Vegetation response to midstorey mulching and prescribed burning for wildfire hazard reduction and longleaf pine (Pinus palustris Mill.) ecosystem restoration


Dense midstorey vegetation, developed during fi re exclusion, not only reduces understorey plant
diversity and increases the risk of damaging wildfi re but also impedes efforts to safely restore
prescribed burning in longleaf pine (
effects of midstorey reduction on stand structure and plant diversity in a forest treated by mulching
alone 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 from
32.4 to 16.9 per cent, rapid regrowth of hardwoods led to recovery by end of the second growing
season. This, along with gains by shrubs, vines, grasses and forbs, resulted in a near doubling of
understorey plant cover. Although tree seedling increases were not related to fi re season, peak
responses occurred for shrubs and vines after winter fi re and spring fi re, grasses following winter
fi re and forbs after summer fi re. An increase in species richness (18.7 – 24.5) and decline in species
evenness (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 distributed
as a result of differential rates of plant growth. While mulching led to a short-term increase in
woody and herbaceous understorey plants, prescribed fi re is needed to curtail redevelopment of the
woody midstorey and further increase grasses and forbs.

  • Citation: Brockway, Dale G., Outcalt, Kenneth W., Estes, Becky L., Rummer, Robert B. 2009. Vegetation response to midstorey mulching and prescribed burning for wildfire hazard reduction and longleaf pine (Pinus palustris Mill.) ecosystem restoration. Forestry 82(3):299-314
  • Posted Date: October 16, 2009
  • Modified Date: June 19, 2012
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