Relationships Between Overstory and Understory Tree Composition and Light Environment in an Old Growth Forest, Adirondacks, NY

Density of tree seedlings and saplings can be considerably influenced by light availability and the overstory canopy composition. We examined whether forest understory light environment could be predicted by overstory composition in an old growth northern hardwood forest at Huntington Wildlife Forest in the central Adirondacks, NY. We also tested whether the overstory composition and light environment could be used to predict the understory tree composition. Existing continuous forest inventory data were used to quantify the overstory and we collected additional data on tree seedlings and saplings. We characterized the light environment using hemispherical canopy photography. Percent canopy openness was positively correlated with the proportion of American beech (Fagus grandifolia) in the overstory. Understory tree species richness was not predicted by light environment or by the overstory. Yet seedling and sapling density of certain tree species could be predicted by certain overstory characteristics. Density of understory beech was positively correlated with the proportion of overstory beech basal area; however, the densities of other tree species in the understory were not as well correlated with the proportion of overstory conspecifics. Understanding these relationships may help shed light on factors influencing regeneration dynamics in this Adirondack old growth forest. Additionally, since forests in the region have been impacted by beech bark disease the results of this study help elucidate the overstory-understory dynamics in the presence of this disturbance