Fig. 4
Initial structural equation model with variables and residual errors (ei). The variables of the tree growth and management models are our measurements from field investigations. The variables of the environmental model are the seven most contributed ones (Table 1). The variable number (seven) is the same as the variable number of the tree growth model to reduce internal variation. As for the productivity, we used the total value (RMB) of raw tea harvested as an indicator. Correlations connected to residual errors were omitted to aid model visualization. Arrows indicating rectangles from ellipses represent observed variables indicating latent variables. Arrows between ellipses represent correlations