§ 106.39.040. Arborist's Report

A Tree Permit application involving one or more live trees shall include an Arborist's report, in compliance with the following requirements, where determined by the Director to be necessary based on the number, type, and locations of trees on the site.

A.

Minimum information. The Arborist's report shall include the following information:

1.

Botanical name of trees by tree number;

2.

Common name of trees by tree number;

3.

Location of trees by tree number;

4.

Diameter at 54 inches above the ground, by tree number;

5.

Height by tree number (optional);

6.

Protected zone radius by tree number (measure longest radius);

7.

Condition (structure and vigor as described below) by tree number;

8.

Construction impacts; and

9.

Recommendations.

B.

Determination of tree condition. The information on tree condition in the report shall be developed as follows:

1.

Rating system. The condition of each tree is to be considered when determining a tree's rating according to the following categories: excellent (it is rare that a tree qualifies in this category); good; fair to good; fair; fair to poor; or poor.

2.

Factors to be considered. At least the following factors shall be considered in light of the trees life expectancy under existing and planned conditions when determining a tree's rating:

a.

The condition and environment of the tree's root crown (also roots, if applicable);

b.

The condition of the trunk, including decay, injury callusing or presence of fungus sporophores;

c.

The condition of the limbs, including strength of crotches, amount of deadwood, hollow areas, and whether there is excessive weight borne by them;

d.

The condition and growth rate history of the twigs, including pest damage and diseases;

e.

Leaf appearance, including abnormal size and density as well as pest and disease damage; and

f.

The dripline environment, including evidence of grade changes and presence of water courses or ponding.

3.

Formulation of tree condition. Using an averaging of the above factors together with the Arborist's best judgment, the tree shall be described using the above rating categories. It is important to rate structural condition separately from the tree's vigor condition if they are different. Root crown, trunk and limb ratings relate most to structure, while twigs and foliage, including growth rate, relate most to vigor. The structure of the root crown-trunk area is of primary importance and takes precedence over any other factor. This information should not be considered to be a formula but simply a guideline to help describe a tree's condition.

C.

Arborist's recommendations. The Arborist's recommendations shall be developed in compliance with the following:

1.

Recommendations by tree number. Based upon the conditions and findings, recommendations should be made that logically follow the report conditions. For instance, if weak crotches are reported, cabling would be a logical recommendation to include in the report. These recommended mitigative measures should be spelled out and in some cases may even improve the tree's condition ratings.

2.

Preservation measures for each tree not being removed. The specific recommendations must consider the impacts from the activities proposed.