Modeling Street Trees On A Statewide Basis In New York State

Abstract

Street trees are an integral component of livable, healthy communities providing ecosystem benefits and social and aesthetic amenities. Street tree inventory data provides detailed information about the structure and health of a street tree population and facilitates effective planning and management. Most communities lack an inv entory, however, and the patchwork of data at the state level makes planning and management of urban and community forestry difficult for state officials. This dissertation proposes a methodology using street tree inventory data stratified and weighted by 1990 USDA Plant Hardiness Zone classes to estimate New York State's prevalent street tree species and genera, quantify statewide benefits provided by street trees, and identify statewide trends in the urban forest. Methods used are replicable by other states so officials in those states can obtain similar information. Based on this methodology, Acer was found to be New York State's most prevalent street tree genus and Acer platanoides its most prevalent street tree species. Street tree numbers were estimated for the most prevalent genera and species. Species diversity increased with milder climate, but was found to be insufficient statewide, suggesting vulnerability to invasive pests such as the Asian Longhorned Beetle and Emerald Ash Borer. Analysis of trunk diameter profiles indicated an aging street tree population statewide requiring an increase in new plantings to maintain street tree numbers at current levels. Statistics for the youngest trees revealed increased plantings of small sized tree species relative to plantings of large and medium sized tree species regardless of overhead utility wires and planting location types. Benefits provided per street tree as calculated by i-Tree software did not vary by 1990 USDA Plant Hardiness Zone class, but significant differences were found by zone class in the number of street trees planted per unit of street length . Subsequent to preliminary findings, a number of test street tree inventories were conducted to evaluate whether statistics and trends at the zone class level would be found for the test inventories also. Test inventory statistics did not agree completely with preliminary statistics, but did confirm differences and trends found at the zone class level.