Scaling relationship between tree respiration rates and biomass.
The WBE theory proposed by West, Brown and Enquist predicts that larger plant respiration rate, R, scales to the three-quarters power of body size, M. However, studies on the R versus M relationship for larger plants (i.e. trees larger than saplings) have not been reported. Published respiration rates of field-grown trees (saplings and larger trees) were examined to test this relationship. Our results showed that for larger trees, aboveground respiration rates RA scaled as the 0.82-power of aboveground biomass MA, and that total respiration rates RT scaled as the 0.85-power of total biomass MT, both of which significantly deviated from the three-quarters scaling law predicted by the WBE theory, and which agreed with 0.81-0.84-power scaling of biomass to respiration across the full range of measured tree sizes for an independent dataset reported by Reich et al. (Reich et al. 2006 Nature 439, 457-461). By contrast, R scaled nearly isometrically with M in saplings. We contend that the scaling exponent of plant metabolism is close to unity for saplings and decreases (but is significantly larger than three-quarters) as trees grow, implying that there is no universal metabolic scaling in plants.
Cheng
Dong-Liang
DL
Key Laboratory of Humid Subtropical Eco-geographical Process, Fujian Normal University, Ministry of Education, Fuzhou, Fujian Province 350007, Republic of China. chengdl02@yahoo.com.cn
Li
Tao
T
Zhong
Quan-Lin
QL
Wang
Gen-Xuan
GX
D018533:Biomass; D002245:Carbon Dioxide / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D014197:Trees / Q000502:physiology*
D002245:Carbon Dioxide; D009584:Nitrogen