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Construction site evaluation and preparation

Tree preservation on construction sites

  1. Fence off all areas in root zone that are not needed in construction process. (Root zone = 3x-5x the "drip line", or a circle with radius = tree height.)
  2. Ban traffic except occasional foot traffic in cordoned areas.
  3. Levy meaningful fines for violations
  4. Avoid direct contact with trunk of tree - strap on 2x4 protection if needed
  5. Trench if possible.
  6. Prior to using backhoe,
    • With trencher using dirt teeth cut a ditch 18" from backhoe trench toward tree. Cut roots on tree side of trench with sharp pruning tool or chain saw.
    • Backfill immediately mixing mycorrhizae culture in backfill.


      Backfill immediately and inoculate soil with injector
    • Water trench in dry weather
  7. Cushion root zone to be driven on or used for storage
    • Spread 8-12 inches of chipped wood (available from The Gentle Arborist)
    • Lay plywood for skid steer or tracked equipment to be turned on.
  8. Remove chips after traffic is gone
  9. Inject soil with nutrients, beneficial organisms, and biostimulants/humic acid
  10. ) No pruning of live tissue for 1 year prior to construction, and 1 year after completion.
  11. Hardscapes /parking areas can be built on a plastic pipe/header system imbedded in layers of gravel and geotextile. The tree can be watered and fed through the header system.

This set of guidelines is based on the principles that:

  1. Tree roots need air pores for growth, and pressure on soil collapses and drives out air pores.
  2. A pruned root will likely sprout and thrive; a broken or crushed one will likely die.
  3. Hormones important for root development are produced in the branch tips.
  4. Soil activity beneficial to trees can be increased by introducing known microorganisms.

These procedures will greatly improve survival rate of trees on construction sites, and improve their health and vigor. Consult a qualified arborist as part of your construction project if trees are considered to be part of the final product. Have an arborist on the team.

A tree can add hundreds or even thousands of $$$$$- to property value. Remedial work for damaged tree roots may be ineffective. Removals are costly, property values and expectations suffer.

Copyright 2019 The Gentle Arborist, Inc.