Scope of study. Tree biomass equations were fitted for shortleaf pine in southeast Oklahoma. Biomass equations developed by nonlinear regression techniques were used to estimate the tree and tree components biomass in unthinned control and thinned stands having three levels of thinning intensity. Biomasses in different thinning treatments were then compared using ANOVA techniques to investigate the response of aboveground biomass partitioning to thinning.

Finding and conclusions. Biomass partitioning was affected by thinning mainly to braches and bark. Unless heavily thinned, thinning treatment did not significantly affect the biomass allocation to bole. Biomass partitioning to branches was found to be higher with the increase of thinning intensity. Although the thinning seemed to reduce the total foliage biomass, it was evident that heavily thinned stands increase their portioning of biomass to foliage. Thinned stands partitioned smaller proportions of total biomass to bark.