Variation in plant functional traits and vertical structure in harvested forest openings in the Southern Appalachians

WCU Author/Contributor (non-WCU co-authors, if there are any, appear on document)
Thomas Grover Green (Creator)
Institution
Western Carolina University (WCU )
Web Site: http://library.wcu.edu/
Advisor
Laura DeWald

Abstract: For over two decades, scientists and land managers in the eastern United States have had concerns about the loss of early seral habitat resulting from changes in land use and disturbance regimes. Forest harvest can create early seral habitat within the forested landscape. The size of early seral forest openings and the distance from forest edge can influence microclimate and biotic interactions which affect plant functional traits and vertical structure in openings. This study asks whether there are differences in plant functional traits and vertical structure among openings of different sizes and at different distances from the forest edge. Study sites consisted of eleven shelterwood-harvested openings in the Nantahala National Forest from 2.4 to 13.6 ha in size and five to nine years since harvest, with a range of center-to-edge distances of 29 to 155 m. Openings were grouped into small, medium, and large sizes based on center-to-edge distance, and each opening was divided into concentric zones based on distance from forest edge. Vertical vegetation structure was quantified with mean height of vegetation and foliage height diversity. The woody vegetation was sampled, and shade tolerance, seed mass and wood density values for the community were analyzed to look for differences among opening sizes and opening zones. Vegetation was denser closer to the ground in small openings than in medium and large openings, and no significant differences were found in foliage height diversity for either opening size or distance from edge. Seed mass was lower in small openings than in medium and large, and at opening centers than edges. Shade tolerance and tree wood density did not differ significantly among opening sizes or zones. Seed mass did display patterns based on opening size and distance from edge, but size and distance from edge were not strong predictors of community-level shade tolerance or tree wood density, or the vertical structure variables measured here. Results suggest that some patterns found may be due to differences in species distribution among study sites. Other factors such as pre-disturbance community and the influence of stump sprouts and leave trees may be affecting community-weighted functional trait means in these openings as well. These results suggest that land managers have a range of sizes to choose from when creating early seral openings and that smaller openings may achieve similar objectives to large openings.

Additional Information

Publication
Thesis
Language: English
Date: 2017
Keywords
early seral forest, functional traits, southern Appalachians, vertical structure, woody vegetation

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