Understory plant biomass dynamics of prescribed burned Pinus palustris stands

• Longleaf pine forest management is characterized by frequent prescribed fire.
• Models for prediction of ground cover biomass, and hence fuel load, are scarce.
• The new models estimate the dynamics of herbaceous and woody ground cover biomass.
• The equations incorporate the effect of stand age, basal area and fire frequency.
• The set of equations can be integrated into fire management and carbon balance models.

Longleaf pine (Pinus palustris Mill.) forests are characterized by unusually high understory plant species diversity, but models describing understory ground cover biomass, and hence fuel load dynamics, are scarce for this fire-dependent ecosystem. Only coarse scale estimates, being restricted on accuracy and geographical extrapolation, are available. We analyzed the dynamics of ground cover biomass under different prescribed burning regimes in longleaf pine stands in the southeastern United States. We developed a set of functions to simulate ground cover biomass dynamics in stands of varying age, basal area and fire management history. The subsequent models allow for estimation of ground cover biomass for unburned stands and living woody and herbaceous ground cover biomass for burned stands. Woody ground cover was highly reduced as fire frequency increased, and also affected by stand basal area when time since last burning was longer than two years. Herbaceous ground cover was affected little by burning frequency but was reduced as basal area increased. This novel model system is a useful tool that can be incorporated into fire management and carbon balance models.