Some Recent Japanese Theories of Yield-Density Relationships and their Application to Monterey Pine Plantations

Abstract Stand growth is viewed in terms of a simple biological model which will allow the forester to relate density and yield at any stage of stand development. Empirically determined size-density relationships of forest stands, and theoretical derivations of these relationships, have been developed by Japanese scientists and are reviewed here. These include the 3/2 power law for self-thinning to identify the maximum average tree size density relationship of a species; the reciprocal yield law for defining yield as a function of density at any stage of stand development; and the relationship between stand height and the reciprocal yield coefficients. The regions of random and competition related mortality are identified and separated. An application of these density dependent yield functions is given for Pinus radiata D. Don plantations. FOREST SCI. 23:517-534.