Table 1 Models of foliar δ¹⁵N using each of the three data sets.

Global data; R² = 0.46

Intercept

3721

5.38 ± 0.27

<0.0001

logMAP³

10561

−3.26 ± 0.10

<0.0001

MAT⁴

65767

0.24 ± 0.003

<0.0001

Log[N]⁵

24933

7.67 ± 0.15

<0.0001

Global data with P. balsamifera; R² = 0.46

Intercept

3885

5.45 ± 0.27

<0.0001

logMAP

11103

−3.30 ± 0.10

<0.0001

MAT

70335

0.25 ± 0.003

<0.0001

Log[N]

25031

7.61 ± 0.15

<0.0001

P. balsamifera data; R² = 0.05

Intercept

16.1

−3.51 ± 2.69

0.1916

logMAP

2.39

0.49 ± 0.97

0.6148

MAT

115

−0.21 ± 0.06

0.0005

Log[N]

185

5.17 ± 1.17

<0.0001