Site Plan Review:

Determination of Intent:

Tree Retention Objectives:

• Aesthetics
• Environmental protectums
• Heritage trees

Tree Retention Consideration and Restrictions:

• Species
• Condition
  1. Do not attempt to save large interior forest grown without first determining that trees have clearly gained predominance in their stand and have development large, strong buttress roots, better than average foliage color, proper stem and branch structure with no sign of previous major failure, and a crown-to-stem ratio of at least 50%.

Location and Function:

Cost Effectiveness:

Large tree conservation requires either more space or more money.

Basic Tree Retention Procedure: (see Removal House)

• Identify trees that aren't protected
• Design all phases landscaping of project - from site preperation to final with those excating the trees as the driving force.

Basic Tree Removal Procedure:

• Designate trees for removal
• Decide on disposal: timber, firewood, garbage
• Decide on stump grinding or excavation
• Site and protect all valuable targets
• Employ best means to remove tree

Tree Retention Specification for Development into Forest or Heavily Wooded Landscape:

• Removal of undesirable forest – grown trees near trees.
  1. Identify and establish Optimum Root Zone (ORZ) or Critical Root Zone (CRZ) for retained trees with fence.
• On-site arborist shall designate all trees within forested stands which require topping prior to felling.

Tree Retention Without Grade Change in Open Area:

• Designate ORZ perimeter (circular, square or irregular designation acceptable) around each tree or group of trees and fence with 6' high structure.

Tree Retention Without Grade Change in Confined Area:

• Existing conditions sometimes prevent optimum ORZ perimeter fencing.
• Determine CRZ

Tree Retention With Grade Change inside Optimum Root Zone or Critical Root Zone:

• On-site arborist shall make final decision on all tree retention within areas of grade change.
• Proceed with bulkhead construction as needed.
• Lowering grade around retention tree.
• Raising grade around retention tree.

Tree Retention on Slope:

• Questions regarding slope drainage issues and tree conservation ordinances.
• Measures to provide slope stabilization and proper drainage for construction should also incorporate measures for existing tree retention, if required.
• Slope, construction and drainage.
• Rainwater and gravity.

Tree Retention and Wind:

• This guide should minimize post-construction care and presumes that proper protection measures will remain in place until project completion.

Tree Retention and Water:

• Too much as well as to little water will kill most trees.
• Sudden changes in drainage around large established trees targeted for conservation will stress tree’s root system.
• Any kind of bulkhead construction, whether for roads or building foundations, which traverses a slope uphill of a retention tree will deprive that tree of its normal available water.

Tree Retention and Pavement: Arborist, engineer, paving sub-contractor, landscape architect:

• Ideally every large retained tree on building site would remain untouched, with either mulch or native understory left around its ORZ or CRZ.
• Paved use over roots of retained tree.
• Unit paver method.

Care of Retention Trees:

• Care will depend on analysis by certified and qualified consulting arborists on site both before and after construction to determine what site disturbance has occurred adjacent to retained tree(s).