Growth analysis on the C-D effect in self-thinning Masson pine (Pinus massoniana) stands

摘要

The competition-density (C-D) effect for self-thinning Masson pine stands was analyzed. The coefficients A(t) and B included in the reciprocal equation of the C-D effect in self-thinning stands (i.e. 1/w = A(t)rho + B, where w and rho, respectively represent mean stem volume and realized density) were calculated at each growth stage. The relationship between biological time tau, which is defined as the integral of the coefficient of growth in the general logistic equation with respect to physical time, and physical time t followed a hyperbolic curve. With increasing tau, the coefficient A(t) increased abruptly up to a maximum value, and then decreased gradually, whereas the coefficient B decreased exponentially. The relationship between realized density rho and initial density rho(i) followed the equation: 1/rho = 1/rho(i) + epsilon, where 1/epsilon means the asymptotic density at a given time. The coefficient epsilon increased exponentially with increasing tau. The density in the self-thinning stands tended to converge to the same density level after a sufficient lapse of time, irrespective of the difference in initial density. The coefficient of growth lambda(t) decreased with increasing stand age, whereas the final yield Y(t) tended to increase gradually with increasing stand age. (C) 2002 Elsevier Science B.V. All rights reserved. [References: 20]