An Analysis and Models of Basal Area Growth in 45-Year-Old Unthinned and Thinned Slash Pine Plantation Plots

Abstract Net basal area yield equations and survival functions for unthinned slash pine plantations are developed from 45-year-old experimental plot data representing different planting densities in a spacing and thinning study. These equations are used in conjunction with data from thinned plots to define a measure of the degree to which trees in a thinned plantation had been affected by competition relative to the trees in an unthinned plantation of the same age and average number of trees per unit area. Data from thinned plots are used to illustrate how this measure can be used to improve the prediction of basal area growth in thinned plantations based on the expected growth and yield of unthinned plantations. Forest Sci. 30:933-942.