Using a system mixed-effects modeling method to estimate tree compartment biomass for intensively managed loblolly pines—an allometric approach

Allometric relationships between total and individual tree compartment (stem, root, branch, and foliage) biomass were investigated for intensively managed loblolly pine (Pinus taeda L.) plantations in the Lower Coastal Plain and Piedmont of Georgia. It was found that the percent of stem biomass increases with age while the inverse relationship was found for foliage and branches. Cultural treatments also impacted the proportional allocation among various tree compartments. Specifically, this investigation showed that compared with unfertilized trees, annually fertilized trees in the Lower Coastal Plain had a larger proportional biomass allocation to the stem relative to root, branch, and foliage compartments. A system of related compartment biomass models was developed that reproduces observed relationships in the raw data. This system of models uses total tree biomass to obtain estimates of biomass for other tree compartments. The flexibility of the system of biomass prediction models allows users to estimate biomass for the various compartments as a function of another known compartment biomass.