Fig. 3

Direct or indirect relationship between tree mortality and each of the following factors: SI, age, BAL, DBH, and stand density. Arrows indicate unidirectional effects among variables. The red and black arrows indicate positive and negative effects, respectively. The gray-dotted line indicates non-significant effects (p > 0.05). The values in the figure show the coefficients of each parameter based on the piecewise structural equation model (Table 2)