APPENDICES - Laserfiche WebLink

5. Trees near buildings (less than 10 feet away) that require drastic pruning to meet fire department vegetation spacing requirements. Tree Replacement When a tree is removed from a property in a WUI area of the City, a proposed replacement should be a tree species appropriate for the conditions on the property. Appropriate species for the WUI areas in the City have the following fire-resistant characteristics (UCANR 2021): • Tree species with leaves that retain moisture. Trees with leaves that retain a greater moisture content are less likely to ignite during a fire. • Open growth structure. Trees with an open growth structure have widely separated branches and limbs that are not likely to accumulate dead leaves or catch embers from a fire. • Raised crown structure. Tree species that naturally prune or shed branches in the lower crown are less likely to retain dead branches in the lower crown and less likely to be ignited by surface fires. • Low litter production. It is normal for all tree species to shed leaves and small branches. However, some species produce low volumes of litter, and those with leaf drop occur during the fall and winter after the fire season has ended. • Drought tolerant. Seasonal and extended droughts are a common occurrence in California. Species adapted to regional weather conditions are less likely to produce excessive leaf litter or dieback when the region experiences persistent hot and dry weather. • Thick Bark. Thick bark trees, particularly tree species native to the region, are more resistant to damage from fire. Thick, persistent bark (e.g., not shedding or peeling) does not readily ignite or spread fire. Other considerations: • Trees planted near electrical lines should be species that do not exceed 30 feet in height when mature. Large shade tree species should not be planted within 50 feet of high-voltage electrical equipment (PG&E 2024). • Identify underground utilities before planting, and do not plant trees within 10 feet of a utility line. • Size at maturity, including the average maximum height and crown spread. Tree replacement in WUI areas should consider the concept of “right tree, right place, right reason” for each site. Right tree, right place emphasizes planting tree species compatible with the region they are growing in and having adequate space to develop without creating hazardous conditions. Trees that are incompatible with the site they are planted in are more likely to be in poor health, have greater maintenance costs, and require early removal (Arbor Day Foundation 2024). In the WUI areas of the city, the “right tree, right place, right reason” includes adequate spacing between newly planted trees and existing vegetation. As noted in the Livermore Pleasanton Fire Department’s vegetation management guidelines, there should be 10 to 40 feet of space between tree crowns, depending on the slope. Planting replacement trees should not only consider whether the species is appropriate for the property but also if the tree will have adequate space between nearby vegetation to minimize the risk of fire transitioning into the tree crown. SubAppendix C contains a list of tree species appropriate for WUI areas in the City of Pleasanton. As a final note, it is not appropriate to replace every tree removed with a new tree in the same location. Poor replanting sites include locations within 10 feet of a structure, within 5 feet of an underground utility line, within 25 feet of an overhead electrical line, and in locations with inadequate spacing between the crowns of the existing mature trees. Replacement trees should be relocated to a more appropriate site in these situations. Watering 20