STREET AND PARK TREES OF BOSTON - A COMPARISON OF URBAN FOREST STRUCTURE

This paper evaluates the structure of street and park trees in Boston' s neighborhoods of Roxbury and North Dorchester. The general hypothesi s is that forest structures of two components of the public urban fore st, street and park trees, are significantly different such that they may warrant different policy and management strategies. Data from an i nventory of the neighborhoods in 1988-1989 include species, diameter a t breast height, and condition of each tree. Descriptive variables cal culated from the data include species diversity, size class diversity, percentage of the tress that are in good condition, and species impor tance lists. From the descriptive variables, size class diversity is g reater for street than for park trees. Species diversity and percentag e of trees in good condition are greater for park than for street tree s. Results from chi-square analyses on tree condition, size class cate gories, and size class categories for Acer platanoides and Quercus rub ra for Condition Class 3 all reject the null hypothesis that street an d park tree populations are distributed similarly. A comparison of the importance lists that include the species that collectively make up 7 5% of all individuals and total basal area shows that there are only s even species required to reach that percentage for street trees, and 1 4 for park trees. At the 75% level, all species that make up at least 5% of all individuals and total basal area are included. Of the seven tree species on the importance list for street trees, only one is a me mber of the presettlement forest and all are tolerant of urban environ mental stress. For park trees, over half of the 14 species on the impo rtance list are members of the presettlement forest, and at least seve n are tolerant of urban environmental stress. The results indicate tha t street and park trees are distinct populations within urban forests, and hence the processes acting to create these two components of the urban forest resource may also differ.