Best Management Practices for Successful Urban Tree Plantings
PLANTING AND MAINTENANCE SPECIFICATIONS
Best Management Practices (BMPs) for successful landscape tree establishment in the urban environment depends on the design, site analysis, tree species selection, and proper planting and maintenance. All these factors are interrelated. Compromises to any of the BMPs affects other establishment factors and results in stress to the tree with potential death or failure of the planting. Each factor will be highlighted separately but keep in mind that all factors are evaluated with attention to the other three factors.
Once the proper tree has been selected to fit the site and the landscape design, proper planting and follow-up care are required for the success of the project. The following points should be considered during the planting process:
Trees are transported to the site in a covered vehicle that prevetns wind and termperature extremes.
Plants should be well watered prior to shipping and checked for moisture at arrival.
On site plant material is maintained under shade and irrigated twice daily. Plants are healed-in if B&B material is used.
Trees should be protected from extreme temperatures, freezing or extreme heat.
Always handle tree by the root ball using straps or powered equipment and do not lift using branches or the trunk. The trunk should be wrapped during shipping and the planting process for protection.
Inspect roots of container trees and remove any large roots that are circling over 1/3 of the root ball especially in the upper 2 to 3 inches of the root ball. Removing very large roots can result in excessive stress and possible death of the tree.
The hole should be dug 2 to 3 times wider than the root ball to allow easy access by the roots into the surrounding soil and no deeper than the root ball.
Rough-up or score sides of the hole to prevent glazing or compaction of planting hole and potential obstruction of lateral root growth.
Most urban soils are compacted and poorly drained resulting in low oxygen for the roots. Plant the tree with the root ball top at least 1 to 3 inches above the soil line with the trunk flare/root flare and uppermost roots at least level with the backfill surrounding the tree.
Soil removed from the hole makes the best backfill unless the whole planting area can be amended uniformly. There is no apparent benefit from root stimulants, water absorbing gels, mycorrhizae or fertilizer at planting. Planting site should be fertilized according to Soil Test recommendations for long term health of the tree.
Gradually straighten the tree as backfill is added.
Remove synthetic wraps, rope, twine from the tree and ball. Wire baskets should be removed when possible but research and practical application allows for removing at least the top 2 to 3 rungs of the basket. Although wire does not deteriorate, roots grow to encapsulate wire without apparent damage.
Slice a shovel or spade around the backfill to settle the soil and remove air pockets. Break up heavy clay clods. Do not step firmly on the backfill which may cause excessive compaction.
Irrigate with 10 to 20 gallons of water to the root ball and surrounding soil. Apply 2 to 3 inches of mulch to the edge of the root ball extending 6 to 8 feet from the tree. A thin layer of mulch (1/2 inch) can be applied to the root ball area for aesthetics. Do not pile much against the trunk of the tree.
Only a thin layer of mulch and no soil should be on the top of the original root ball allowing the roots surrounding the root ball to be on the surface and water to penetrate into the root ball.
Stake the tree if the planting is in a windy area or an area of high traffic. If the tree is leaning due to lack of taper or strength, tree selection was improper. Many trees with heavy root balls do not need staking.