Assessment of forest carbon storage dynamics requires a variety of techniques including simulation models.
We developed a hybrid model to assess the effects of silvicultural management systems on carbon (C)
budgets in longleaf pine (Pinus palustris Mill.) plantations in the southeastern U.S. To simulate in situ C
pools, the model integrates a growth and yield model with species-specific allometric and biometric
equations and explicitly accounts for the impacts of both thinning and prescribed fire. To estimate the
ex situ C pool, the model used the outputs of merchantable products from the growth and yield model
with current values of forest product conversion efficiencies and forest product decay rates. The model
also accounts for C emissions due to transportation and silvicultural activities. Site productivity (site
quality) was the major factor controlling stand C density followed by rotation length. Thinning reduced
C sequestration, as the slow growth rate of longleaf pine reduced the potential of C sequestration in forest
products. Prescribed burning reduced average C stock by about 16–19%, with the majority of the reduction
in the forest floor. In a comparison of longleaf pine C dynamics with slash pine (Pinus elliottii
Engelm.), both species reached a similar average C stock at age 75 years, but when averaged across the
whole rotation, slash pine sequestered more C. Nevertheless, for medium quality sites, C sequestration