Southern Pine Plant Species Diversity Along a Disturbrance Gradient

Craig W. Hedman (Presenter), International Paper

Longleaf pine ecosystems comprise a diverse community of native groundcover species.  Critics of plantation forestry characterize loblolly and slash pine plantations as monocultures devoid of native groundcover and important ecosystem functions inherent to longleaf pine ecosystems. Vegetation and environmental data were collected in 49 plots at International Paper’s Southlands Experiment Forest in southwest Georgia. Species richness and abundance varied across all three pine cover types. While  significant differences in species richness and stand structure were detected, the magnitude of these differences were unclear.  Ordination and classification revealed that certain plots had a strong affinity for each other. When herbaceous composition (richness and identity) and abundance were analyzed simultaneously, all three pine cover types were represented in a point-cloud of 34 plots ranging between 1-100 yr. These plots were referred to as "benchmarks", i.e., typical of old-growth, longleaf pine-wiregrass communities.  Twenty-two (22) of the benchmark plots were in cutover plantations representing all three pine cover types.  All "non-benchmark plots" (15) were in plantations; eight were afforested oldfields.  The arrangement of herbaceous plots was greatly influenced by history of agriculture and burning frequency. This retrospective study identified the importance of land-use history when interpreting vegetation patterns in southern pine ecosystems. The presence and abundance of benchmark grasses and forbs in cutover plantations raise questions about the native vegetation’s resistance to disturbance and ecosystem resiliency.  Results suggest that plantations under varying degrees of management may look and potentially function like benchmark longleaf pine stands regardless of overstory species. 

Workshop IV: Terrestrial Ecosystems

Sustaining
Southern
Forests

a conference sponsored by the Southern Forest Resource Assessment