Tree Protection Requirements During Construction

The area around the tree, extending up to a distance equal to 10 times the trunk diameter, is considered the Tree Protection Zone (TPZ) because it provides most of the elements the tree needs to survive and remain stable. The following activities are prohibited within the TPZ unless approved by the City Arborist (SMMC 13.40.080#(b)(5)):

(A) Excavation, grading, soil deposit, drainage, and leveling.

(B) Disposal or depositing of oil, gasoline, chemicals, paints, solvents, or other materials within the TPZ or in drainage channels, swales, or areas that may lead to the Dripline.

(C) Soil Compaction from heavy machinery and vehicles, storage of materials, structures, paving, etc.

(D) Trenching or excavation to provide irrigation, utility lines, services, pipe, drainage, or other improvements below grade.

(E) Storage of any materials or equipment of any kind.

(F) Parking or driving vehicles or self-propelled equipment.

Tree image

Tree Protection Plan

If construction activities cannot be kept outside of the TPZ of protected trees, a Tree Protection Plan from an ISA Certified Arborist will be required. Construction activities mean building, demolition, grading, excavation, or paving, but also include any work that may not be shown on the plans, like storing or staging of materials, site access, parking, placement of temporary structures, debris disposal, additional excavation, landscaping, etc. (SMMC 13.40.030#(g)).

It is the responsibility of the Applicant and the Project Arborist to verify the requirements of a TPP and ensure that all submitted information is consistent to prevent delays. Use the Arborist Report and Tree Protection Plan Checklist for assistance.

When the TPP is sufficient to prevent harm from foreseeable construction activities, it shall be approved along with the construction plans submitted for revision. However, a building permit will not be issued until tree protection is installed to ensure that no trees are damaged.

The approved construction plans shall include all protected trees with the proposed protection measures drawn at scale. Additionally, the last version of the Arborist Report and TPP must be inserted in the plans for reference (SMMC 13.40.080#(b)(4)). Important elements to be included are as follows:

  • All Protected trees identified with the same number or tag used in the Arborist report and TPP. Trees proposed to be removed shall be marked with an "X" or ghosted out.
  • TPZs drawn to scale around all trees impacted by development (including neighboring trees and street trees if applicable).
  • Accurate location of fencing using dash-lined symbology. 
  • Accurate location of trunk wraps and root protection when fencing is not feasible. 
  • The location of areas of hand excavation (or other types like pressurized air, or water).
  • The location of areas or specific activities where monitoring by the Project Arborist is needed.

Sample of an Arborist Report Included in the Plan Set

Sample of an Arborist Report Included in the Plan Set

Tree protection measures must be installed before commencing construction work, including activities such as demolition or site preparation. A building permit cannot be issued until it is verified that protection measures are properly installed. Failing to comply with the approved TPP is illegal and may result in stop-work orders, Protected tree violations, and penalties as described in SMMC 13.40.160. 

Approved Protective Measures

The following are the approved protective measures in the City. These detail sheets can be downloaded and inserted directly into the project plans from this link.

Trees - Type I Complete Protective Fencing

Type I Complete Protective Fencing

Fencing shall consist of chain link fence (6 feet high), mounted on galvanized iron posts wit 2 inches in diameter. Each post must be driven into the ground at least 2 feet deep, no more than 10 feet apart. The fence shall enclose the entire TPZ of the tree(s) to be protected throughout the life of the construction project.

Trees - Type II Partial-Reduced Fencing

Type II Partial/Reduced Fencing

The fence encloses part of the TPZ but the soil and root zone are protected with root buffers or existing hardscape not planned to be demolished. For trees situated within the street planting strip, only the planting strip and yard side of the TPZ shall be enclosed with the required chain link fencing to provide public use of the street and sidewalk.

Trees - Type III Trunk Wrap
Trees - Root Buffer

Type III Trunk Wrap 

(to be used with Root Buffer when construction activities cannot be kept outside of the TPZ)

Wrap the trunk with orange plastic fencing for buffering (2" thick). Overlay orange plastic fencing with 2-inch thick wooden slats bound securely by two layers of additional orange fencing (slats shall not be allowed to dig into the bark). During installation, use caution to avoid damaging any branches. Major limbs may also require wrapping. Straw wattle can be used as an alternative material. For this purpose coil the straw wattle around the lowest 6' of the trunk and secure it with a double layer of orange fence or similar material.

Type IV Root Buffer

(to be used with Trunk Wrap when construction activities cannot be kept outside of TPZ)

The root buffer shall consist of secured geotextile material covering the area to be protected. Cover the geotextile material with 4 to 6 inches of clean wood chips. Securely install 3/4-inch plywood over the wood chips. The root buffer shall be installed and removed without wheeled equipment touching exposed soil. This means some or all the work should be done by hand.

Monitoring and Compliance

Periodic monitoring is required to verify the project's compliance with the TPP. An estimated schedule of inspections by the Project Arborist will be required as a condition of approval for construction projects. After each inspection, a letter documenting the condition of trees and/or reporting any damages must be submitted to the Building Division.