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Tree Report, Vineyard Townhome Condominiums Pleasanton, CA September 15,2005 HortScience, Inc. Page 4 . 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 Iikeiy. . 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 walnuts are difficult to preserve, They rarely recover from injuries to the root system. Valley oaks have a moderate tolerance to site disturbance. In contrast, Canary Island pine western sycamore are quite tolerant of site disturbance. . 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 belter able to generate new tissue and respond to change. Each tree was rated for suitability for preservation based upon its age, health, structural condition and ability to safely coexist within a development environment (Table 2). We consider trees with good suitability for preservation to be the best candidates for preservation. We do not recommend retention of trees with poor suitability for preservation in areas where people or property will be present. Retention of trees with moderate suitability for preservation depends upon the intensity of proposed site changes. Table 2: Tree Suitability for Preservation Good These are trees with good health and structural stability that have the potential for longevity at the site. Eight (8) trees were rated as having good suitability including 3 Heritage trees. Tree No. Species Diameter (in.) Heritage Tree? 9 10 11 18 21 27 38 57 Valley oak Valley oak Valley oak Coast live oak Valley oak Canary Island pine Canary Island pine Valley oak 6,5 8,4 9,4,2 5 12 15 17 25 No No No No No Yes Yes Yes