View Full Version : Best Management Practices for Successful Urban Tree Plantings

04-19-2007, 05:07 AM
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 affect other establishment factors and result 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:

High quality plant material is maintained on the site under shade and with twice daily irrigation. 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. (Remove after planting)
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.

Most urban soils are compacted and poorly drained resulting in low oxygen for the roots. Plant the tree with the roots 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.

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 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. Do not pile mulch 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.

Maintenance Requirements for Successful Tree Planting

Trees provided with regular irrigation, 3 times per week, for the first growing season will stimulate greater root growth. Establishment period is about 6 months for each inch tree caliper (ex. 3” caliper = 18 month establishment period)
Two to three gallons of water is required for each caliper inch of tree. Irrigation is applied to the root ball. If root ball is wet, do not irrigate.

Pruning should have been done at the nursery. No pruning for the first year after planting. Pruning can inhibit root growth and establishment.
Maintain 8’ mulch area surrounding tree and limit traffic to prevent compaction.

No grass or weeds are allowed close to the trunk.

Inspect planted trees to be sure they were not planted too deep and root flare is distinctly visible.

Remember to remove all stakes after first year.

Pruning is required after year 2 to remove lower limbs to lift canopy and maintain central leader, limb spacing and arrangement of limbs on the central trunk. Proper pruning cuts are required, (no flush cuts!).

Trees respond to fertility after year one primarily to Nitrogen (N) at a rate of 3 to 5 pounds of N per 1000 ft. If phosphorus and potassium have been adjusted to a medium level or better, those nutrients should be sufficient. A split application of fertilizer in winter and again in mid June should result in maximum growth potential.