Tree Decline Due to Improper Planting Depth

In years past improper planting techniques were extremely widespread, causing the death of many a transplanted tree. Unfortunately, in spite of the educational efforts of those in the field of Arboriculture, improper techniques are in practice today. Some studies have found 93% of excavated trees had excessive soil or other material covering the root collar. Trees that are buried too deeply look like telephone poles sticking out of the ground, with no visible root flare (the area where the trunk begins to widen at the base of the tree). Many trees planted in this manner will not survive for more than two years, though some will survive in a stressed and weakened state for fifteen to twenty years before they exhibit symptoms of decline.

Remediation for Trees Planted Too Deep

For recently planted trees (i.e. less than two to three months with warm soil temperatures for root growth), the greatest long-term benefit will be achieved by replanting the tree at the proper depth.

For partially established trees, replanting will cause additional stress, therefore the benefits of replanting must outweigh the risks. The tree must be in good enough health to survive the additional stress of replanting. A tree already showing signs of serious decline would probably not survive the replanting procedure.

For larger, fully established trees, root collar excavation to remove the excess soil or other materials in contact with the trunk will reduce the possibility of basal and collar rot diseases and will improve aeration to the structural roots at lower depths. Removing soil near the trunk may also expose and allow for removal of “misdirected” roots before they become girdling roots.

Information Sources: U of I Extension, IAA Illinois Trees Volume XVI Number IV, Morton Arboretum, Feature Article by Gary Watson

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