William H. McWilliams

Neighborhood Analyses Of Canopy Tree Competition Along Environmental Gradients In New England Forests

We use permanent-plot data from the USDA Forest Services Forest Inventory and Analysis (FIA) program for an analysis of the effects of competition on tree growth along environmental gradients for the 14 most abundant tree species in forests of northern New England, USA. Our analysis estimates actual growth for each individual tree of a given species as a function of average potential diameter growth modified by three sets of scalars that quantify the effects on growth of (1) initial target tree size (dbh), (2) local environmental conditions, and (3) crowding by neighboring trees. Potential growth of seven of the 14 species varied along at least one of the two environmental axes identified by an ordination of relative abundance of species in plots. The relative abundances of a number of species were significantly displaced from sites where they showed maximum potential growth. In all of these cases, abundance was displaced to the more resource-poor end of the environmental gradient (either low fertility or low moisture). The pattern was most pronounced among early successional species, whereas late-successional species reached their greatest abundance on sites where they also showed the highest growth in the absence of competition. The analysis also provides empirical estimates of the strength of intraspecific and interspecific competitive effects of neighbors. For all but one of the species, our results led us to reject the hypothesis that all species of competitors have equivalent effects on a target species. Most of the individual pairwise interactions were strongly asymmetric. There was a clear competitive hierarchy among the four most shade-tolerant species, and a separate competitive hierarchy among the shade-intolerant species. Our results suggest that timber yield following selective logging will vary dramatically depending on the configuration of the residual canopy, because of interspecific variation in the magnitude of both the competitive effects of different species of neighbors and the competitive responses of different species of target trees to neighbors. The matrix of competition coefficients suggests that there may be clear benefits in managing for specific mixtures of species within local neighborhoods within stands.

The forests of Maine: 2003

In 1999, the Maine Forest Service and USDA Forest Services Forest Inventory and Analysis program implemented a new system for inventorying and monitoring Maines forests. The effects of the spruce budworm epidemic continue to affect the composition, structure, and distribution of Maines forested ecosystems. The area of forest land in Maine has remained stable since the 1970s. Although relatively small acreages of forest are converted to other land uses, these conversions often remove highly valued forests such as white pine. The total inventory volume of live trees increased slightly, indicating the beginning of a response of Maines forest to the tremendous devastation from spruce budworm.

Composition and vulnerability of bottomland hardwood forests of the Coastal Plain Province in the south central United States

Abstract A past history of declines in forest area affirms the need for documentation on the extent and species composition of todays bottomland hardwood ecosystem. This paper summarizes the forest composition and related vulnerability of bottomland hardwood forests using data from the many existing resource bulletins and the current inventory data base maintained by the USDA Forest Service. These forests support a complex mix of tree species. The 6.1 million-ha ecosystem is common in three physiographic sections of the Province. The East and West Gulf sections are typified by moist-site cover types, with stands widely dispersed. The Mississippi Alluvial Plain contains both moist- and wet-site cover types. Southern portions of the Mississippi Alluvial Plain are characterized by wet-site cover types with stands being concentrated spatially. Cover types are susceptible to varying degrees of human-induced disturbance, which may ultimately lead to permanent removal of forest cover.

Assessing sustainability using data from the Forest Inventory and Analysis Program of the United States Forest Service

Abstract Forest sustainability has emerged as a crucial component of all current issues related to forest management. The seven Montreal Process Criteria are well accepted as categories of processes for evaluating forest management with respect to sustainability, and data collected by the Forest and Inventory Analysis (FIA) program of the United States Forest Service are well suited for such evaluations. The FIA program focuses on the collection, analysis, and distribution of data for a core set of variables obtained using a plot configuration, a sampling design, and measurement protocols that all feature national consistency. Plot, subplot, and tree-level observations include traditional mensurational measurements such as forest area, tree species, diameter, and survival and a suite of non-tree measurements related to the health of the forest. FIA data are recognized for their completeness, geographic coverage, and accessibility to users via a user-friendly interface to a national database. Three examples for three different regions of the United States illustrate the relevance and utility of FIA data for environmental and ecological assessments in the context of the Montreal Process. Several conclusions may be drawn from the examples: (1) for the Southern region, the forest land base is stable, and growing stock volume is increasing; (2) for the Mid-Atlantic region, contributions to carbon accumulation are slightly greater than for storage, and storage increases from north to south; and (3) for the Central Hardwoods region, tree species richness increases from north to south and from west to east and is stable or slightly increasing.

Maine's forests 2008

The second annual inventory of Maines forests was completed in 2008 after more than 3,160 forested plots were measured. Forest land occupies almost 17.7 million acres, which represents 82 percent of the total land area of Maine. The dominant forest-type groups are maple/beech/yellow birch, spruce/fir, white/red/jack pine, and aspen/white birch. Statewide volume equals 25.5 billion ft3, resulting from nearly 590 million ft3 of live-tree volume grown each year. The report also contains additional information on sustainability, biomass, carbon, forest health, land-use change, and timber products. The DVD includes detailed information on forest inventory methods, quality of estimates found, and tables forest statistics.

Annual inventory report for Pennsylvania's forests: results from the first two years.

In 2000, the USDA Forest Services Forest Inventory and Analysis (FIA) program implemented a new system for inventory and monitoring Pennsylvania?s forest resources. The most salient benefit of the new inventory process will be a nearly threefold improvement in timeliness. This report summarizes the results of the first 2 years of annual inventory measurements. The area of forest land in Pennsylvania has remained stable since a previous inventory in 1989. The Keystone States forests continue to mature as larger trees and an increase in inventory volume were recorded. A separate study of tree seedlings revealed a general lack of regeneration in one-third to one-half of the stands in which regeneration should be adequate.

Pennsylvania's forest 2004.

Pennsylvanias forest-land base is stable, covering 16.6 million acres or 58 percent of the land area. Sawtimber volume totals 88.9 billion board feet, an average of about 5,000 board feet per acre. Currently, only half of the forest land that should have advance tree seedling and sapling regeneration is adequately stocked with high-canopy species, and only one-third has adequate regeneration for commercially desirable timber species. Several exotic diseases and insects threaten the health of Pennsylvanias forests. Stressors such as drought, acidic deposition, and ground-level ozone pollution are adversely affecting the States forests.

Forest Resources and Conditions

The forests of the northern United States support a rich mix of floral and faunal communities that provide inestimable benefits to society. Today’s forests face a range of biotic and abiotic Stressors, not the least of which may be environmental change. This chapter reviews the compositional traits of presettlement forests and traces the major land use patterns that led to the development of contemporary forested ecosystems. Human impacts have dominated forest development over the last 150 years, so considerable attention is paid to current compositional, structural, and successional traits resulting from these impacts. Estimates of forest carbon storage set the stage for later chapters dealing with environmental factors affecting forest health and resiliency. Resource sustainability is addressed by examining productive capacity (growth) in relation to forest drain components: mortality and removals. Historical information has been gleaned from the literature. Source material for recent trends in timberland area, species composition, stand structure, and net forest drain is from the successive state-level forest inventories conducted by the United States Department of Agriculture (USDA) Forest Service’s Forest Inventory and Analysis (FIA) unit. Much of this information was compiled from the FIA’s Eastwide Database (Hansen et al., 1992).

Massachusetts' forest resources, 2012

This publication provides an overview of forest resource attributes for Massachusetts based on an annual inventory conducted by the Forest Inventory and Analysis (FIA) program at the Northern Research Station of the U.S. Forest Service. These estimates, along with web-posted core tables, will be updated annually. For more information please refer to page 3 of this report.

West Virginia Forests 2013

The annual inventory of West Virginias forests, completed in 2013, covers nearly 12.2 million acres of forest land with an average volume of more than 2,300 cubic feet per acre. This report is based data collected from 2,808 plots located across the State. Forest land is dominated by the oak/hickory forest-type group, which occupies 74 percent of total forest land area. Seventy-eight percent of forest land area consists of a plurality of large diameter trees, 15 percent contains medium diameter trees, and 7 percent contains small diameter trees. The volume of growing stock on timberland has been rising since the 1950s and currently totals over 25 billion cubic feet. The average annual net growth of growing-stock trees on timberland from 2008 to 2013 is approximately 519 million cubic feet per year. Important species compositional changes include increases in sapling numbers of yellow-poplar, American beech, and noncommercial species, which coincide with decreases in numbers of trees and saplings of oak species. Additional information is presented on forest attributes, land use change, carbon, timber products, species composition, regeneration, and forest health. Detailed information on forest inventory methods, data quality estimates, and summary tables of population estimates, are available at http://dx.doi.org/10.2737/NRS-RB-105.