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136 | CITY OF PLEASANTON URBAN FOREST MASTER PLAN STATUS OF THE URBAN FOREST PUBLIC AND PRIVATE TREES Table 2-11. Tree Conditions by Tree Age of the Pleasanton Inventory Age Category Tree Condition - # of Trees (% of Total Age Category) Good Fair Poor Critical Dead Total Immature 1,468 (22%)4,763 (73%)191 (3%)36 (1%)93 (1%)6,564 Young 1,080 (9%)10,614 (88%)341 (3%)29 (0.2%)52 (0.4%)12,144 Middle-aged 179 (7%)2,382 (87%)133 (5%)20 (1%)14 (1%)2740 Mature 206 (9%)1,841 (83%)136 (6 %)23 (1%)6 (0.3%)2219 Because tree condition ratings are qualitative, a single tree’s rating may differ depending on each inventory arborist. While the 2024 inventories were not conducted by the same individuals, it can be useful to broadly compare the findings. The Relative Performance Index (RPI) can help identify species that are doing well or those that may need further analysis and management recommendations to improve vigor. RPI is calculated by dividing the percentage of trees in a single species that were categorized in good condition and by the percentage of all trees in the inventory that were in good condition. Species with an RPI of 1 or higher are performing as well or better than the entire population. Species with an RPI less than 1 are performing below the entire population (Table 2-12). A sustainability goal that the City should strive for is for all six of the most common species to have higher RPI scores than the average of all species in the public tree inventory (RPI of 1.0 or higher). This could be achieved through a number of strategies including using a strategic planting plan to guide the selection of the appropriate tree species type and size for a given planting site, by including structural pruning of young trees into the establishment care program which should help improve structure as the tree matures, and in drought years, implementing a supplemental watering program for those trees that seem to be most affected.