalk replacements caused by roots that have damaged the existing sidewalks. The best and most common solution is to raise the sidewalk higher which results in the roots being in deeper soil than before the new sidewalk is installed. Include S-curves around the trees and pavement alternatives found in this article.
Second Best Option – Loosen and improve soil including that which will serve as a base for pavement. New sidewalks should be built and suspended on pilings above the tree roots or on the top of soil cells installed under the new sidewalk depending on the existing root locations. See Suspended Pavements article for more information.
⊙ Site – New trees and preserve existing trees
Two Best Planting Options – Excavate as much soil as possible, under and around any existing roots, including the areas where the pavement is planned. Carefully examine the existing roots and prune if necessary. Follow the Stockholm Solution procedures of adding layers of large rock, washing soil into the voids between the rocks, adding another layer of rocks, and continuing the process until the entire area that will become paved, is just below finished grade. An option would be to install CU Structural Soil which consists of mixing stone and soil together and installing this mix into the area to be paved. After completing either option, add any new trees and root barriers as necessary, before finishing the job with the addition of a new pavement on the surface.
⊙ Site – New trees and preserve existing sidewalks
Best Planting Option – Consider relocating the planting site to the other side of the sidewalk, away from the curb and street, if the site is suitable and better soil is available. This assumes that the traffic volume and speed are not a pedestrian safety concern. This option may require a local easement or agreement with the abutting land owner if the trees will be planted on private property. In cities where this option is approved, the maintenance of the tree is also transferred to the private land owner. See more information.
Second Best Planting Option – Excavate as much soil as possible to obtain 500 cu. ft. (14 cu meters) of good soil, include going as deep as 4 feet (125 cm). Punch holes from the bottom of the planting pit, under the sidewalk, if good soil is available beyond the sidewalk, and let the tree's roots following the holes toward better soil and growing conditions. Select a tree that is suitable for the amount of soil available. See more information and scroll down to the section dealing with soil volume. Plant the tree with excellent soil that is similar in texture to the existing soil around the planting pit.
⊙ Site – No trees and no sidewalks
Best Planting Option – All the planting options listed above are suitable. However, anticipate what the future might bring at this site and plant the appropriate tree at the appropriate site for the future. For more information read the entire article.
⊙ Site – Tree planting options
Best Choice of Trees – Become familiar with how to plant trees that are bare root. They are the least costly to purchase and plant by contract and easiest to plant when using volunteers. When planting them in city soils, the trees will not suffer from the transition to different soil than they were growing in at the nursery. See more information on planting bare root trees. If there is a concern that the lack of a soil ball might cause the tree to blow over, there are several stabilizing options that reduce this concern. See more information on tree stabilization.
The following article has been selected because it is deemed very important to the arboricultural profession
and deserves special recognition. It has appeared in a previous Seminar and because of this it is not eligible for earning certification credits; there is no test at the end of this article.
Tree Planting Options
Edited by Len Phillips
When you are asked to recommend the best way to preserve or plant new trees in the city, how do you respond? The following can be considered the best options for planting trees in conjunction with a city sidewalk in various site and sidewalk conditions. To start, every tree must have a minimum of 2 cubic feet (0.06 cm) of soil for every square foot (0.1 sm) of the future crown projected at maturity or 4 square feet (0.38 sm) of surface area for every inch (2.5 cm) of trunk diameter the tree is expected to attain, and this should be applied to all the options mentioned below.
⊙ Site – New construction including new sidewalks and new trees
Best Planting Option – During construction of new sidewalks, streets, utilities, and buildings – plant all the trees in groups 10 to 20 ft. (3 – 6m) apart or included shrub beds. Be sure to select trees that are not considered surface rooted trees. For lists of shallow rooted and more desirable trees, see the lists in the opening section of this article. Scroll down the page to see the lists.
Second Best Planting Option – The use of soil cells is the next best method for ensuring there is enough suitable soil for a tree to develop into a mature specimen. Soil cells transfer a compacted foundation 3 ft. (1 m) below grade to a surface suitable for a sidewalk, plaza, or light traffic roadway while allowing plenty of ideal soil for growing trees under the surface. The installation of root barriers to deflect roots downward should be included to prevent the tree's roots from causing damage to the surface pavement. The soil cells will also provide stormwater storage and eliminate the need for watering the trees. See more information.
⊙ Site – New sidewalks and preserve existing trees
Best Option – Carefully examine the condition of the tree and the existing roots to provide care, protection, and root pruning as necessary. Modify the sidewalk design and location to accommodate the tree and its roots. This option is often the result of sidewalk replacements caused by roots that have damaged the existing sidewalks. The best and most common solution is to raise the sidewalk higher which results in the roots being in deeper soil than before the new sidewalk is installed. Include S-curves around the trees and pavement alternatives found in this article.
Second Best Option – Loosen and improve soil including that which will serve as a base for pavement. New sidewalks should be built and suspended on pilings above the tree roots or on the top of soil cells installed under the new sidewalk depending on the existing root locations. See Suspended Pavements article for more information.
⊙ Site – New trees and preserve existing trees
Two Best Planting Options – Excavate as much soil as possible, under and around any existing roots, including the areas where the pavement is planned. Carefully examine the existing roots and prune if necessary. Follow the Stockholm Solution procedures of adding layers of large rock, washing soil into the voids between the rocks, adding another layer of rocks, and continuing the process until the entire area that will become paved, is just below finished grade. An option would be to install CU Structural Soil which consists of mixing stone and soil together and installing this mix into the area to be paved. After completing either option, add any new trees and root barriers as necessary, before finishing the job with the addition of a new pavement on the surface.
⊙ Site – New trees and preserve existing sidewalks
Best Planting Option – Consider relocating the planting site to the other side of the sidewalk, away from the curb and street, if the site is suitable and better soil is available. This assumes that the traffic volume and speed are not a pedestrian safety concern. This option may require a local easement or agreement with the abutting land owner if the trees will be planted on private property. In cities where this option is approved, the maintenance of the tree is also transferred to the private land owner. See more information.
Second Best Planting Option – Excavate as much soil as possible to obtain 500 cu. ft. (14 cu meters) of good soil, include going as deep as 4 feet (125 cm). Punch holes from the bottom of the planting pit, under the sidewalk, if good soil is available beyond the sidewalk, and let the tree's roots following the holes toward better soil and growing conditions. Select a tree that is suitable for the amount of soil available. See more information and scroll down to the section dealing with soil volume. Plant the tree with excellent soil that is similar in texture to the existing soil around the planting pit.
⊙ Site – No trees and no sidewalks
Best Planting Option – All the planting options listed above are suitable. However, anticipate what the future might bring at this site and plant the appropriate tree at the appropriate site for the future. For more information read the entire article.
⊙ Site – Tree planting options
Best Choice of Trees – Become familiar with how to plant trees that are bare root. They are the least costly to purchase and plant by contract and easiest to plant when using volunteers. When planting them in city soils, the trees will not suffer from the transition to different soil than they were growing in at the nursery. See more information on planting bare root trees. If there is a concern that the lack of a soil ball might cause the tree to blow over, there are several stabilizing options that reduce this concern. See more information on tree stabilization.