Prescribed fire is increasingly viewed as a valuable tool for reversing ecological consequences of fire suppression within fire-adapted forests. While the use of burning treatments in northern temperate conifer forests has received considerable attention, the long-term (>10 year) effects on understory composition and dynamics have not been quantified. We describe the persistence of prescribed fire effects on the woody and herbaceous understory in a mature red pine (Pinus resinosa Ait.) forest in northern Minnesota, USA, over a ~50-year period, as well as the relative roles of fire season and frequency in affecting vegetation responses. Burning treatments were applied from 1960 to 1970 on 0.4 ha experimental units and crossed fire season and frequency in a randomized block design. Burning altered shrub layer dynamics and composition in both the short and long terms and was influenced by both fire season and frequency, with frequent summer season burns having the largest impact, including greatest control of hazel (Corylus spp.). The application of fire facilitated regeneration of pine; however, recruitment into the overstory was limited. Additionally, community composition of the herbaceous understory diverged 40+ years following burning. This study highlights the importance of continued burning in affecting vegetation responses and the potential of fire as a long-lasting vegetation management tool in these forests.
Bibliographical noteFunding Information:
We would like to thank Robert Buckman for envisioning and establishing this study in 1959 and Doug Kastendick and many other scientists and technicians at the USDA Forest Service (USFS) Northern Research Station for collecting and maintaining inventory records throughout the duration of the study. Valuable field assistance in 2014 was provided by Bryten Felix. Discussion and comments from members of the University of Minnesota’s Silviculture and Applied Forest Ecology Lab have greatly improved the scope and direction of this work. Scott Weyenberg, Jessica Miesel, and Laura Kenefic provided comments on an earlier draft of this article that greatly clarified and strengthened this work. Funding that made this work possible was provided by the USFS Northern Research Station and USFS State and Private Forestry Evaluation Monitoring Program. Additional financial support was provided by the University of Minnesota’s Department of Forest Resources through the Henry Hansen Forest Ecology Fellowship and the Catherine Hill Fellowship in Forest Resources and the Minnesota Agricultural Experiment Station.
- Controlled burn
- Corylus spp
- Long-term study
- Vegetation control