Statistical analysis
The index used in this paper are per kilometer benefit (PKB, $/km) and
average tree benefit (ATB, $/tree), which indicate the ability of
street trees assemblage and individual street tree for ecosystem
services provision in a specified area respectively. We used PKB instead
of the whole ecosystem services value of a specified area, because the
lengths of different areas are various and the PKB would be more
comparable.
First, we utilized Grouping Analysis (spatial constraints setting is
NO_SPATIAL_CONSTRAINT, and distance method is EUCLIDEAN) in ARCGIS to
categorize the subdistricts for the value of PKB and ATB into 3
categories respectively. Second, we categorized the subdistricts
according to the factors we assumed to have effects on the distribution
of ecosystem services provided by street trees assemblage (population
density, city sprawl and public policy) and do the statistical analysis
in Excel.