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Tree Report, 218 Ray Street, Pleasanton February 12, 2020 Ed Brennan, Consulting Arborist Page 3 Suitability for Preservation Before evaluating the impacts that will occur during development, it is important to consider the quality of the tree resource itself, and the potential for individual trees to function well over an extended length of time. Trees that are preserved on development sites must be carefully selected to make sure that they may survive development impacts, adapt to a new environment and perform well in the landscape. My goal is to identify trees that have the potential for long-term health, structural stability and longevity. For trees growing in open fields, away from areas where people and property are present, structural defects and/or poor health presents a low risk of damage or injury if they fail. However, we must be concerned about safety in use areas. Therefore, where development encroaches into existing plantings, we must consider their structural stability as well as their potential to grow and thrive in a new environment. Where development will not occur, the normal life cycles of decline, structural failure and death should be allowed to continue. Evaluation of suitability for preservation considers several factors: ■ Tree health Healthy, vigorous trees are better able to tolerate impacts such as root injury, demolition of existing structures, changes in soil grade and moisture, and soil compaction than are non -vigorous trees. • Structural integrity Trees with significant amounts of wood decay and other structural defects that cannot be corrected are likely to fail. Such trees should not be preserved in areas where damage to people or property is likely. ■ Species response There is a wide variation in the response of individual species to construction impacts and changes in the environment. In our experience, for example, Calif. black walnut is sensitive to construction impacts, while coast is tolerant of site disturbance. IN Tree age and longevity Old trees, while having significant emotional and aesthetic appeal, have limited physiological capacity to adjust to an altered environment. Young trees are better able to generate new tissue and respond to change. The potential longevity of the Monterey pines is low because of the mature age and infection with pitch canker. Table 3: Tree Dripline Measurements Tree No. Species Trunk diameter Dripline Measurements (feet) (inches) North South East West 1 Bradford pear 11 8' 6' 8' 8' 2 Bradford pear 7 7' 5' 7' 8' 3 Bradford pear 6 4' 5' 6' 4' 4 Bradford pear 9 9' 8' 9' 8' 5 Bradford pear 10 12' 11' 11' 9' 6 Valley oak 6 4' 5' 0' 5' 7 Pecan 25 27' 21' 25' 24' Suitability for Preservation Before evaluating the impacts that will occur during development, it is important to consider the quality of the tree resource itself, and the potential for individual trees to function well over an extended length of time. Trees that are preserved on development sites must be carefully selected to make sure that they may survive development impacts, adapt to a new environment and perform well in the landscape. My goal is to identify trees that have the potential for long-term health, structural stability and longevity. For trees growing in open fields, away from areas where people and property are present, structural defects and/or poor health presents a low risk of damage or injury if they fail. However, we must be concerned about safety in use areas. Therefore, where development encroaches into existing plantings, we must consider their structural stability as well as their potential to grow and thrive in a new environment. Where development will not occur, the normal life cycles of decline, structural failure and death should be allowed to continue. Evaluation of suitability for preservation considers several factors: ■ Tree health Healthy, vigorous trees are better able to tolerate impacts such as root injury, demolition of existing structures, changes in soil grade and moisture, and soil compaction than are non -vigorous trees. • Structural integrity Trees with significant amounts of wood decay and other structural defects that cannot be corrected are likely to fail. Such trees should not be preserved in areas where damage to people or property is likely. ■ Species response There is a wide variation in the response of individual species to construction impacts and changes in the environment. In our experience, for example, Calif. black walnut is sensitive to construction impacts, while coast is tolerant of site disturbance. IN Tree age and longevity Old trees, while having significant emotional and aesthetic appeal, have limited physiological capacity to adjust to an altered environment. Young trees are better able to generate new tissue and respond to change. The potential longevity of the Monterey pines is low because of the mature age and infection with pitch canker.