Date of Award

5-2018

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Forestry and Environmental Conservation

Committee Member

Dr. Donald Hagan, Committee Chair

Committee Member

Dr. Thomas Waldrop

Committee Member

Dr. Kyle Barrett

Abstract

Decades of fire exclusion in the Southern Appalachian region have caused the forests to convert from open woodlands to closed canopy mesic forests with sparse understories. The main objectives of this study were 1) to assess the effects of four fuel reduction methods (burned [B], mechanical fuel treatment [M], mechanical treatment + burned [MB], and control [C]) on understory vegetative functional groups from 2001-2016; and 2) to investigate understory community-level responses after 15 years of treatment effects. In response to the first objective, oak species had significant increases in MB and B, relative to other treatments. However, mesic hardwood species had comparably significant increases in B, driven by red maple. Similarly, shrub species had significant increases in M, driven by mountain laurel and great rhododendron. Conversely, forb and graminoid species had non-significant increases in cover among all treatments. In response to the second objective, vegetation patterns seemed to overlap with respect to treatment type, suggesting little separation in understory community. However, some clusters from the hierarchical cluster analysis showed divergent communities from C treatments, particularly for shrubs and herbaceous species. In response to the third objective, select herbaceous species indicate changes in understory abiotic conditions, suggesting reversal from mesic conditions. Additionally, these findings suggest the M may not serve as a surrogate for B treatments over 15 years. MB treatments, however, are providing sufficient abiotic conditions conducive to understory oak, pine, and herbaceous species regeneration. Overall, these fire and fire surrogates (FFS) (B, M, MB and C) suggest a slow response in understory vegetation.

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