Ecological Archives A021-146-A6

S. Luyssaert, D. Hessenmöller, N. von Lüpke, S. Kaiser, and E. D. Schulze. 2011. Quantifying land use and disturbance intensity in forestry, based on the self-thinning relationship. Ecological Applications 21:3271–3283.

Appendix F. Multiple-regression analysis of the observed diameters in relation to stand density, type of management, study region, canopy tree species, and soils. Tree mix refers to “conifer” or “broadleaved” stands. Soil: classification of soil types by the German Soil Classification System (Bodenkundliche Kartieranleitung KA5).

model 1 – with soil data (1,612 observations)


Variable

df

Sum of squares

Mean square

F value

P (>F)

Sum of Squares (%)


log(Stand density)

1

213.9

212.9

2619

< 0.01

59.3

Management

3

5.1

1.7

21

< 0.01

1.4

Region

2

7.5

3.7

46

< 0.01

2.1

Tree mix

1

2.3

2.3

28

< 0.01

0.7

Soil

20

2.7

0.1

1

0.036

0.7

Residuals

1584

128.7

0.1

 

 

35.8


 

 

 

 

 

 

 

 

model 2 - without soil data (4,602 observations)

Variable

df

Sum of squares

Mean square

F value

P (>F)

Sum of Squares (%)


log(Stand density)

1

586.9

586.9

9964

< 0.01

66.8

Management

6

10.9

1.8

30

< 0.01

1.2

Region

2

7.7

3.8

65

< 0.01

0.9

Tree mix

1

2.4

2.4

40

< 0.01

0.3

Residuals

4.591

270.4

0.1

 

 

30.8


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