Applying the Gompertz growth equation,the auther derived the formual for height-number curve in even-aged forest stands. The mathematical expression of the height-number curve is
N = d - aexp [ - bexp (cH)]
where N is a tree number,H is a stand height and a, b, c, d, are constants.
The applicability of this equation was examined by applied it to the observed height-number relationships. The goodness of fit of the equation was good enough for use in comparison with following existing height-number equaiton,
when H < H_0, N = α exp (-βH)
when H ≧ H_0, N = γ exp (-δH)
where N is a tree number, H is a stand height and H_0, α,β,γ,δ are constants.