Prior to initiating tree removal and any clearing and grading on the site, trees to be protected and preserved shall be protected from potentially damaging activities as follows unless otherwise approved by the City.
A. Critical Root Zone (CRZ). The CRZ of individual trees, groves, or otherwise designated protected tree areas shall include no less than the area of a circle with a radius that extends one foot out from the tree for every inch of trunk d.b.h., or the area of a circle with radius extending from a tree’s trunk to a point no less than the end of a tree’s longest branch, whichever is greater (see Figure 18.57.090A).
B. Tree Protection Fence (TPF). Before development, the applicant:
1. Shall place three inches of composted woodchips over the CRZ of all retained trees to retain moisture, increase organic matter, and visually establish the CRZ.
2. Shall erect and maintain readily visible protective tree fencing a minimum of three feet beyond the outer edge of the CRZ for all individual trees, groves, or other designated protected tree areas.
a. Fencing shall completely surround the required tree protection area. The city manager may allow adjustments to placement of the TPF based on an evaluation of the tree, soils, and proposed disturbance.
b. Fencing shall be a minimum of four feet high and may be higher if needed to ensure clear visual delineation. Chain-link fence or orange plastic fence fastened to steel stakes/posts driven securely into the ground shall be required in order to discourage easy movement.
c. Any deviation from the tree fencing methods listed above must be authorized in writing by the city manager in advance.
3. Shall keep the protective fencing in place until the City authorizes the removal or issues a final certificate of occupancy, whichever occurs first.
4. Shall ensure that any landscaping done within the root protection zone subsequent to the removal of the fence shall not disturb existing trees including roots within the CRZ.
C. Placing Materials Near Tree. During development, no individual, partnership, corporation, association, organization, cooperative, public or municipal corporation, or agency of any governmental unit, however designated, may conduct any activity within the TPF of any tree designated to remain, except as specified in this section.
D. Attachments to Trees. During development, no individual, partnership, corporation, association, organization, cooperative, public or municipal corporation, or agency of any governmental unit, however designated, shall attach any object to any tree designated for protection.
E. Grade.
1. The grade shall not be filled or cut within the CRZ of any tree designated to remain without prior review by a qualified tree protection professional and advance, written approval from the city manager.
2. The applicant shall not install an impervious surface within the protective barrier of any tree designated to remain without the advance, written authorization of the city manager.
3. To the greatest extent practical, utility trenches shall be located outside of the root protection zone of trees to be retained. Boring or tunneling under the CRZ may be considered an alternative, but shall require the advance, written approval of the city manager.
4. Trees and other vegetation to be retained shall be protected from erosion and sedimentation.
F. Additional Requirements. The city manager may require additional tree protection measures which are consistent with accepted urban forestry practices.
Figure 18.57.090A Critical Root Zone. |
This section shows a cross-section of the typical root zone for a deciduous tree. Eighty-five percent of the tree’s roots are within the top 18 inches of the soil. Roots typically spread up to two times the height of the tree and sometimes more. However, the critical mass of roots is usually found within the critical root zone.
(Ord. 11-0329 § 3 (Exh. 1); Ord. 22-0547 § 4 (Exh. B(II)); Ord. 23-0593 § 4 (Exh. B))