资源环境科技发展态势分析平台

Overstory and understory treatments were established in natural oak stands and red pine plantations in Michigan in 1991 to test the hypotheses that (1) oak seedling survival and growth would be greater in pine than oak stands and (2) removal of competitors would enhance oak seedling performance. Late spring prescribed fires were implemented in 2002 and 2008 to investigate their effectiveness in controlling understory red maple. Performance of planted northern red oaks has been monitored since 1991 and the abundance of naturally regenerating oak and red maple seedlings and sprouts in different size classes has been documented since 2001. A subset of oaks has been protected against deer browsing since planting. Results suggest partial competitor removal enhances oak seedling and sprout performance, whereas complete removal increases mortality from browsing and frost. Increases in red maple abundance and decreases in oak abundance were documented after the prescribed fires in 2015. Greater growth and survival of planted oaks was observed in the pine stands, provided they were protected from browsing. Based on these results, the most viable management scenario for maximizing survival and growth of oak seedlings and sprouts in the study region would include protecting oak seedlings from deer in 25% canopy cover shelterwoods in pine plantations. Opportunities exist for developing systems involving alternating rotations and mixtures of oak and pine.