Eastern National Parks protect regionally significant older forest habitat

Seirup, Camilla; Miller, Kate; Weed, Aaron

From the abstract: "Forests in the eastern United States perform essential ecosystem services, provide food and habitat for countless organisms, and generate significant economic benefits to the region. In this study, we asked whether the protection status of parks (i.e. protected from logging) has resulted in structural forest differences compared with surrounding unprotected forests, which we refer to as matrix forests. We analyzed land-cover and forest vegetation data from nearly 25,000 permanent plots distributed across 50 national parks in the eastern United States, along with the matrix around each park, to examine structural characteristics of park forests in relation to their surrounding landscape. Over 2,000 of these plots are part of the National Park Service (NPS) Inventory and Monitoring Program (I&M), and the remaining 22,500+ plots are part of the US Forest Service (USFS) Forest Inventory and Analysis (FIA) Program. Results of this study indicate that, regardless of the type of national park (National Historical Park, National Monument, National Park, etc.), the majority of park forests are distinct from surrounding matrix forests. Park forests consistently had greater proportions of late-successional forest, greater live tree basal area, greater densities of live and dead large trees, and considerably larger volume of coarse woody debris. Park forests also had lower tree growth and mortality rates than matrix forests, which is also suggestive of older forests. Based on studies of habitat requirements for late successional bird species and organisms dependent on dead wood, the differences in park and matrix forests are ecologically significant, with park forests protecting critical habitats that are otherwise deficient on the landscape. We therefore recommend that park managers continue to allow for natural disturbances and the development of complex forest structure in park forests despite potential outside pressure from the public or other park decision-makers to “clean up” the forest after disturbances such as windthrow or ice storms. Moving forward, eastern forests will continue to respond to climate change and other stressors, and the trends captured by long-term NPS I&M monitoring programs will provide valuable scientific insights into forest dynamics and important guidance for land managers."