An Analysis of the Street Tree Population of Greater Melbourne at the Beginning of the 21st Century

Abstract

An audit of the street tree population of Melbourne, Victoria, Australia, was undertaken to establish its size and botanical composition as a reference point for future studies. The 31 independent municipalities that comprise metropolitan Melbourne were approached to provide information on their respective street tree populations. Where available, data from individual municipalities on population, area, and total street length were also collected. Of the 31 municipalities surveyed, 23 had undertaken some form of street tree inventory or audit. These individual data sets were combined into a single database. Data queries were then undertaken to obtain a range of information. A total of 922,353 trees, comprising 1127 taxa, were captured in this superset of data. Australian native plants made up the majority of the trees with 60% of the total. Of the Australian native taxa, wattles (Acacia spp.), gums or eucalypts (Eucalyptus spp.), paperbarks (Melaleuca spp.), bottlebrush (Callistemon spp.), and Queensland brush box (Lophostemon confertus [R. Br.] Peter G. Wilson and Waterhouse) comprised 394,730 individuals (43% of all trees). Of the exotic taxa, Prunus spp. were the most common with 86,227 individuals (9% of the total). Queensland brush box was the most common taxon surveyed with 61,959 individuals. Purple-leaf cherry plum (Prunus cerasifera Ehrh. ‘Nigra’) was the most common exotic taxon with 35,402 individuals. An analysis of the diversity of this population showed that it meets a set of minimum diversity criteria apart from the dominance of the Myrtaceae at the family level.