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Description

The temperate deciduous forests of eastern North America are subject to an array of ecosystem drivers including anthropogenic disturbance, gap dynamics, and both local and regional climate events. An ongoing “mesophication” trend has been observed in many of these forests where communities are shifting from oak dominance (Quercus spp.) to more mesophytic, shade-tolerant species (Acer spp.). Using a 30-year dataset (1979–2010) collected in an old-growth forest in southeastern Kentucky, we examined decadal patterns of distribution and relative abundance of dominant overstory taxa: oaks (Quercus spp.), maples (Acer spp.), hickories (Carya spp.), and beech (Fagus grandifolia). Overstory stem data were divided into three size classes, small (2.5–10 cm dbh), medium (10–25 cm dbh), and large (> 25 cm dbh), to assess regeneration patterns over time. Relative abundance and frequency of large oak and hickory stems were fairly consistent through time, but small and medium stem frequency and abundance decreased. On the contrary, small and medium sugar maple (A. saccharum) and beech were more frequent than large stems and generally increased in relative abundance over time. The observed spatial patterns suggested that oak species are persisting mainly as mature canopy trees with little recruitment in mesic areas of the study site, becoming more restricted to xeric ridgetop areas over time. Hickories did not exhibit a strong spatial pattern but showed an overall lack of recruitment in smaller size classes. Mesophytic species (maple, beech) appeared historically restricted to certain habitats (as evidenced by the clustered, limited distribution of mature trees) but are currently recruiting across a broader area of the watershed. This widespread “mesophication” trend in eastern deciduous forests is predicted to have important ecological and economic impacts, and understanding these changes in the context of multiple ecosystem drivers (fire, climate, human activity) is key for effective conservation and management.

Publication Date

4-9-2015

Project Designation

Graduate Research

Primary Advisor

Ryan W McEwan

Primary Advisor's Department

Biology

Keywords

Stander Symposium poster

Disciplines

Arts and Humanities | Business | Education | Engineering | Life Sciences | Medicine and Health Sciences | Physical Sciences and Mathematics | Social and Behavioral Sciences

Changes in Relative Abundance and Spatial Distribution of Dominant Overstory Taxa in an Old-growth Forest Over 30 Years

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