Evaluation of Loblolly Pine Management Regimes in Mississippi for Biomass Supplies: A Simulation Approach

Alternative management regimes of loblolly pine (Pinus taeda) plantations were evaluated and compared for joint production of timber and biomass and exclusively for biomass production in Mississippi. The PTAEDA3.1 computerized yield simulator was used to predict growth effects of various site preparation techniques, initial planting densities, and thinning activities. Evaluation criteria included land expectation values (LEVs) and mean annual increment. Results indicated that sites with a site index of 50–70 (base age 25) yielded average annual stem residues of 0.86–1.20 tons/ac, from which 39.8–47.4 gallons of ethanol could be produced. Inclusion of pulpwood as a feedstock would approximately double biofuel production. Culminating sustainable annual outputs of total stem biomass exclusively for biofuel production using intensive site preparation was unprofitable on all sites because of high site preparation costs and low biomass prices. Sensitivity analyses indicated that LEVs and optimal management strategies were sensitive to changes in price of biomass relative to that of sawtimber. The rise of the relative biomass price would increase woody biomass availability for biofuels. It would also boost intensive management practices, such as intensive site preparation, closer initial tree spacings, earlier thinnings, and shorter rotation ages.