Fig. 3
From: Species diversity and spatial pattern of heritage trees in Taiyuan
Redundancy analysis (RDA) ordination illustrating the relationship between the species diversity and tree abundance of heritage trees and environmental factors in Taiyuan. Solid arrowheads represent the dependent variables (species diversity and tree abundance), while hollow arrowheads denote the independent variables (environmental factors). The angle between the arrows indicates the nature of the correlation: an acute angle denotes positive correlation, an obtuse angle negative correlation, and a right angle no correlation. The hollow dots represent various districts within Taiyuan and refer to Table 1 for the meaning of district abbreviations.
