Christel C. Kern

Long-Term Research at the USDA Forest Service's Experimental Forests and Ranges

Abstract The network of experimental forests and ranges administered by the US Department of Agriculture Forest Service consists of 77 properties that are representative of most forest cover types and many ecological regions in the nation. Established as early as 1908, these sites maintain exceptional, long-term databases on environmental dynamics and biotic responses. Early research at these sites focused on silviculture, ecosystem restoration, and watershed management. Over time, many of the properties have evolved into a functional network of ecological observatories through common large-scale, long-term experiments and other approaches. Collaboration with other institutions and research programs fosters intersite research and common procedures for managing and sharing data. Much current research in this network focuses on global change and interdisciplinary ecosystem studies at local to global scales. With this experience in developing networks and compiling records of environmental history, the experimental forests and ranges network can contribute greatly to formation of new networks of environmental observatories.

Growth, yield, and structure of extended rotation Pinus resinosa stands in Minnesota, USA.

Extended rotations are increasingly used to meet ecological objectives on forestland; however, information about long-term growth and yield of these systems is lacking for most forests in North Ame...

A cross‐continental comparison of plant and beetle responses to retention of forest patches during timber harvest

Timber harvest can adversely affect forest biota. Recent research and application suggest that retention of mature forest elements (retention forestry), including unharvested patches (or aggregates) within larger harvested units, can benefit biodiversity compared to clearcutting. However, it is unclear whether these benefits can be generalized among the diverse taxa and biomes in which retention forestry is practiced. Lack of comparability in methods for sampling and analyzing responses to timber harvest and edge creation presents a challenge to synthesis. We used a consistent methodology (similarly spaced plots or traps along transects) to investigate responses of vascular plants and ground-active beetles to aggregated retention at replicate sites in each of four temperate and boreal forest types on three continents: Douglas-fir forests in Washington, USA; aspen forests in Minnesota, USA; spruce forests in Sweden; and wet eucalypt forests in Tasmania, Australia. We assessed (1) differences in local (plot-scale) species richness and composition between mature (intact) and regenerating (previously harvested) forest; (2) the lifeboating function of aggregates (capacity to retain species of unharvested forest); and whether intact forests and aggregates (3) are susceptible to edge effects and (4) influence the adjacent regenerating forest. Intact and harvested forests differed in composition but not richness of plants and beetles. The magnitude of this difference was generally similar among regions, but there was considerable heterogeneity of composition within and among replicate sites. Aggregates within harvest units were effective at lifeboating for both plant and beetle communities. Edge effects were uncommon even within the aggregates. In contrast, effects of forest influence on adjacent harvested areas were common and as strong for aggregates as for larger blocks of intact forest. Our results provide strong support for the widespread application of aggregated retention in boreal and temperate forests. The consistency of pattern in four very different regions of the world suggests that, for forest plants and beetles, responses to aggregated retention are likely to apply more widely. Our results suggest that through strategic placement of aggregates, it is possible to maintain the natural heterogeneity and biodiversity of mature forests managed for multiple objectives.

Development of the Selection System in Northern Hardwood Forests of the Lake States: An 80-Year Silviculture Research Legacy

The northern hardwood research program at the Dukes Experimental Forest in Michigan and Argonne Experimental Forest in Wisconsin has been adapting to changing management and social objectives for more than 80 years. In 1926, the first northern hardwood silviculture study was established in old-growth stands at the Dukes Experimental Forest. In response to social demands for more “natural” forestry, the study included then-contemporary practices (e.g., liquidation of old-growth forest) and new approaches (e.g., partial cuttings). By 1953, the partial cutting treatments were deemed most sustainable (Eyre and Zillgitt, Partial cuttings in northern hardwoods of the Lake States: twenty-year experimental results. Technical Bulletin LS-1076, 1953), and led to the creation of an uneven-aged stand structural guide that is still widely used today: the famed “Arbogast Guide” (Marking guides for northern hardwoods under the selection system. Station Paper 56, 1957). Charismatic figures such as Raphael Zon, Windy Eyre, William Zillgitt, and Carl Arbogast Jr. were important to establishing this research and its early application in the Lake States region. Since then, research at the Dukes and Argonne Experimental Forests has expanded to evaluate a range of management alternatives for northern hardwood forests, including approaches designed to sustain biodiversity, habitat, and timber production. In addition, the long-term studies provide new opportunities for larger-scale applications and research unforeseen at the studies’ establishment. The lessons learned from the 80 years of research on northern hardwood ecosystems at the Dukes and Argonne Experimental Forests have led to numerous publications and management guides and have impacted thousands of forestry professionals and millions of hectares of land.