Vegetation response to midstorey mulching and prescribed burning for wildfire hazard reduction and longleaf pine (Pinus palustris Mill.) ecosystem restoration
| Authors: | Dale Brockway, Kenneth Outcalt, Becky Estes, Robert Rummer |
| Year: | 2009 |
| Type: | Scientific Journal |
| Station: | Southern Research Station |
| DOI: | https://doi.org/10.1093/forestry/cpp010 |
| Source: | Forestry 82(3):299-314 |
Abstract
Dense midstorey vegetation, developed during fi re exclusion, not only reduces understorey plantdiversity and increases the risk of damaging wildfi re but also impedes efforts to safely restoreprescribed burning in longleaf pine ( effects of midstorey reduction on stand structure and plant diversity in a forest treated by mulchingalone and also when followed by prescribed fi re during the winter, spring or summer. For trees cm diameter at breast height (d.b.h.), mulching reduced stand density (1220 – 258 trees ha basal area (24 – 17.7 m in loblolly pine ( L.). Removing hardwoods and smaller pines resulted in a decline in tree species richness (8.9 – 4.4).Despite a modest increase in evenness (0.72 – 0.79), tree species diversity ( were largely driven by changes in richness. While the cover of tree seedlings initially declined from32.4 to 16.9 per cent, rapid regrowth of hardwoods led to recovery by end of the second growingseason. This, along with gains by shrubs, vines, grasses and forbs, resulted in a near doubling ofunderstorey plant cover. Although tree seedling increases were not related to fi re season, peakresponses occurred for shrubs and vines after winter fi re and spring fi re, grasses following winterfi re and forbs after summer fi re. An increase in species richness (18.7 – 24.5) and decline in speciesevenness (0.86 – 0.70) produced only a small increase in understorey species diversity ( 2.45). The greater number of understorey species following treatment were less equitably distributedas a result of differential rates of plant growth. While mulching led to a short-term increase inwoody and herbaceous understorey plants, prescribed fi re is needed to curtail redevelopment of thewoody midstorey and further increase grasses and forbs.