A Simulation Study of Forest Dynamics Under Multiple Harvest Regimes and Wind Disturbances in Southern Mississippi

Forests of the coastal plain region of the southern United States are unique in their productivity, biodiversity, and economic value. However, natural and anthropogenic disturbances may trigger forest age structure and spatial distribution variation. Detecting and predicting tree species distribution patterns can help to understand the dynamics of disturbances in order to develop adequate forest management plans. In this study, we first integrated the spatially explicit forest landscape model, LANDIS 6.0, with Mississippi Institute for Forest Inventory (MIFI) data and simulated coastal forest dynamics under natural succession, forest harvesting management regimes (20-year and 40-year logging re-entry intervals), and wind disturbance for 100 years. Then, we analyzed loblolly pine (Pinus taeda) productivity, age structure and spatial distribution. After 40 years, most loblolly pines grow into a sawtimber product class. From potential productivity structure analysis, the productivity seems steadier in 20-year logging regime when compared to a short time seedling gap in the 40 year logging intervals. Spatial pattern characteristic analysis was performed using Fragstats 3.3 software to calculate number of patches (NP) and landscape shape index (LSI) for projected maps. The results suggest that wind has larger capacity to fragment habitats than harvests. Furthermore, t-test results show that there is a significant difference between natural succession and harvest regimes in productivity and landscape pattern indicators, while only the difference in landscape patterns is evident between with and without wind disturbance scenarios. This suggests that harvest influences are more obvious than wind disturbance. Thus, with the constantly changing forest landscape associated with human and natural disturbances, human elements should have more considerations in forest management planning.