Figures (6)  Tables (2)

    • Figure 1. 

      Study area showing the locations of individual tree surveys and the number of individual trees surveyed at different elevation gradients.

    • Figure 2. 

      Horizontal structural indices for the four nearest neighboring trees around the focal P. armandii tree. Here, α denotes the parameter for calculating the uniform angle index, and 'Distance' represents the distance from a neighboring tree to the focal P. armandii. The trees in the diagram are for illustration purposes only and do not represent specific species.

    • Figure 3. 

      Distribution of continuous variables that showed significant effects on infestation probability between the infested and non-infested groups in univariate analysis.

    • Figure 4. 

      Proportional distribution of categorical variables that showed significant effects on infestation probability between the infested and non-infested groups in univariate analysis. The figure shows, for each category of every categorical variable, the proportion of infested trees among all infested trees, and the proportion of non-infested trees among all non-infested trees.

    • Figure 5. 

      Predicted probability distribution of trees in the 'Healthy' or 'Diseased' state under different variable conditions, with the total probability across all variables summing to 100%.

    • Figure 6. 

      Statistical data for the nearest neighbors of P. armandii trees, grouped by different elevation levels, slope aspects, and slope gradient categories. The species proportions within each independent terrain classification interval are sorted in descending order of tree species count, though a higher proportion does not necessarily represent a higher number of trees. (a) The top 5 neighboring trees with the highest proportions in different elevation ranges. (b) The top 5 neighboring trees with the highest proportions in different slope gradient ranges. (c) The top 5 neighboring trees with the highest proportions under different slope aspect conditions.

    • Variable Diseased_Mean ± std (SE) Healthy_Mean ± std (SE) p-value Significance
      DBH (cm) 16.94 ± 6.37 (0.17) 15.00 ± 5.46 (0.21) < 0.001 Significant
      Height (m) 12.27 ± 2.81 (0.08) 11.53 ± 3.69 (0.14) < 0.001 Significant
      Elevation 1752.50 ± 134.58 (3.61) 1699.28 ± 113.81 (4.44) < 0.001 Significant
      Slope 17.40 ± 5.82 (0.16) 18.99 ± 6.85 (0.27) < 0.001 Significant
      Slope aspect 100.01 ± 84.77 (2.27) 106.64 ± 88.89 (3.47) 0.110 Not significant
      Openness, O 0.30 ± 0.18 (0.00) 0.27 ± 0.15 (0.01) 0.002 Significant
      Nearest non-Pinus armandii distance 1.81 ± 1.40 (0.04) 1.67 ± 1.28 (0.05) 0.029 Significant
      Uniform angle index, W 0.00: 7.33% 0.00: 8.07% 0.245 Not significant
      0.25: 17.11% 0.25: 14.61%
      0.50: 44.57% 0.50: 47.95%
      0.75: 19.34% 0.75: 16.95%
      1.00: 11.65% 1.00: 12.79%
      Mingling, M 0.00: 12.51% 0.00: 7.91% 0.010 Significant
      0.25: 21.21% 0.25: 19.33%
      0.50: 27.10% 0.50: 28.92%
      0.75: 25.81% 0.75: 27.25%
      1.00: 13.37% 1.00: 16.59%
      DBH dominance 0.00: 37.10% 0.00: 26.94% < 0.001 Significant
      0.25: 28.97% 0.25: 28.92%
      0.50: 18.76% 0.50: 24.66%
      0.75: 9.78% 0.75: 14.00%
      1.00: 5.39% 1.00: 5.48%
      Height dominance 0.00: 35.80% 0.00: 27.85% < 0.001 Significant
      0.25: 29.26% 0.25: 28.01%
      0.50: 19.19% 0.50: 23.19%
      0.75: 10.14% 0.75: 14.00%
      1.00: 5.61% 1.00: 6.85%
      For categorical variables, values are fixed at 0, 0.25, 0.5, 0.75, and 1, with respective proportions reported.

      Table 1. 

      Grouped statistics and significance test results.

    • Variable β p-value Odd Significance
      Constant −5.205 < 0.001 0.005 Significant
      DBH (cm) 0.044 0.003 1.045 Significant
      Height (m) 0.023 0.422 1.023 Not significant
      Openness, O 1.523 < 0.001 4.584 Significant
      Nearest non-Pinus armandii distance −0.085 0.138 0.919 Not significant
      Elevation 0.003 < 0.001 1.003 Significant
      Slope −0.020 0.026 0.981 Significant
      Mingling, M −0.782 0.001 0.457 Significant
      DBH dominance −0.155 0.62 0.856 Not significant
      Height dominance 0.133 0.666 1.143 Not significant

      Table 2. 

      Logit regression model results.