Since 2021, Great Peninsula Conservancy’s (GPC) stewardship team has girdled over 800 trees across eight preserves. Tree girdling is the process of cutting strips of bark from a tree so that the dying tree provides valuable habitat for local wildlife and helps to open dense stands of forest.Evaluating Habitat Improvements
This work was funded through the Natural Resources Conservation Services (NRCS) Conservation Stewardship Program (CSP) and Cornell Lab of Ornithology’s Land Trust Bird Conservation Initiative (Cornell). To assess the efficacy of these habitat features, Cornell funded two internships with University of Washington Environmental Studies students this summer. The interns, Maya Clauson-Nehus and Abby Rocke, worked with GPC’s stewardship team to assess the efficacy of those built wildlife habitat features.
From June through August, Maya and Abby visited all eight preserves with staff to collect data, braving tough site conditions in deep summer. Their goal was to assess the functionality of tree girdling, develop best practices, and share findings with other conservation organizations.
Maya and Abby visited 150 girdled trees, looking to see whether tree health was affected. They collected data such as girdle width, and the height, diameter, and depth of the cut to assess what may have contributed to an individual tree’s death. Their data analysis highlighted the need to follow up over a longer timeframe to fully evaluate whether the girdled structures were functioning as designed.
The results were a catalyst for Abby and Maya to engage in a rigorous assessment of the project and the study design. They provided valuable insights, encouraging further exploration of specific management goals for individual properties based on their unique site characteristics. They suggest that a better understanding of environmental conditions at each property, including different variables and site conditions (such as the presence of root rot pathogen), paints a more complete picture to inform the success or failure of girdling. Additionally, they established key suggestions for GPC and partners to consider in the project-planning phase including urging forest managers to incorporate interdisciplinary research (such as invertebrate response to girdling), and to more clearly define “success” in forest management activities.
Thanks to Abby and Maya’s dedicated work, GPC’s team continues to refine our forest management goals and opportunities, and we look forward to sharing what comes next.
