Table 2. Equations and r2 and P values for leaf N, P, and N/P ratio relationships with mean annual temperature and absolute value of latitude
|
Figure |
Equation |
r 2 |
P value |
|
1 |
All Species |
||
|
N vs. MAT, bins |
log y = 1.25891 + 0.00863x – 0.00046x2 |
0.75 |
0.008 |
|
N vs. MAT, all data |
log y = 1.27373 + 0.00595x – 0.00036x2 |
0.05 |
<0.0001 |
|
P vs. MAT, bins |
log y = 0.35097 + 0.01518x – 0.00366x2 + 0.00009x3 |
0.95 |
0.0002 |
|
P vs. MAT, all data |
log y = 0.37413 – 0.00901x – 0.0005x2 |
0.39 |
<0.0001 |
|
N/P vs. MAT, bins |
log y = 0.900 + 0.014x |
0.85 |
0.0001 |
|
N/P vs. MAT, all data |
log y = 0.88442 + 0.01547x |
0.31 |
<0.0001 |
|
N vs. AL, bins |
log y = 1.06944 + 0.00978x – 0.00011x2 |
0.69 |
0.02 |
|
N vs. AL, all data |
log y = 1.17942 + 0.00231x |
0.04 |
<0.0001 |
|
P vs. AL, bins |
log y = –0.4506 + 0.07227x – 0.0051x2 + 0.00014x3 – 0.000118x4 |
0.98 |
0.001 |
|
P vs. AL, all data |
log y = –0.3246 + 0.0122x |
0.34 |
<0.0001 |
|
N/P vs. AL, bins |
log y = 1.30985 – 0.00377x – 0.00006x2 |
0.78 |
0.005 |
|
N/P vs. AL, all data |
log y = 1.37432 – 0.00769x |
0.24 |
<0.0001 |
|
2 |
Data by groups |
||
|
N vs. MAT |
|||
|
Grasses |
log y = 1.3374 – 0.000004x – 0.00056x2 |
0.10 |
0.0035 |
|
Herbs |
log y = 1.22296 + 0.02809x – 0.00126x2 |
0.08 |
<0.0001 |
|
Shrubs |
log y = 1.24046 + 0.00445x – 0.00041x2 |
0.07 |
0.0005 |
|
Trees |
log y = 1.33628 + 0.00007x – 0.00017x2 |
0.05 |
<0.0001 |
|
Conifers |
log y = 1.12038 – 0.00431x |
0.10 |
0.009 |
|
P vs. MAT |
|||
|
Grasses |
log y = 0.34277 – 0.00296x – 0.00114x2 |
0.31 |
<0.0001 |
|
Herbs |
log y = 0.43293 + 0.00442x – 0.00108x2 |
0.35 |
<0.0001 |
|
Shrubs |
log y = 0.29516 + 0.00107x – 0.00128x2 |
0.48 |
<0.0001 |
|
Trees |
log y = 0.3604 – 0.02022x |
0.25 |
<0.0001 |
|
Conifers |
log y = 0.23425 – 0.01433x |
0.49 |
<0.0001 |
|
N/P vs. MAT |
|||
|
Grasses |
log y = 0.95566 + 0.01014x |
0.11 |
0.001 |
|
Herbs |
log y = 0.79681 + 0.0172x |
0.24 |
<0.0001 |
|
Shrubs |
log y = 0.91688 + 0.01623x |
0.25 |
<0.0001 |
|
Trees |
log y = 1.00264 + 0.01182x |
0.20 |
<0.0001 |
|
Conifers |
log y = 0.88186 + 0.01074x |
0.36 |
<0.0001 |
|
3 |
Data by groups |
||
|
N vs. P |
|||
|
Conifers |
log y = 1.0398244 + 0.3666713x |
0.31 |
<0.0001 |
|
Grasses |
log y = 1.1462143 + 0.5112318x |
0.46 |
<0.0001 |
|
Herbs |
log y = 1.1443574 + 0.4652923x |
0.38 |
<0.0001 |
|
Shrubs |
log y = 1.1519265 + 0.2975617x |
0.40 |
<0.0001 |
|
Trees |
log y = 1.2213062 + 0.4507624x |
0.58 |
<0.0001 |
|
4 |
Data by genera |
||
|
N vs. MAT |
|||
|
Acer |
log y = 1.31446 – 0.00477x |
0.06 |
0.05 |
|
Betula |
log y = 1.32638 + 0.00679x |
0.16 |
0.0001 |
|
Callamagrostis |
log y = 1.42684 – 0.01975x |
0.10 |
0.07 |
|
Larix |
log y = 1.24569 + 0.00358x |
0.07 |
0.005 |
|
Vaccinium |
log y = 1.13874 + 0.01599x – 0.00072x2 |
0.23 |
0.002 |
|
P vs. MAT |
|||
|
Acer |
log y = 0.74249 – 0.09942x + 0.00424x2 |
0.39 |
<0.0001 |
|
Betula |
log y = 0.34704 – 0.00224x – 0.00069x2 |
0.04 |
0.09 |
|
Callamagrostis |
log y = 1.07264 – 0.11074x |
0.69 |
<0.0001 |
|
Larix |
log y = 0.34461 – 0.01145x |
0.22 |
<0.0001 |
|
Vaccinium |
log y = 0.26565 + 0.00878x – 0.00104x2 |
0.44 |
<0.0001 |
|
N/P vs. MAT |
|||
|
Acer |
log y = 0.37788 + 0.13769x – 0.00628 x2 |
0.54 |
<0.0001 |
|
Betula |
log y = 0.99091 + 0.01312x |
0.21 |
<0.0001 |
|
Callamagrostis |
log y = 0.3542 + 0.09099x |
0.57 |
<0.0001 |
|
Larix |
log y = 0.89695 + 0.01687x |
0.34 |
<0.0001 |
|
Vaccinium |
log y = 0.86192 + 0.01447x |
0.42 |
<0.0001 |
|
5, bins |
Data by groups |
||
|
N vs. MAT |
|||
|
Grasses |
log y = 1.37501 – 0.00036x+72 |
0.69 |
0.006 |
|
Herbs |
log y = 1.395 – 0.0002269 x + 72 |
0.47 |
0.03 |
|
Shrubs |
log y = 1.221 +0.006155x – 0.0004992x2 |
0.57 |
0.05 |
|
Trees |
log y = 1.315 + 0.004906x – 0.0003456x2 |
0.96 |
<0.0001 |
|
Conifers |
log y = 1.332 – 0.0001156 x + 72 |
0.72 |
0.002 |
|
P vs. MAT |
|||
|
Grasses |
log y = 0.40211 – 0.00075 x + 72 |
0.81 |
0.001 |
|
Herbs |
log y = 0.530 – 0.0005443 x + 72 |
0.76 |
0.002 |
|
Shrubs |
log y = 0.282 + 0.005518x – 0.001418x2 |
0.89 |
0.0004 |
|
Trees |
log y = 0.332 – 0.000447x + 72 |
0.76 |
0.0009 |
|
Conifers |
log y = 0.232 – 0.0003544 x + 72 |
0.86 |
<0.0001 |
|
N/P vs. MAT |
|||
|
Grasses |
log y = 0.9133 + 0.00039x+72 |
0.68 |
0.006 |
|
Herbs |
log y = 0.803 + 0.014x |
0.83 |
0.0006 |
|
Shrubs |
log y = 0.902 + 0.016x |
0.67 |
0.004 |
|
Trees |
log y = 0.979 + 0.012x |
0.69 |
0.003 |
|
Conifers |
log y = 0.89272 + 0.0103x |
0.78 |
0.0007 |
|
6, bins |
Data by genera |
||
|
N vs. MAT |
|||
|
Acer |
log y = 1.346 – 0.00786x |
0.67 |
0.004 |
|
Betula |
log y = 1.335 + 0.00538x |
0.56 |
0.008 |
|
Calluna |
log y = 1.039 + 0.063x – 0.00465x2 |
0.88 |
0.12 |
|
Pinus |
log y = 1.082 + 0.00704x2 – 0.00047x2 |
0.25 |
0.04 |
|
Vaccinium |
log y = 1.148 + 0.012x – 0.00065x2 |
0.44 |
0.03 |
|
P vs. MAT |
|||
|
Acer |
log y = 0.896 – 0.122x + 0.00504x2 |
0.75 |
0.015 |
|
Betula |
log y = 0.351 – 0.00322x – 0.000828x2 |
0.53 |
0.05 |
|
Calluna |
log y = 0.407 + 0.00557x – 0.00372x2 |
0.93 |
0.065 |
|
Pinus |
log y = 0.199 – 0.00809x |
0.36 |
0.002 |
|
Vaccinium |
log y = 0.00190 x2 – 0.000715x + 0.194 |
0.45 |
0.05 |
|
N/P vs. MAT |
|||
|
Acer |
log y = 0.346 + 0.138x – 0.00615x2 |
0.83 |
0.005 |
|
Betula |
log y = 1.018 + 0.010x |
0.65 |
0.003 |
|
Calluna |
log y = 0.684 + 0.041x |
0.97 |
0.003 |
|
Pinus |
log y = 0.885 + 0.00839x |
0.22 |
0.02 |
|
Vaccinium |
log y = 0.916 + 0.014x |
0.44 |
0.01 |
In several cases where power functions were the best fit, mean annual temperature MAT was adjusted to all positive values by adding 7° C to avoid automatically causing negative and positive MAT to have the same value for the fitted dependent variable. r2, coefficient of determination; AL, absolute value of latitude.