Transitions from Oak to Maple Dominated Forests in the eastern U.S

1. Transitions from Oak to Maple Dominated Forests in the eastern U.S Zack Stewart¹, Kristen de Graauw¹, Sandy Cain¹, Andy Worthington² ¹Dept. of Geography and Anthropology, Kennesaw State University ²Dept. of Geography, Indiana State University Abstract Fire suppression, deer browsing, and clearcutting restrict oak (Quercus spp.) regeneration with the first limitation having the largest impact. Not only does it prevent oak regrowth but fire suppression also enables red maple (Acer rubrum) populations to flourish. Five permanent 10 by 10 meter plots were established in West Virginia’s Fernow Experimental Forest to identify the species present, record DBH measurements, and plot stem coordinates. Based on the data collected in the field, size distribution and frequency per plot was graphed and used to create bubble charts. Analysis of the charts showed a large amount of small DBH red maples and very few large DBH oaks. These results suggest trends of oak to maple succession as observed in other forests in the eastern United States. Methods Five permanent 10 meter by 10 meter plots were established in a section of the Fernow Experimental Forest outside of Morgantown, West Virginia. GPS readings were taken at 0,0 and all stems were identified by species and given x,y coordinates. Circumference was measured at breast height (1.3 m) and was entered into an Excel spreadsheet to calculate DBH (diameter at breast height). Once the field data was collected, the number of stems per species was tallied and entered into Table 1. Stems were grouped by DBH values and then plotted in a graph (Graph 1) against the number of stems per .05 hectares to show size distribution and frequency. The coordinate data collected was used along with DBH calculations to create five bubble charts mapping out the location, species, and DBH values of all stems in each 10 by 10 m plot (Figures 1-5). Results Graph 1 Figure 1 Conclusion Old growth oak forests in the eastern United States have been decreasing in recent years mostly due to fire suppression, deer browsing, and clearcutting. Fire suppression also allows for the increase in the red maple population. This is seen in the results from the five plots in WVU’s Experimental Forest where there are numerous small DBH red maples and few large DBH oaks. As fire suppression continues to occur, a transition from oak to red maple domination in forests will become more evident. To further demonstrate this transition, dendrochronological analysis is recommended to correctly age the stems. Periodic prescribed burnings are recommended to control the red maple population and allow for oak regrowth. In order to address the deer browsing problem, fencing off areas with new oak stems will keep browsing at a minimum and allow for more growth. The last two methods have been used in West Virginia’s Fernow Experimental Forest. Background Old growth oak (Quercus spp.) forests are disappearing across the eastern United States due to fire suppression. Fire not only allows for oak regeneration but it also keeps the subcanopy clear of any competing trees. Oaks are xerophytic species that require light and do not respond well to competition in the canopy. Without fire, shade tolerant species such as the red maple (Acer rubrum) dominate the subcanopy. As these trees become larger, they push their way into the canopy and overpower the remaining oaks. Clearcutting and browsing by the increasing population of white tailed deer also contribute to the lack of oak regeneration. White tailed deer have a preference for oak acorns over the stems of red maples (Abrams, 1998). Red maple is an opportunistic species that can adapt in many different environments and easily transitions from the shade of the subcanopy to the well lit canopy of a forest. Figure 2 Figure 3 Figure 4 Figure 5 From the five 10x10 permanent plots, 78.68% of the trees present were Red Maple. Oak species and Black Cherry (Prunus serotina) made up the majority of the rest, each representing 9.56% of the trees present. Tulip poplar (Liriodendron tulipifera), black gum (Nyssa sylvatica), and American beech (Fagus grandifolia) represented the last 2.22% of the population. When the frequency of each tree species was graphed against a DBH range, it became clear that the majority of the Red Maples fell under that smallest DBH range of 0-9.99 cm. The Black Cherry had the second largest frequency in that range. The largest diameter tree within the five plots was an Oak, which was in the 80-89.99 DBH range category. In Figure 1, 12 of the 38 trees are missing from the plot area. Four of these trees had no coordinates and eight of the trees were recorded outside of the 10x10 permanent plot. Acknowledgements Thank you to the students from KSU and ISU for field data collection. References Abrams, Marc D. "The Red Maple Paradox." BioScience 48, no. 5 (1998): 355-364. http://www.jstor.org/stable/1313374 (accessed Jul 21, 2009) Abrams, Marc D., David A. Orwig, and Thomas E. Demeo. "Dendroecological analysis of successional dynamics for a presettlement-origin white-pine-mixed-oak forest in the southern Appalachians, USA." Journal of Ecology 83 (1995): 133-43 Background picture: http://www.treegrowersdiary.com