RES 2025054 - Laserfiche WebLink

• For steep slopes over 40 percent: 30 feet of spacing is needed. When planting individual or small groupings of trees, allow for future growth by spacing them 20 to 30 feet apart. In addition, other ladder fuels, such as shrubs, should be removed around the base of trees. Pruning Practices Lack of attention to tree crowns of any species can result in trees accumulating dead twigs, leaves, and branches, regardless of whether they are categorized as "fire resistant." This buildup of dead fuels in the canopy can easily result in trees becoming very flammable. Tree pruning recommendations focus on preventing fire from spreading into a tree canopy. To reduce the fire -spreading potential of trees taller than 18 feet, prune the lower limbs to a minimum height of 6 feet. If the tree is shorter than 18 feet, all branches and foliage should be removed from the lowest 1/3 of the tree. Trees near homes or buildings should receive additional attention, and branches that overhang the roof or come within 10 feet of the chimney should be trimmed or removed (Livermore -Pleasanton Fire Department, 2021). Additional attention should be given to trees that overhang public and private roads by trimming trees to provide 14 feet of vertical clearance above the roadway for emergency vehicle access (CFC, 2022). Special Pruning Standards for Palms Palm trees are significantly different from broadleaf and conifer trees in their pruning requirements. Palm trees lack branches or leaves originating from buds on the trunk; instead, new fronds grow from a central point at the top of the tree (the heart). All palm tree species produce new fronds annually, and certain genera of palms, such as Mexican fan palms (Washingtonia robusta), can accumulate large collars of dead and highly flammable fronds. As a result, palms cannot be pruned usingthe same standards as broadleaf and conifer trees. Pruning practices should emphasize removing dead fronds and skinning the trunk to minimize the accumulation of dead material. Pruning to maintain clearance is generally not necessary unless the tree is near a roof or chimney because live fronds do not readily ignite and removing or damaging the fronds near the heart of the palm can kill the tree. Special Pruning Standards for Species that Produce Large Amounts of Flammable Debris The pruning practices described above address the requirements for trimming and removing flammable branches to create adequate vertical and horizontal spacing. However, some tree species with growth characteristics produce flammable or dead material that is not addressed by pruning branches. Some species of Eucalyptus trees (primarily Eucalyptus degulpta and Eucalyptus globulus) shed their bark in heavy quantities, which produces high volumes of dry and flammable debris at the base of the tree. This pile of bark can readily ignite and spread fire quickly. All dead wood and flammable debris should be removed from the tree before each fire season. Using a Certified Arborist for Pruning An International Society of Arboriculture -Certified Arborist is recommended to complete tree pruning per American National Standards Institute A300 specifications (ANSI, 2017). This will ensure tree pruning complies with wildfire hazard area maintenance recommendations and supports tree longevity. The City of Pleasanton does not require a permit to prune trees; however, pruning should be done in accordance with International Society of Arboriculture pruning guidelines. Topping is not an approved pruning practice as it creates a hazardous canopy with weakly attached limbs prone to failure. Tree Pruning for Utility Clearance Vegetation contact with aboveground electrical equipment is a common cause of fires ignited by electrical utilities. In 2023, contact with vegetation was the cause of 19% of fires ignited by PG&E equipment (CPUC 2024). APPENDIX A -WILDFIRE 20 of 219