Predictive equations for dimensions and leaf area of coastal Southern California street trees

Abstract

Tree height, crown height, crown width, diameter at breast height (dbh), and leaf area were measured for 16 species of commonly planted street trees in the coastal southern California city of Santa Monica, USA. The randomly sampled trees were planted from 1 to 44 years ago. Using number of years after planting or dbh as explanatory variables, mean values of dbh, tree height, crown width, and leaf area responses were modeled using two equations. There is strong correlation (adjusted R2 > 0.70) between dbh as a function of number of years after planting, and total height, crown diameter, and leaf area as a function of dbh. Correlation is weaker between measures of crown height and dbh. This is probably due to crown pruning increasing the variability among measurements for trees having the same or similar dbh. Equations for less-intensively pruned species displayed adjusted R2 greater than 0.70. Equations are presented for predicting dimensions and leaf area and applied to compare tree sizes and growth for all species 15 and 30 years after planting.