Multi-species Planting and Other Practices to Restore Forest Diversity in Northeastern Minnesota

Abstract

Forest stand diversification in terms of plant species and spacing of plantings is critical to restoring components of native forests, reducing risks of insect and disease outbreaks, and providing a variety of habitats for native birds and other forest animals. We share the results of experimentation with reforestation practices to achieve more diverse upland forests in northeastern Minnesota. We also share the results of a study to determine the impact of site preparation (rock raking) and seedling “release” (removing competing surrounding vegetation after two years) on survival and height of 19 native trees and shrubs. After five years, seedling survival across the 19 species ranged from 31% to 94%, with mean of 72%. Survival was higher for sites receiving the preparation treatment (76%) than for those not receiving the treatment (68%). Site preparation significantly increased seedling height for eight species. In year three of the study we removed nearby competing vegetation (release treatment), which resulted in significantly greater seedling height for two species and less height growth for three species after two years. We discuss the value of increases in survival and height in the context of overall forest management objectives and other management strategies to diversify forest species and structure.