Table 1.

Summary of mean leaf trait relationships (of the function Y = aX^b, fitted using equations of the form log y = a + b^*log X) for six diverse biomes (tropical rain forest, subtropical forest, cool temperate forest, cold temperate forest/prairie, desert, and alpine tundra/subalpine forest) represented in the field data set (all relationships P < 0.001)

Leaf Property, Y	Mean		r2 (mean)
	Trait, X	Scaling slope, b(±SE)
Net photosynthesis (mass-basis)	Leaf lifespan	−0.74  ±  0.05	0.88
Net photosynthesis (area-basis)*	Leaf lifespan	−0.29  ±  0.03	0.52
Dark respiration	Leaf lifespan	−0.58  ±  0.05	0.79
Leaf nitrogen concentration	Leaf lifespan	−0.32  ±  0.03	0.62
Specific leaf area	Leaf lifespan	−0.49  ±  0.04	0.79
Net photosynthesis (mass-basis)	SLA	1.31  ±  0.10	0.88
Dark respiration	SLA	1.02  ±  0.11	0.80
Leaf nitrogen concentration	SLA	0.61  ±  0.07	0.67
Leaf nitrogen content*	SLA	−0.42  ±  0.06	0.51
Net photosynthesis (mass-basis)	Leaf nitrogen concentration	1.73  ±  0.17	0.77
Dark respiration	Leaf nitrogen concentration	1.36  ±  0.11	0.71
Net photosynthesis (mass-basis)	Dark respiration	1.08  ±  0.09	0.79

Units, abbreviations, and mean minimum (±SE) and maximum (±SE) for leaf traits among biomes
		Mimimum ± SE	Maximum ± SE
Mass-based net photosynthesis (Amax)	nmol g−1s−1	21  ±  4	289  ±  64
Area-based net photosynthesis	μmol m−2s−1	3.7  ±  0.3	14.6  ±  1.2
Mass-based dark respiration	nmol g−1s−1	4.0  ±  0.3	35.2  ±  7.2
Leaf nitrogen concentration (leaf N)	mg/g	8.7  ±  0.6	40.9  ±  5.7
Leaf nitrogen content	g/m2	1.2  ±  0.2	4.4  ±  1.1
SLA	cm2/g	35  ±  6	267  ±  62
Leaf lifespan	months	2.5  ±  0.6	66.2  ±  10.6

Relationships only shown if significant at five or six sites. The slopes did not differ significantly among biomes. The mean (±1 SE) of the slopes and of the coefficient of determination (r²) are shown (N = 6). 

^*N = 5; data for site where relationship was not significant are not included.