Spatial pattern and driving factors of biomass carbon density for natural and planted coniferous forests in mountainous terrain, eastern Loess Plateau of China

Forest Ecosystems

Table 2 Multi-group comparison of path coefficients between natural and planted coniferous forests. A non-significant value, highlighted in bold, indicates that the path contribution to the model is equal between forest types

Free parameter between-groups was constrained	MLχ²	ΔMLχ²	P-value
None	9.688
path from LAT to PRCP	18.075	8.434	0.004
path from LAT to ELE	45.411	35.723	0.000
path from COV to BCD	9.726	0.038	0.846
path from PRCP to BCD	10.115	0.427	0.514
path from ELE to BCD	13.816	4.127	0.042
path from LAT to AGE	16.807	7.101	0.008
path from ELE to AGE	9.844	0.153	0.696
path from AGE to COV	14.844	5.233	0.022
path from AGE to BCD	9.854	0.166	0.684
path from PRCP to COV	9.707	0.024	0.876

The first row shows the maximum likelihood χ² estimates (MLχ²) when all parameters are free. The remaining rows show the result by constraining one parameter at a time. The difference between the fully free model and the rest is given as ΔMLχ², and the P-value indicates the probability that the constraint of that parameter changes the model. Bonferroni-corrected P-value threshold, 0.05/13 = 0.0038. BCD, biomass carbon density; AGE, stand age; COV, stand coverage; LAT, latitude; ELE, elevation; PRCP, mean annual precipitation