The effect of active and passive restoration strategies on the species composition of a hardwood forest

Less than 10% of Minnesota’s hardwood forests remain after heavy logging in the 19 and early 20 centuries. In order to ensure that this ecosystem continues to be a part of Minnesota’s natural history, forest managers have begun practicing active and passive restoration. The composition of a remnant forest, planted forest, and an adjacent old-field in the St. Olaf College Natural Lands, was analyzed to understand the effect of active and passive restoration on the composition of the forests. Forest composition data was collected using quadrat and point-quarter methods. Mature trees were measured for their DBH and distance from the point, to calculate importance values. Soil data was collected and analyzed for percent moisture, organic matter, and bulk density. Data indicated that red oak and white oak were important in all forests, but were more abundant as mature trees than as seedlings or saplings. The composition of the planted forest was statistically different (p<0.05) than the remnant for mature tree composition and different than both remnant and old-field forests in sapling composition. The planted forest had higher diversity for seedlings and saplings, while the remnant had the highest for mature trees. Soil data indicated that the planted forest had lower percent moisture and percent organic matter than the remnant and old-field forest plots. These results indicate that the forest composition for planted and oldfield forests will change toward compositions similar to the remnant forest.