In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 109, No. 22 ( 2012-05-29), p. 8600-8605
Abstract:
There is general agreement that competition for resources results in a tradeoff between plant mass, M , and density, but the mathematical form of the resulting thinning relationship and the mechanisms that generate it are debated. Here, we evaluate two complementary models, one based on the space-filling properties of canopy geometry and the other on the metabolic basis of resource use. For densely packed stands, both models predict that density scales as M −3/4 , energy use as M 0 , and total biomass as M 1/4 . Compilation and analysis of data from 183 populations of herbaceous crop species, 473 stands of managed tree plantations, and 13 populations of bamboo gave four major results: ( i ) At low initial planting densities, crops grew at similar rates, did not come into contact, and attained similar mature sizes; ( ii ) at higher initial densities, crops grew until neighboring plants came into contact, growth ceased as a result of competition for limited resources, and a tradeoff between density and size resulted in critical density scaling as M −0.78 , total resource use as M −0.02 , and total biomass as M 0.22 ; ( iii ) these scaling exponents are very close to the predicted values of M −3/4 , M 0 , and M 1/4 , respectively, and significantly different from the exponents suggested by some earlier studies; and ( iv ) our data extend previously documented scaling relationships for trees in natural forests to small herbaceous annual crops. These results provide a quantitative, predictive framework with important implications for the basic and applied plant sciences.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.1205663109
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
2012
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
Permalink
