Effects of cultural intensity and planting density on stand-level aboveground biomass production and allocation for 12-year-old loblolly pine plantations in the Upper Coastal Plain and Piedmont of the southeastern United States

To strengthen financial returns and sustainably manage pine plantations for a mixture of traditional merchantable forest products and biomass for energy, we may need to modify and optimize loblolly pine ( Pinus taeda L.) plantation management regimes. There is limited information on stand-level biomass production and partitioning, which is critical to evaluate alternative culture regimes including cultural intensity and planting density. In the present study, effects of cultural intensity and planting density on biomass accumulation and partitioning in loblolly pine plantations at age 12 were evaluated with destructive biomass sampling data from plots of a unique culture/density study. More intensive culture increased stand-level stem, bark, and branch biomass and aboveground biomass but did not affect foliage biomass. In general, culture intensity did not affect stand-level aboveground biomass partitioning. Planting density significantly affected stand-level aboveground biomass accumulation and partitioning; however, this effect was no longer significant among densities above 2224 trees·ha –1 . More intensive culture or lower planting density resulted in less foliage per unit of live-branch biomass. Partitioning to stems relative to branches increased with increasing planting density. Both cultural intensity and planting density had no significant effects on leaf area index and stand-level specific gravity. Planting density significantly affected the foliage density. There were no significant interactions of planting density and cultural intensity.