During construction, existing trees must be protected in the following manner:
(a) Protective fencing must be provided with an access gate at the Critical Root Zone of protected trees and approved in place by the Director or his designee prior to construction or demolition.
(b) Critical Root Zone must be watered regularly if rainfall of 1 inch per week does not occur during the months of April through October.
(c) No construction staging or disposal of construction materials or by-products including concrete washings, paint, plaster, or chemical solutions is allowed in the Critical Root Zone.
(d) Critical Root Zone should not be subjected to flooding incidental to the construction work.
(e) All work conducted in the ground within the Critical Root Zone of any protected tree should be accomplished with hand tools, unless an air spade is used. Trenches in the Critical Root Zone should be tunneled or completed with an air spade to avoid damage to small feeder roots within the Critical Root Zone.
(f) Where structural footings are required and major roots (over 3 inches in diameter) will be impacted, the engineer of record should submit acceptable footing design alternatives and/or location alternatives to the Director before proceeding.
(g) Any required trenching should be routed in such a manner as to minimize root damage. Radial trenching (radial to tree trunk) is preferred as it is less harmful than tangential trenching. Construction activity should be diverted from the Critical Root Zone. Cutting of roots should be avoided, i.e. the placement of pipes and cables below uncut roots. Whenever possible, and in accordance with applicable code requirements, the same trench should be used for multiple utilities.
(h) Natural or preconstruction grade should be maintained in the Critical Root Zone. Soil should not be in contact with the trunk of the tree above the Basal Flare at any time, during or after construction
(i) In areas where the grade around the protected tree will be lowered, some root cutting may be unavoidable. Cuts should be clean and made at right angles to the roots. When practical, cut roots back to a branching lateral root.
(j) When removing existing pavement in the Critical Root Zone, avoid the use of heavy equipment which will compact and damage the root system.
(k) Mulching materials and methods will be defined by the Director.
(l) Pruning of trees should be in accordance with TCIA standards for pruning.
(Ord. 2009-8. Passed 2-3-09.)