**3. Results**

#### *3.1. Spatiotemporal Changes of Carbon Density*

Carbon density values were mainly explained by the short-wave infrared reflectance (band 7), textures of GLCM and NDSI of Landsat metrics based on the stepwise selection (Table 1). A comparison of observed logarithmic vs. predicted logarithmic carbon values is shown in Figure 2; the coefficients of correlations (adjusted R2) of the full model using all plots were 0.75 for 2009 and 0.71 for 2014. Cross-validation based on 1000 iterations indicated that the 95% CIs of the mean coefficients of correlations were 0.54–0.91 for 2009 and 0.69–0.72 for 2014 (Figure 2).

**Figure 2.** Comparison of observed logarithmic vs. predicted logarithmic carbon values for 2009 (left diagram) and for 2014 (right diagram). Adjusted R<sup>2</sup> values of the full model using all plots were 0.75 for 2009 and 0.71 for 2014. 95% confidence intervals (CIs) of the mean coefficients of correlations were derived from a cross-validation procedure based on 1000 iterations.

Maps indicating the extrapolated carbon densities (Mg/ha) over the entire area of the FMUs for 2009 and 2014 are shown in Figure 3. Mean values (95% CIs) of carbon density (Mg/ha) of Deramakot were 140 (133–151) for 2009 and 170 (162–179) for 2014, while those of Tangkulap were 115 (109–122) for 2009 and 119 (112–126) for 2014 (Figure 3). The mean iterated carbon density value of Deramakot significantly increased from 2009 to 2014 without an overlap in 95% CIs, while that of Tangkulap did not significantly increase and showed a broad overlap of CI (Figure 4).

**Figure 3.** Maps indicating the extrapolated carbon densities (Mg/ha) over the entire area of the three forest managemen<sup>t</sup> units (FMUs) for 2009 (**left**) and 2014 (**right**).

**Figure 4.** Temporal shifts of the mean (95% CI) forest intactness (**a**) and carbon density (**b**) in Deramakot and Tangkulap FMUs from 2009 to 2014. Green symbols indicate Deramakot and red symbols indicate Tangkulap.

#### *3.2. Spatiotemporal Changes of Forest Intactness*

The greatest variance of generic composition occurred along axis 1 of the nMDS ordination (stress values 0.179; Figure S2, Supplementary Materials). Derived nMDS axis-1 scores of plots significantly correlated with logarithmic AGB of the plots (which was considered a surrogate of forest degradation) (adjusted R<sup>2</sup> = 0.69, *p* < 0.0001; Figure S3, Supplementary Materials) in line with Imai et al. [21]. Thus, nMDS axis-1 scores of plots were used as a forest "intactness index" in our analysis.

Forest intactness values (nMDS axis-1 scores) based on the stepwise selection were mainly explained by the short-wave infrared reflectance (bands 5 and 7), NDSI, EVI and textures based on the stepwise selection (Table 2). A comparison of observed vs. predicted nMDS axis-1 scores (i.e., intactness index) is shown in Figure 5; coefficients of correlation (R2) for the full model using all plots were 0.61 for 2009 and 0.64 for 2014. Cross-validation based on 1000 iterations indicated that 95% CIs of the mean coefficients of correlations were 0.19–0.90 for 2009 and 0.42–0.83 for 2014 (Figure 5).

**Figure 5.** Comparison of observed logarithmic vs. predicted logarithmic nMDS axis-1 values (forest intactness values) for 2009 (left diagram) and for 2014 (right diagram). Adjusted R<sup>2</sup> values of the full model using all plots were 0.61 for 2009 and 0.64 for 2014. 95% CIs of the mean coefficients of correlations were derived from a cross-validation procedure based on 1000 iterations.

Maps indicating the extrapolated forest intactness values (nMDS axis-1 values) over the entire area of the three FMUs are shown for 2009 and 2014 in Figure 6. Mean (95% CI) forest intactness values of Deramakot were 0.211 (0.130–0.306) for 2009 and 0.333 (0.271–0.405) for 2014, while those of Tangkulap were 0.062 (−0.018–0.142) for 2009 and 0.019 (−0.061–0.091) for 2014 (Figure 6). The mean iterated forest intactness value of Deramakot increased with a slight overlap in 95% CIs, while that of Tangkulap did not significantly increase and showed a broad overlap of CI (Figure 4).

**Figure 6.** Maps indicating the extrapolated forest intactness (nMDS axis-1 scores) over the entire area of the three FMUs for 2009 (**left**) and 2014 (**right**).
