Table 2 Models of foliar Δ13C using each of the three data sets.

From: Continental scale variability of foliar nitrogen and carbon isotopes in Populus balsamifera and their relationships with climate

 

Effect

SS1

Estimate ± SE2

P

Global data

Intercept

258

8.98 ± 0.89

<0.0001

logMAP3

685

4.28 ± 0.26

<0.0001

sqrt(Elevation)4

174

−0.05 ± 0.01

<0.0001

Global data with P. balsamifera

Intercept

1435

15.50 ± 0.67

<0.0001

logMAP

379

2.44 ± 0.20

<0.0001

sqrt(Elevation)

348

−0.06 ± 0.01

<0.0001

P. balsamifera data

Intercept

445

18.40 ± 1.20

<0.0001

logMAP

23.1

1.36 ± 0.39

<0.0001

sqrt(Elevation)

13.1

−0.02 ± 0.01

<0.0001

  1. 1Sum of squares. 2Standard error. 3Base 10 logarithm of Mean Annual Precipitation (mm). 4Square root of elevation (m).
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