Item 11 - Urban Forest Management Plan

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5 Section 2: Tree Inspections/ Tree Inventory A. Inspection Objectives Inspection of city trees shall identify visually obvious problems, their relative risk, and provide a recommendation for a risk assessment if an immediate risk is identified. The inspection interval should be no greater than five years as part of a routine trimming program. Additionally, supplemental inspections and risk assessments should be done in between trim cycles to track potential tree failures. These can include major arterials, or other highly traveled locations. Inspection and work history data should be tracked and monitored within a tree inventory management program that allows for documented work history to be recorded and accessible. This should include all publicly maintained trees, as determined by the city Arborist. The agency should frequently review the inventory for potential high -risk trees and should assign trees to have risk assessments done with written documentation. Those performing tree inspections must adhere to current industry standards, to ensure they are being done on a consistent and regular manner. ANSI A300 standards and ISA Best Management Practices guide contractors and city staff in tree evaluations with procedures and specifications. B. Identifying and Documenting Inspections Inspected items should include, but are not limited to: 1. Lean/root problems: for example, leaning trees with roots heaving out of the ground. 2. Co-dominant or multiple trunks: competing stems that grow bark between a tight crotch union can be weakened areas prone to failure. 3. Trunk cavities, cankers, mushrooms, and decay: these are indicators of potential internal decay of a tree and, if discovered, may require further investigation and mitigation. 4. Cracks in trunks and branches: these can be indicators of future failures and, if discovered, may require further investigation and mitigation. 5. Weakly attached scaffold limbs and branches: a branch that developed as a reactionary shoot can be predisposed to failure and, if discovered, may require further investigation and mitigation. 6. Hanging or broken branches (hangers): branches that are detached from where they were grown and are hanging and could fall, impacting targets below. Broken branch stubs should be pruned off properly unless preserved for wildlife habitat reasons. 7. Dead branches (deadwood): branches within a canopy of a tree that no longer produce foliage and have begun to lose bark. 8. Pests and other diseases: identified pests that can cause tree failures such as boring, leaf chewing and leaf sucking insects or pathogenic fungus.