A meta-analysis of changes in soil organic carbon stocks after afforestation with deciduous broadleaved, sempervirent broadleaved, and conifer tree species

Table 4 Stepwise regression to detect factors (T, P, A and I) determining SOC stock changes following afforestation

Plant classification	Soil depth	Equation	R²	Sig. (P)	N
Total	0–20	∆Cs = 0.274A − 0.181I + 3.876	0.235	0.000**	261
	20–40	∆Cs = − 0.305I + 8.002	0.161	0.000**	168
	40–60	∆Cs = − 0.115I + 3.632	0.038	0.038*	115
Deciduous broadleaved	0–20	∆Cs = 0.297A − 0.56	0.237	0.001**	101
	20–40	∆Cs = − 2.455 T + 0.039P + 3.313	0.294	0.000**	48
	40–60	∆Cs = 0.015P − 4.876	0.199	0.005**	38
Sempervirent broadleaved	0–20	∆Cs = 0.85A − 5.829	0.392	0.000**	62
	20–40	∆Cs = 0.672A − 0.271I + 1.494	0.318	0.000**	48
	40–60	∆Cs = 0.538A − 3.83	0.37	0.000**	37
Sempervirent conifer	0–20	∆Cs = 0.204A − 0.253I + 7.786	0.37	0.000**	98
	20–40	∆Cs = − 0.471I + 11.23	0.336	0.000**	72
	40–60	∆Cs = − 0.156I + 4.061	0.109	0.038*	40

∆Cs is SOC stock change following afforestation; T (°C) is the mean annual temperature; P (mm) is the mean annual precipitation; A (year) is the plantation age; I (Mg ha⁻¹) is the initial SOC stock
* and ** indicate significant difference at the 0.05 level (P < 0.05) and 0.01 level (P < 0.01), respectively

ISSN: 1297-966X