Establishing Maximum Size Expectations for Urban Trees with Regard to Designed Space

Abstract

One issue confronting the application of forest management principles to urban tree canopy management decisions is the lack of data correlating site, tree size, and tree age. Researchers tested whether terminal size (stem diameter) can be linked to site type for informed management and design decisions. Data were considered from eleven New Jersey, U.S. communities. Diameter breast height (DBH) distribution established regionalized service life expectancies of commonly planted species by site type and expected maximum DBH. The goal was to develop a method to identify trees approaching senescence within an inventory. Three common urban landscape site types were used: tree pit, planting strip, and unlimited soil. Thirty-one taxa were present in large enough populations to use in species-specific analysis. The species were classified into small, medium, and large size categories based on published growth expectations. The study authors developed DBH occurrence percentiles, and DBH within the ninety-fifth were described as a maximum size range. There was a significant difference in maximum sizes between planting site types. Regardless of the size class of the tree, the data showed reduced planting space resulted in reduced maximum size.