If the entire crown will not be thinned, the Project Manager or designee must approve and specify the percentage of foliage to be removed. The removal percentage is between ten fifteen percent (10%-15%) percent but should not – exceed 25 percent (25%) of the foliage when pruning to thin methods. Raising Pruning to raise, elevate, or lift a canopy is the selective removal of branches to provide vertical clearance. Crown raising shortens or removes lower branches of a tree to provide clearance for buildings, signs, vehicles, pedestrians, and vistas. Live crown to clear trunk ratio should be no less than 50 percent when raising is completed. Structural pruning should be considered with raising according to ANSI standards. When raising, the desired clearance should be specified by the Project Manager or designee. Branches over paved areas should be shortened or removed to allow approximately 10’ over sidewalks, 16’ over travel lanes, or clearances specified by Project Manager or designee as practical. Over landscape areas and sidewalks, the limbs should be shortened or removed to allow for pedestrian and utility use. Trees within planting beds, an 8 foot clearance is required or as directed by the Project Manager or designee. Shortening of branching is the desired method of attaining adequate clearance. When pruning is completed, approximately one-half of the foliage should originate from branches on the lower two-thirds of each tree. Reducing Pruning to reduce is the selective removal of branches and stems to decrease the height and/or spread of a tree or shrub. This type of pruning is done to minimize the risk of failure, to reduce height or spread, for utility line clearance, to clear vegetation from buildings, or structures, or to improve the appearance of the plant. Portions of the crown, such as individual limbs, can be reduced to balance the canopy, provide clearance, or reduce the likelihood of breakage on limbs with defects. Occasionally, the entire crown is reduced. Reducing or thinning should be considered if cabling would be performed. Crown reduction should be accomplished with reduction cuts, not heading cuts. 2. Structural Tree Pruning Structural tree pruning is the removal of live branches and stems to influence orientation, spacing, growth rate, strength of attachment, and ultimate size of branches and stems. The removal percentage is between 25 50 percent depending on the tree type. The structural – pruning includes all basic tree pruning techniques listed below.
If the entire crown will not be thinned, the Project Manager or designee must approve and specify the percentage of foliage to be removed. The removal percentage is between ten – fifteen percent (10%-15%) percent but should not exceed 25 percent (25%) of the foliage when pruning to thin methods. Raising Pruning to raise, elevate, or lift a canopy is the selective removal of branches to provide vertical clearance. Crown raising shortens or removes lower branches of a tree to provide clearance for buildings, signs, vehicles, pedestrians, and vistas. Live crown to clear trunk ratio should be no less than 50 percent when raising is completed. Structural pruning should be considered with raising according to ANSI standards. When raising, the desired clearance should be specified by the Project Manager or designee. Branches over paved areas should be shortened or removed to allow approximately 10’ over sidewalks, 16’ over travel lanes, or clearances specified by Project Manager or designee as practical. Over landscape areas and sidewalks, the limbs should be shortened or removed to allow for pedestrian and utility use. Trees within planting beds, an 8 foot clearance is required or as directed by the Project Manager or designee. Shortening of branching is the desired method of attaining adequate clearance. When pruning is completed, approximately one-half of the foliage should originate from branches on the lower two-thirds of each tree. Reducing Pruning to reduce is the selective removal of branches and stems to decrease the height and/or spread of a tree or shrub. This type of pruning is done to minimize the risk of failure, to reduce height or spread, for utility line clearance, to clear vegetation from buildings, or structures, or to improve the appearance of the plant. Portions of the crown, such as individual limbs, can be reduced to balance the canopy, provide clearance, or reduce the likelihood of breakage on limbs with defects. Occasionally, the entire crown is reduced. Reducing or thinning should be considered if cabling would be performed. Crown reduction should be accomplished with reduction cuts, not heading cuts. 2. Structural Tree Pruning Structural tree pruning is the removal of live branches and stems to influence orientation, spacing, growth rate, strength of attachment, and ultimate size of branches and stems. The removal percentage is between 25 – 50 percent depending on the tree type. The structural pruning includes all basic tree pruning techniques listed below.
TREE-MAINTENANCE-CCONTRACT-FY-2017-2018-Final.docx