John C. Brissette

Woody debris volume depletion through decay: Implications for biomass and carbon accounting

Woody debris decay rates have recently received much attention because of the need to quantify temporal changes in forest carbon stocks. Published decay rates, available for many species, are commonly used to characterize deadwood biomass and carbon depletion. However, decay rates are often derived from reductions in wood density through time, which when used to model biomass and carbon depletion are known to underestimate rate loss because they fail to account for volume reduction (changes in log shape) as decay progresses. We present a method for estimating changes in log volume through time and illustrate the method using a chronosequence approach. The method is based on the observation, confirmed herein, that decaying logs have a collapse ratio (cross-sectional height/width) that can serve as a surrogate for the volume remaining. Combining the resulting volume loss with concurrent changes in wood density from the same logs then allowed us to quantify biomass and carbon depletion for three study species. Results show that volume, density, and biomass follow distinct depletion curves during decomposition. Volume showed an initial lag period (log dimensions remained unchanged), even while wood density was being reduced. However, once volume depletion began, biomass loss (the product of density and volume depletion) occurred much more rapidly than density alone. At the temporal limit of our data, the proportion of the biomass remaining was roughly half that of the density remaining. Accounting for log volume depletion, as demonstrated in this study, provides a comprehensive characterization of deadwood decomposition, thereby improving biomass-loss and carbon-accounting models.

Putting community data to work : some understory plants indicate red spruce regeneration habitat

When harvested, red spruce (Picea rubens) at low elevations is vulnerable to temporary displacement by balsam fir (Abies balsamea) and hardwoods. If indicator plants can be found by which to assess spruce regeneration habitat, then biota dependent on red spruce dominance could benefit. Associations between spruce seedlings (0.1‐0.5 m tall) and understory plants, species life histories, and successional processes can be considered in managing for biodiversity; species richness alone is inadequate. Data from eight Maine sites in 50 permanent 0.0625 ha plots and 600 1 m 2 subplots along a disturbance gradient included 30 understory species and nine environmental variables. In a canonical correspondence analysis (CCA), the first two canonical axes accounted for 64.6% of the species‐environment relationship; their eigenvalues accounted for 22% of the total variation. Spruce seedlings were sparse in clearcuts and most abundant in stands that were partially harvested at20 year intervals and where Curtis’ Relative density, softwood:hardwood ratio, and percent of understory plants visited by bees were all high. We propose a suite of common, widespread herbs and a liverwort as potential indicators, but recognize that parent trees probably influence red spruce seedling density more than does ground flora composition. # Published by Elsevier Science 1999.

Nonnative invasive plants in the Penobscot Experimental Forest in Maine, USA: influence of site, silviculture, and land use history.

Abstract We investigated the occurrence of nonnative invasive plants on approximately 175 ha comprising a long-term, 60-year-old U.S. Forest Service silvicultural experiment and old-field stands in the Penobscot Experimental Forest (PEF) in central Maine. Stands in the silvicultural experiment were never cleared for agriculture, but have been repeatedly partially cut. Our objectives were to determine the extent of nonnative invasive plant populations in the PEF, and to relate invasive plant abundance and distribution to management history and environmental factors (overstory composition and basal area, canopy openness, and soil characteristics). We found ten invasive plant species in the study area. Very few occurrences of these were in the silvicultural experiment; where present, invasive plants there appear to be associated with proximity to seed source, and a greater degree of recreational or silvicultural disturbance. Ordination showed that the environmental variables which were associated with invasive species in the old fields were not associated with the presence of invasives in the silvicultural treatments. In the old-field stands, invasive plant cover was positively related to exposed mineral soil and negatively related to organic horizon thickness; invasive plant richness was negatively related to hardwood litter cover. Frangula alnus was the most frequent invasive plant species in both the old-field stands and silvicultural experiment; its distribution was not correlated with observed environmental variables. Control measures are recommended to prevent further encroachment of invasive plants into the silvicultural experiment.

Influence of Drought Stress on the Response of Shortleaf Pine to Ozone

The gaseous composition of the atmosphere has changed significantly during the past century as the result of anthropogenic activity. Changes in the physical and chemical climate of the southern United States may have significant detrimental effects on the forest tree species that grow in this extensive and complex region. Although the consequences of these changes for forest ecosystems are manifold, the most significant outcomes may be 1) chronic exposure of ecologically and economically important species to elevated levels of phytotoxic pollutants, and 2) global and regional scale changes in precipitation regimes. Knowledge of the combined impacts of the climatic and air pollutant stresses on forests and forest species is essential to ensuring their productivity and sustainability.

Experimental forests and ranges : 100 years of research success stories

In 2008, Forest Service Research and Development celebrated the Centennial Anniversary of these Experimental Forests and Ranges. This publication celebrates the many scientists who over the course of decades conducted the long-term studies that began and are continuing to shed light on important natural resource issues. Story suggestions were solicited from the Experimental Forest and Range Working Group and were selected to demonstrate the array of research issues being addressed on these living laboratories. Gathering a wealth of information from her interviews with scientists, Gail Wells proceeded to write these “…wonderful success stories from 100 years of research.” Studies established decades ago on many of these sites are still going strong. Experimental forests and ranges provide a valuable, long-term stream of information about the land and its resources. Over the years, researchers have built an impressive body of science to support good land management and further understanding of natural processes. Their research sheds light on many important questions. These experimental forests serve as living laboratories that help us connect the future to the past.

Vegetation of forested uplands in the Massabesic Experimental Forest

A summary of an inventory of vascular plants in the 3,700-acre Massabesic Experimental Forest in York County, Maine. We identified about 500 species and subspecies. The most common overstory trees were eastern white pine, eastern hemlock, northern red oak, and red maple. Hemlock was the most abundant tree seedling. Shrub density was greatest for beaked hazlenut, followed by several viburnum species, highbush blueberry, and winterberry. The most common herb was starflower. We found nine listed rare plants, including a federally threatened orchid, small whorled pogonia. A geographic information system was developed and includes inventory data, forest type, soils, fire history, topography, roads, and streams.

Dendroclimatic analysis of white pine (Pinus strobus L.) using long-term provenance test sites across eastern North America

BackgroundThe main objective of this study was to examine the climatic sensitivity of the radial growth response of 13 eastern white pine (Pinus strobus L.) provenances planted at seven test sites throughout the northern part of the species’ native distribution in eastern North America.MethodsThe test sites (i.e., Wabeno, Wisconsin, USA; Manistique, Michigan, USA; Pine River, Michigan, USA; Newaygo, Michigan, USA; Turkey Point, Ontario, Canada; Ganaraska, Ontario, Canada; and Orono, Maine, USA) examined in this study were part of a range-wide white pine provenance trial established in the early 1960s in the eastern United States and Canada. Principal components analysis (PCA) was used to examine the main modes of variation [first (PC1) and second (PC2) principal component axes] in the standardized radial growth indices of the provenances at each test site. The year scores for PC1 and PC2 were examined in relation to an array of test site climate variables using multiple regression analysis to examine the commonality of growth response across all provenances to the climate of each test site. Provenance loadings on PC1 and PC2 were correlated with geographic parameters (i.e., latitude, longitude, elevation) and a suite of biophysical parameters associated with provenance origin location.ResultsThe amount of variation in radial growth explained by PC1 and PC2 ranged from 43.4% to 89.6%. Dendroclimatic models revealed that white pine radial growth responses to climate were complex and differed among sites. The key dendroclimatic relationships observed included sensitivity to high temperature in winter and summer, cold temperature in the spring and fall (i.e., beginning and end of the growing season), summer moisture stress, potential sensitivity to storm-induced damage in spring and fall, and both positive and negative effects of higher winter snowfall. Separation of the loadings of provenances on principal component axes was mainly associated with temperature-related bioclimatic parameters of provenance origin at 5 of the 7 test sites close to the climate influence of the Great Lakes (i.e., Wabeno, Manistique, Pine River, Newaygo, and Turkey Point). In contrast, differences in radial growth response to climate at the Ganaraska test site, were driven more by precipitation-related bioclimatic parameters of the provenance origin location while radial growth at the easternmost Orono test site was independent of bioclimate at the provenance origin location.ConclusionsStudy results suggest that genetic adaptation to temperature and precipitation regime may significantly influence radial growth performance of white pine populations selected for use in assisted migration programs to better adapt white pine to a future climate.

Sampling and measurement protocols for long-term silvicultural studies on the Penobscot Experimental Forest

The U.S. Forest Service, Northern Research Station has been conducting research on the silviculture of northern conifers on the Penobscot Experimental Forest (PEF) in Maine since 1950. Formal study plans provide guidance and specifications for the experimental treatments, but documentation is also needed to ensure consistency in data collection and sampling protocols. This guide details current sampling and measurement protocols for three of the longest running Forest Service experiments on the PEF: (1) the management intensity demonstration (1950 to present), (2) the compartment management study (1952 to present), and (3) the auxiliary selection cutting study (1953-present). Each of these long-term stand-scale experiments use plot-based measurements of trees taken at periodic intervals. Additional data collected vary and include regeneration, recruitment, and mortality; amount, size, and decay of dead wood; and stand structural characteristics such as heights, crown dimensions, and spatial locations of trees. Descriptions provided here are the basis for data collection in the relevant studies on the PEF, inform interpretation of the published databases, and serve as a model for silvicultural studies elsewhere.

Northeastern Conifer Research: Multiple Species and Multiple Values

The northern conifer, or spruce-fir, forest of the northeastern USA and adjacent Canada has had a defining influence on the economy and culture of the region. The same can be said of the USDA Forest Service’s research in this forest, which began more than 100 years ago. Forest Service research has evolved since that time in response to changes in the needs and prominence of the forest industry, and in public attitudes and concerns. Early studies of forest protection and rehabilitation first gave way to mid-century research on production forestry, then to twenty-first-century research on forest ecology. Though various lines of research have come and gone, long-term studies on the region’s experimental forests continue to provide a unique perspective on the structure and dynamics of the forest, and the outcomes of silvicultural alternatives.