Warren Forestry Sciences Laboratory

Forest Renewal

Forest Renewal The key to sustaining forests is successfully renewing all their elements after disturbance, across landscapes and through time. We are working to strengthen our understanding of the relationships among certain elements of forest communities in stands and forests of different ages, species compositions, and disturbance history and patterns. Specifically, we are building on our databases and mechanistic understanding of woody and herbaceous plants, songbirds, small mammals, amphibians and forest carbon. We need to understand the factors that control regeneration and renewal of each of these communities, the responses of these communities to disturbance, and the impacts of selected disturbances on forest carbon pools and sequestration rates. We need to provide managers with tools to ensure diverse new forests, for a variety of management objectives. This research includes understanding the implications of forest regeneration practices on many wildlife and herbaceous communities.

A photo showing tall forest regeneration inside of a fence with nothing growing outside of the fence demonstrating the negative influence of deer browsing Early research by this Research Work Unit produced guidelines for assessing the adequacy of advance regeneration prior to a stand-replacing disturbance in Allegheny hardwood stands, and a systematic approach to improving advance regeneration where surveys showed it to be inadequate. These guidelines depended heavily on the silvical characteristics of black cherry and the high light conditions associated with even-aged silviculture, because this combination sometimes provided the only way to regenerate in the face of heavy white-tailed deer browsing. Widespread adoption of these guidelines improved the success of forest managers in regenerating Allegheny hardwood stands fully stocked with trees. We need to refine these guidelines and prescriptions to increase their utility for renewing stands with a diversity of woody species. We also need to develop and test similar guidelines for other forest types, especially oak forests. We need to refine these guidelines for application with two-age, multi-age or small-patch silvicultural systems. We need to identify the threshold basal areas required to ensure successful regeneration for important species. This work is especially needed on private land, where timber harvesting practices over the last thirty years have sometimes focused more on removing high value species than on sustaining forests, and guidelines are required for assessing and restoring forest productivity. Furthermore, there is great interest in understanding the responses of the wildlife and herbaceous plant communities to the prescriptions undertaken to ensure valuable forest tree regeneration. And while we have documented the impacts of deer on forest communities in some detail, we have not linked this research to understanding of deer or hunter behavior. Our research on this problem addresses all these needs, and follows four main tracks:

  1. We are testing and refining guidelines for enhancing the proportion of oak species in the regeneration of oak forests.

    Working with researchers and forest managers from other Forest Service units, from the Pennsylvania State University, and from the Pennsylvania DCNR Bureau of Forestry, we have developed interim guidelines for assessing and enhancing the proportion of oak species in regenerating oak forests. We will work with practitioners in the Bureau of Forestry and with our research partners to test and improve those guidelines, and to conduct the basic research required to validate the interim prescriptions. In particular, we have recently launched a study of the development of root and shoot development in oak seedlings under a variety of different lighting conditions, and we hope to assess the impact of common silvicultural treatments (herbicide application, prescribed fire, thinning, shelterwood seed cuts) on the regeneration and renewal of plant communities in oak forests.

    Our partners in this research include Research Work Units NE-4557 (Morgantown, WV) and NE-4353 (Parsons, WV), the Pennsylvania DCNR Bureau of Forestry, the Pennsylvania State University, the Pennsylvania Game Commission, the Allegheny National Forest, Kane Hardwoods, a Collins Company, Forest Investment Associates, Inc., and the Connecticut Agricultural Experiment Station. This work will be conducted primarily at the stand and research plot level.

  2. We are developing guidelines for regenerating new stands with more diverse woody species composition, including guidelines for some stands without abundant black cherry seed source.

    Previous research shows that when deer impact is reduced or controlled by fencing, light is the next most limiting resource for regeneration of many species. Anecdotal evidence from our research suggests that while for black cherry, seedling establishment occurs by the time a seedling reaches two inches in height, for other species, other size thresholds might be more appropriate. We plan to revisit data from previous studies within fences and, where resources permit, install new studies to test the advance regeneration requirements and revisit size thresholds of key forest tree species, including red maple, white ash, and eastern hemlock.

    We also plan to continue to assess the development of regeneration under uneven-age, two-age, and no cutting silvicultural systems. This work will include continued monitoring of existing studies and the Tionesta and Hearts Content special management areas of the Allegheny National Forest, and some new studies. We need to assess the adequacy of existing advance regeneration assessment techniques for predicting responses to natural disturbances and non-stand-replacing harvests.

    Primary partners in this work presently are the Allegheny National Forest, Forest Investment Associates, Forecon, Inc., Potter Lumber Company, the State University of New York, and the Pennsylvania Bureau of Forestry. We plan to conduct this research primarily at the stand or research plot level.

  3. We are learning more about floral and faunal communities of early successional forests, emphasizing herbaceous plants, songbirds, amphibians, and small mammals.

    The overall objective of our wildlife habitat research is to develop verified, quantitative indicators of habitat quality for individual bird, small mammal, and amphibian species. From these, we plan to develop tools for land and resource managers to assess these factors during forest inventories. For our studies of herbaceous communities, we are interested in characterizing these communities for Allegheny Plateau forests, and characterizing their responses to silvicultural treatment.

    Through the present, this work has focused on the responses of floral and faunal communities to forest renewal treatments, and consists of two main studies. One is a study of impacts of herbicide/shelterwood and shelterwood/herbicide sequences on non-target organisms, including amphibians, small mammals, songbirds, and herbaceous plants. The second is a characterization of stand characteristics and songbird, amphibian, and herbaceous plant communities in a chronosequence of Allegheny Plateau stands from early successional to true old-growth. In addition, we are monitoring some or all of these communities in some of our uneven-age silviculture research studies. As a result of this work, we have an extensive database of wildlife and herbaceous plant communities in Allegheny Plateau forests. We intend to analyze and report the relationships revealed by this rich database to increase the understanding of forest managers, conservation interests, and policy makers about the underlying ecological relationships in these forest communities.

    As resources permit, we will add focused studies on the natural history of organisms, such as the chestnut sided-warbler, that depend on habitat components found exclusively in early-successional forests. Market forces on private land and policy decisions on public land are reducing such forests in relative abundance on the landscape.

    Primary partners for this work are the Allegheny National Forest, the Research Natural Area program of Region 9, US Forest Service, the NAPIAP program of US Forest Service State and Private Forestry, the Morris Arboretum, and the Biodiversity Program of the Pennsylvania Department of Conservation and Natural Resources. The scale for this research will be forest stands, although we will also explore the influences of neighboring landscapes on stand responses.

  4. We are refining existing guidelines and developing new ones appropriate to conditions on private land.

    Prescriptions and guidelines developed to date at this lab have focused on conditions in forests in which sustainable management had been practiced for several decades. Such practices are common on public forests and on long-term, large-scale industrial ownerships. In Allegheny hardwood forests, such stands have high basal areas of seed producing trees, and occur in large blocks that lend themselves to even-aged silviculture at the stand level. Forests on private land differ in one or two respects: many acres have been abusively harvested in the past, and contain only limited overstory seed source, especially for species of high commercial timber value; and many private owners are resistant to the creation of large, early-succesional patches. We will review previous and on-going studies to develop threshold levels for seed source for key forest species, such as white ash, sugar and red maple, and northern red oak, to help land managers identify situations in which natural regeneration will need to be supplemented with artificial regeneration, such as direct seeding or hardwood planting or interplanting. We will form partnerships with organizations, such as the Hardwood Regeneration and Tree Improvement Center at Purdue University and the State Univeristy of New York, to encourage research on artificial regeneration for Allegheny Plateau forests. And we will continue to study alternatives to even-age management. The intensity of this work, especially in terms of new studies, will depend on level of funding.

    Principal partners in this research are Forest Investment Associates, Inc., the Potter Lumber Co., Forecon, Inc., the Pennsylvania DCNR Bureau of Forestry, the Purdue University/USFS Hardwood Regeneration and Tree Improvement Center, the State University of New York College of Environmental Science and Forestry, and Kane Hardwoods, a Collins Co.

  5. We continue to develop and refine our understanding of interactions among deer, forest vegetation, and deer management policies, primarily through our partnerships and participation in the Quality Hunting Ecology Study led by the Sand County Foundation.

    Our research work unit has produced some of the best data available documenting the impacts of deer on forested ecosystems as a result of our ten-year study using known densities of deer enclosed in managed forests. Results from that study continue to be analyzed and reported. In recent years, we have been active participants in the development and implementation of a landscape-scale study of the interactions among deer, forest vegetation, water quality, deer management policies, and hunter attitudes and behaviors. Lab scientists have been active in developing the vegetation monitoring protocols for this study, and the conceptual model that frames the study. We have also cooperated in the establishment and early public involvement for a 50,000-acre study site of mixed private and public land in the northeast corner of the Allegheny National Forest. We will continue our participation in this study and associated data analysis and reporting.

    In addition, we are continuing to measure the response of tree and herbaceous plant species, songbirds, and deer density to intensified cutting within a compartment of the Allegheny National Forest.

    Primary partners for this work at present are the Sand County Foundation, the Pennsylvania DCNR Bureau of Forestry, the Pennsylvania Game Commission, the Allegheny National Forest, the Society of American Foresters Deer/Forest/Farm Committee, Kane Hardwoods, a Collins Co., and Keith Horn, Inc. This research will necessarily occur at the stand, stand aggregate and landscape scale.

  6. We are improving our understanding of how forest carbon pools and sequestration rates are affected by stand replacing disturbances.

    We have begun a study of soil carbon pools in stands from 15 to 180 years after natural disturbance within the Tionesta Scenic and Research Natural Area. We also hope to remeasure soil carbon in stands near the Tionesta Scenic and Research Natural Area on plots originally measured by Ash Hough in the 1930s.

    Primary partners in this work include the US Forest Service Global Change Program, the US Department of Energy NREL Lab in Colorado, and the Allegheny National Forest. We will conduct this work at both the stand, and through modeling, at the landscape level.

Send comments or inquiries to: cweldon@fs.fed.us.


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Last updated Februray 28, 2001.