The presettlement vegetation of much of Warren Dunes State Park in southwestern Michigan is thought to have been mostly a dry-mesic southern forest of oaks and hickories. Since the 1800s, the forests probably have been logged at least once, if not more often, after which the forests began to undergo secondary succession. The objectives of the current study were to determine if successional changes are still occurring and what the future composition of the forest might look like as a consequence of those changes. Relative densities of species of trees in the canopy and the understory layers, sampled along transects in the upland forested areas of the dunes were used to determine the successional status of the forest and to predict its future composition. Currently, the forest is dominated in both the canopy and the understory layers by Quercus rubra L. and Acer saccharum Marshall. Comparisons of the relative densities of species in the canopy layer with those of species in the understory layer showthat the forest is in some mid- to late-successional stage. When absolute densities were plotted against size classes, a negative exponential distribution resulted, suggesting that the forest is replacing itself. Future changes in the composition and structure of the forest are explained relative to species characteristics and interactions.
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