Don Radcliffe's Graduate Exit Seminar
Don will present his Graduate Exit Seminar, Out with the Old Forest, In with the New: Environmental Factors Associated with Oak and Hickory Mortality and Maple and Beech Regeneration in Mature Forests of Appalachian Ohio, on Thursday, April 11, 2019 at 10 AM in Kottman 460.
Ecologically valuable oak and hickory trees are failing to replace themselves in the eastern U.S., likely due to fire suppression and a relatively wet climate during the past century. In 2016-2018, we resampled permanent plots first established in 1993-1995, in mature forests of the Wayne National Forest. We modeled mortality patterns of five oak and one hickory species, and sapling density patterns of three common shade-tolerant tree species. Our mortality results showed that all species of the red oak subgenus had relatively high mortality rates. Models indicated that white oak, chestnut oak and pignut hickory mortality was associated with competition, while northern red oak mortality was associated with mesic topographic positions and older stand ages. Our sapling results showed that American beech nearly doubled in density between the two sampling periods, while both red maple and sugar maple halved in density. Models indicated that soil acidity was positively correlated with red maple density, and negatively associated with sugar maple density, while higher slope positions were positively correlated with red maple density and negatively correlated with American beech density. These results show that stand structure may be more important than soil and topography in explaining mature tree mortality of most oak species, and that that topographic and acidity gradients are likely to partially explain future relative dominance patterns of red maple, sugar maple, and American beech.