Enquist and Niklas propose that trees in natural forests have invariant size-density distributions (SDDs) that scale as a -2 power of stem diameter, although early studies described such distributions using negative exponential functions. Using New Zealand and ‘global’ data sets, we demonstrate that neither type of function accurately describes the SDD over the entire diameter range.
Coomes, D.A.; Duncan, R.P.; Allen, R.B.; Truscott, J.