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Table 3 Correlation coefficient between soil organic carbon (SOC) and mean annual precipitation (MAP), mean annual temperature (MAT), sand, silt, clay, age, altitude, and pH for all tree species and the four categories of tree stands

From: Influence of trees and associated variables on soil organic carbon: a review

 

All tree species

Coniferous

Deciduous

Evergreen

Mixed

R2 (%)

r

R2(%)

r

R2 (%)

r

R2 (%)

r

R2 (%)

r

MAP

0.9

0.09

13.0

0.36

3.3

− 0.18

48.6

0.69

0.1

0.03

MAT

13.6

− 0.37*

0.4

− 0.06

27.2

− 0.52*

1.7

− 0.13

21.4

− 0.45*

Sand

36.7

− 0.61*

40.8

− 0.63*

27.7

− 0.52*

88.0

− 0.93*

35.7

− 0.59*

Silt

33.6

0.58*

22.1

0.47

11.3

0.33

96.0

0.97*

52.6

0.72*

Clay

1.2

0.11

31.2

0.56*

2.4

0.15

37.0

0.60

4.8

− 0.21

Age

27.0

0.52*

3.3

0.18

23.5

0.48

1.6

0.13

2.6

− 0.16

Altitude

2.0

0.14

0.1

0.04

25.0

0.50*

100

1.0

14.0

0.37

pH

3.7

− 0.20

6.2

− 0.25

8.2

− 0.28

1.7

0.13

10.8

− 0.32

  1. *Significant at p < 0.05 (using t test)