Development Services
An arborist report is a required document in the submittal package for most new development projects in the Puget Sound area. This report provides a detailed assessment of the trees on or adjacent to the site, their health, and their regulation status. An arborist report outlines recommendations for tree management and preservation to meet tree retention goals.
Construction Monitoring
Work within the critical root zone of retained trees is not generally advisable due to the likelihood of causing damage to a large portion of the tree's root system.
The International Society of Arboriculture defines Critical Root Zone (CRZ) as an area equal to a one-foot radius from the tree’s trunk per inch of the tree’s diameter at 4.5 feet above grade. The CRZ may vary from the distance from the trunk that impacts might occur without compromising the tree's health or structural stability. This measurement is based on species, age, condition, existing improvements, and the anticipated overall impacts on the subject tree. These 'Limits of Disturbance' (LoD) measurements can be included in an arborist report and may be referenced when determining whether or not a tree can be successfully retained with specified tree protection measures implemented.
When work must occur within the CRZ of retained trees, an urban forester trained in root zone conflicts can provide valuable tree retention services. We can identify and document the extent of root disruption that will occur and whether the tree is likely to remain viable or become destabilized following construction activity.
A certified arborist on the construction team is required by many planning departments when working within the CRZ of retained trees.
Tree Protection Fencing
Root Zone Impact Assessment
