Appendix A
Table A1.
General descriptions of subsoil τ (year) used in this study.
Table A1.
General descriptions of subsoil τ (year) used in this study.
Forest Types | df | Mean | Standard Deviation | Minimum | Maximum | Coefficient of Variance (%) |
---|
DBF | 154 | 82.9 | 68.7 | 10.1 | 411.0 | 82.9% |
DNF | 55 | 75.3 | 78.6 | 2.85 | 312.0 | 104% |
EBF | 148 | 59.9 | 40.7 | 4.59 | 221.0 | 68% |
ENF | 53 | 77.6 | 60.8 | 13.0 | 311.0 | 78.4% |
NBF | 220 | 71.3 | 80.9 | 2.32 | 896.2 | 113% |
Climate zones | | | | | | |
Boreal | 79 | 89.5 | 68.6 | 16.4 | 318.0 | 76.7% |
Subtropical | 285 | 60.1 | 41.0 | 2.32 | 253.0 | 68.2% |
Temperate | 192 | 92.2 | 96.8 | 9.25 | 896.2 | 105% |
Tropical | 74 | 49.7 | 45.6 | 4.59 | 221.0 | 91.8% |
Forest origin | | | | | | |
Natural | 337 | 78.2 | 73.2 | 2.32 | 896.2 | 93.6% |
Plantation | 293 | 65.6 | 62.6 | 2.85 | 481.0 | 95.3% |
Forest age (486 observations) | | | | | | |
Young | 233 | 67.5 | 60.3 | 2.32 | 411.0 | 89.4% |
Middle-aged | 152 | 71.1 | 57.7 | 12.2 | 315.0 | 81.1% |
Mature | 101 | 92.3 | 111 | 14.8 | 896.2 | 121% |
All | 630 | 72.4 | 68.6 | 2.32 | 896.2 | 94.8% |
Table A2.
Statistics of GLMM relating environmental variables with subsoil τ, treating the sites as a random effect.
Table A2.
Statistics of GLMM relating environmental variables with subsoil τ, treating the sites as a random effect.
Variable | Slope | 95% CI | R2 (m/c) |
---|
MAT | −0.014 *** | (−0.018, −0.010) | 0.09/0.10 |
Log (MAP) | −0.367 *** | (−0.469, −0.266) | 0.07/0.09 |
Log (RH) | −0.558 *** | (−0.684, −0.432) | 0.11/0.13 |
Log (GPP) | −0.370 *** | (−0.474, −0.265) | 0.07/0.43 |
Log (EVI) | −0.769 *** | (−1.048, −0.443) | 0.04/0.43 |
Log (NDVI) | −0.816 *** | (−1.130, −0.502) | 0.04/0.44 |
Log (Soil C:N) | 0.672 *** | (0.465, 0.665) | 0.44/0.56 |
Log (SMC) | 0.485 *** | (0.362, 0.609) | 0.09/0.34 |
Log (SMN) | 0.454 *** | (0.301, 0.607) | 0.05/0.32 |
Table A3.
Statistics of GLMM relating environmental variables with subsoil τ, treating the stand types by sites as a random effect.
Table A3.
Statistics of GLMM relating environmental variables with subsoil τ, treating the stand types by sites as a random effect.
Variable | Slope | 95% CI | R2 (m/c) |
---|
MAT | −0.016 *** | (−0.020, −0.012) | 0.10/0.23 |
Log (MAP) | −0.367 *** | (−0.469, −0.266) | 0.07/0.07 |
Log (RH) | −0.601 *** | (−0.739, −0.461) | 0.12/0.12 |
Log (GPP) | −0.370 *** | (−0.475, −0.266) | 0.07/0.07 |
Log (EVI) | −0.769 *** | (−1.076, −0.463) | 0.04/0.04 |
Log (NDVI) | −0.816 *** | (−1.130, −0.503) | 0.04/0.04 |
Log (Soil C:N) | 0.675 *** | (0.628, 0.732) | 0.44/0.69 |
Log (SMC) | 0.512 *** | (0.389, 0.635) | 0.10/0.12 |
Log (SMN) | 0.521 *** | (0.365, 0.676) | 0.06/0.06 |
Table A4.
Results of PCA of environmental variables.
Table A4.
Results of PCA of environmental variables.
Variable | Loading Factor |
---|
Climate | |
MAT (°C) | 0.96 |
Log (MAP) (mm) | 0.93 |
Log (RH) (%) | 0.99 |
Cumulative variance explained (%) | 92% |
Vegetation | |
Log (NDVI) | 0.97 |
Log (GPP) (g C m−2 year−1) | 0.90 |
Log (EVI) | 0.98 |
Cumulative variance explained (%) | 91% |
Soil variables | |
Log (SMC) (g C m−2) | 0.82 |
Log (C:N) | 0.50 |
Log (SMN) (g N m−2) | 0.79 |
Cumulative variance explained (%) | 63% |
Figure A1.
The variation of C turnover time (τ, naturally log-transformed) according to climatic, soil, and vegetation variables, etc., in the sample mean (
A–
I) are constant. The fitted lines were deter-mined by GLMM, with sites as the random factor. The parameters are shown in
Table A2.
Figure A1.
The variation of C turnover time (τ, naturally log-transformed) according to climatic, soil, and vegetation variables, etc., in the sample mean (
A–
I) are constant. The fitted lines were deter-mined by GLMM, with sites as the random factor. The parameters are shown in
Table A2.
Figure A2.
The variation of C turnover time (τ, naturally log-transformed) according to climatic, soil, and vegetation variables, etc., in the sample mean (
A–
I) are constant. The fitted lines were deter-mined by GLMM, with the stand types by sites as random factors. The parameters are shown in
Table A3.
Figure A2.
The variation of C turnover time (τ, naturally log-transformed) according to climatic, soil, and vegetation variables, etc., in the sample mean (
A–
I) are constant. The fitted lines were deter-mined by GLMM, with the stand types by sites as random factors. The parameters are shown in
Table A3.
Figure A3.
A conceptual model of the overall effects of environmental variables on τ. Climate variables include MAT, MAP, and RH. Vegetation variables include NDVI, GPP, and EVI. Soil variables include SMC, C:N, and SMN. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ.
Figure A3.
A conceptual model of the overall effects of environmental variables on τ. Climate variables include MAT, MAP, and RH. Vegetation variables include NDVI, GPP, and EVI. Soil variables include SMC, C:N, and SMN. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ.
Figure A4.
A conceptual model of the overall effects of environmental variables on different forest types τ. Climate variables include MAT, MAP, and RH. Vegetation variables include NDVI, GPP, and EVI. Soil variables include SMC, C:N, and SMN. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ.
Figure A4.
A conceptual model of the overall effects of environmental variables on different forest types τ. Climate variables include MAT, MAP, and RH. Vegetation variables include NDVI, GPP, and EVI. Soil variables include SMC, C:N, and SMN. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ.
Figure A5.
The main influencing factors of C turnover in the subsoil of the boreal zone were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: *** p < 0.001.
Figure A5.
The main influencing factors of C turnover in the subsoil of the boreal zone were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: *** p < 0.001.
Figure A6.
The main influencing factors of C turnover on the subsoil of the temperate zone were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: ** p < 0.01, *** p < 0.001.
Figure A6.
The main influencing factors of C turnover on the subsoil of the temperate zone were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: ** p < 0.01, *** p < 0.001.
Figure A7.
The main influencing factors of C turnover in the subsoil of the subtropical zone were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: * p < 0.05, *** p < 0.001.
Figure A7.
The main influencing factors of C turnover in the subsoil of the subtropical zone were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: * p < 0.05, *** p < 0.001.
Figure A8.
The main influencing factors of C turnover on the subsoil of the tropical zone were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: * p < 0.05, *** p < 0.001.
Figure A8.
The main influencing factors of C turnover on the subsoil of the tropical zone were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: * p < 0.05, *** p < 0.001.
Figure A9.
The main influencing factors of C turnover on the subsoil of DBF were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: *** p < 0.001.
Figure A9.
The main influencing factors of C turnover on the subsoil of DBF were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: *** p < 0.001.
Figure A10.
The main influencing factors of C turnover in the subsoil of DNF were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: *** p < 0.001.
Figure A10.
The main influencing factors of C turnover in the subsoil of DNF were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: *** p < 0.001.
Figure A11.
The main influencing factors of C turnover in the subsoil of ENF were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: *** p < 0.001.
Figure A11.
The main influencing factors of C turnover in the subsoil of ENF were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: *** p < 0.001.
Figure A12.
The main influencing factors of C turnover in the subsoil of EBF were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: ** p < 0.01, *** p < 0.001.
Figure A12.
The main influencing factors of C turnover in the subsoil of EBF were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: ** p < 0.01, *** p < 0.001.
Figure A13.
The main influencing factors of C turnover on the subsoil of NBF were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: *** p < 0.001.
Figure A13.
The main influencing factors of C turnover on the subsoil of NBF were obtained by the SEM model. The symbols “↑” and “↓” indicate a positive or negative correlation between environmental factors and subsoil τ. The goodness of fit statistics for the effect size model of the relationship are as follows: *** p < 0.001.
Figure A14.
Sensitivity of subsoil organic C turnover time (τ, year) to changes in MAT (°C) without the values obtained from the turning from linear regression.
Figure A14.
Sensitivity of subsoil organic C turnover time (τ, year) to changes in MAT (°C) without the values obtained from the turning from linear regression.
Figure A15.
Sensitivity of NPP (kg C m−2 year−1) of subsoil (0.2–1 m) to changes in MAT (°C) obtained from linear regression.
Figure A15.
Sensitivity of NPP (kg C m−2 year−1) of subsoil (0.2–1 m) to changes in MAT (°C) obtained from linear regression.