Randall S. Morin

Mapping host-species abundance of three major exotic forest pests

Periodically over the last century, forests of the Eastern United States devastated by invasive pests. We used existing data to predict the geographical extent of future damage from beech bark disease (BBD), hemlock woolly adelgid (HWA), and gypsy moth. The distributions of host species of these alien pests were mapped in 1-km2 cells by interpolating host basal area/ha from 93,611 forest-inventory plots in 37 states. The interpolated surfaces were adjusted for forest density (percent land cover) by multiplying values by an estimate of percent forest cover derived from existing land-cover maps (30-m2 cells). According to our estimates, BBD currently occupies only about 27 percent of its potential range in land area, but has invaded more than 54 percent in total host density. HWA occupies nearly 26 percent of its potential range in land area, and about one-quarter in total host density. Gypsy moth occupies only 23 percent of its potential range in the Eastern United States, and only 26 percent in total host density.

Anisotropic spread of hemlock woolly adelgid in the eastern United States

Simple population models predict that the spread of an invading species through a homogenous habitat should be equal in all directions, but geographic variation in the habitat that affects either reproduction or movement could result in variable rates of spread. We analyse records of the historical range expansion of the hemlock woolly adelgid (HWA) (Adelges tsugae Annand) in the eastern United States from 1951 to 2006 to document that this species has spread in an anisotropic fashion. Furthermore, the magnitude and direction of this anisotropy has varied through time. We explore the extent to which this spatial and temporal variation in spread can be explained by geographical variation in climate and by the abundance of hosts, eastern hemlock (Tsuga canadensis L.) and Carolina hemlock (Tsuga caroliniana Engelm.). We found that a significant component of the spatial anisotropy in HWA spread rate can be explained by the geographical distribution of host trees. January temperatures were negatively associated with spread rates but this may be an artifact of the association between hemlock and cold climates. The current distribution of the adelgid in eastern N. America may be approaching the extent of its potential range to the south and west determined by availability of host hemlock and to the north determined by lethal cold winter temperatures.

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.

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.

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.

Analysis of forest health monitoring surveys on the Allegheny National Forest (1998-2001)

Describes forest vegetation and health conditions on the Allegheny National Forest (ANF). During the past 20 years, the ANF has experienced four severe droughts, several outbreaks of exotic and native insect defoliators, and the effects of other disturbance agents. An increase in tree mortality has raised concerns about forest health. Historical aerial surveys (1984-98), Forest Inventory and Analysis plot data collected in 1989, and FHM plot data collected 1998-2001 were analyzed to compare disturbed and undisturbed areas. Tree mortality and crown dieback levels were compared between undefoliated areas and areas defoliated by cherry scallopshell moth, elm spanworm, and gypsy moth. American beech mortality was compared inside and outside the beech bark disease killing front. This study illustrates the value of an intensified grid of P3 plots and demonstrates the integration of aerial survey and plot data.

The Forests of Southern New England, 2007: A report on the forest resources of Connecticut, Massachusetts, and Rhode Island

This report summarizes the results of the fifth forest inventory of the forests of Southern New England, defined as Connecticut, Massachusetts, and Rhode Island, conducted by the U.S. Forest Service, Forest Inventory and analysis program. Information on forest attributes, ownership, land use change, carbon, timber products, forest health, and statistics and quality assurance of data collection are included. There are 5.1 million acres of forest land across the region; 60 percent of this forest land is in Massachusetts, 33 percent in Connecticut, and 7 percent in Rhode Island. This amount has decreased by 5 percent since the last inventory was completed in 1998. There are 2.6 billion trees on this forest land that have total volume of 12.6 billion cubic feet. Red maple and eastern white pine are the most common species in terms of both numbers of trees and volume. Fifty percent of the forest land is classified as the oak-hickory forest type.

Wisconsin's forests, 2004

The first full, annualized inventory of Wisconsins forests was completed in 2004 after 6,478 forested plots were visited. There are more than 16.0 million acres of forest land in the Wisconsin, nearly half of the States land area; 15.8 million acres meet the definition of timberland. The total area of both forest land and timberland continues an upward trend that began in the 1960s. Red maple, sugar maple, and quaking aspen are the most common trees with diameters at breast height greater than 5 inches; there are 298, 250, and 244 million trees of these species, respectively. Aspen is the most common forest type, followed by sugar maple/beech/yellow birch, and white oak/red oak/hickory. This report includes detailed information on forest attributes and health and on agents of change such as the introduction of nonnative plants, insects, and diseases and changing land-use patterns.

Mortality rates associated with crown health for eastern forest tree species

The condition of tree crowns is an important indicator of tree and forest health. Crown conditions have been evaluated during inventories of the US Forest Service Forest Inventory and Analysis (FIA) program since 1999. In this study, remeasured data from 55,013 trees on 2616 FIA plots in the eastern USA were used to assess the probability of survival among various tree species using the suite of FIA crown condition variables. Logistic regression procedures were employed to develop models for predicting tree survival. Results of the regression analyses indicated that crown dieback was the most important crown condition variable for predicting tree survival for all species combined and for many of the 15 individual species in the study. The logistic models were generally successful in representing recent tree mortality responses to multiyear infestations of beech bark disease and hemlock woolly adelgid. Although our models are only applicable to trees growing in a forest setting, the utility of models that predict impending tree mortality goes beyond forest inventory or traditional forestry growth and yield models and includes any application where managers need to assess tree health or predict tree mortality including urban forest, recreation, wildlife, and pest management.

West Virginia's Forests 2008

The first full annual inventory of West Virginias forests reports 12.0 million acres of forest land or 78 percent of the States land area. The area of forest land has changed little since 2000. Of this land, 7.2 million acres (60 percent) are held by family forest owners. The current growing-stock inventory is 25 billion cubic feet--12 percent more than in 2000--and averages 2,136 cubic feet per acre. Yellow-poplar continues to lead in volume followed by white and chestnut oaks. Since 2000, the saw log portion of growing-stock volume has increased by 23 percent to 88 billion board feet. In the latest inventory, net growth exceeded removals for all major species. Detailed information on forest inventory methods and data quality estimates is included in a DVD at the back of this report. Tables of population estimates and a glossary are also included.