Kurt W. Gottschalk

Prescribing regeneration treatments for mixed-oak forests in the Mid-Atlantic region

Includes guidelines for using the SILVAH decision-support system to perpetuate oak forests in the Mid-Atlantic region. Six chapters provide information on values of oak forests, inventory methods, key decision variables, decision charts, and silvicultural prescriptions, as well as guidance on fostering young stands. Sample tally sheets and SILVAH computer printouts are included in the Appendix.

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.

Aspect Induced Differences in Vegetation, Soil, and Microclimatic Characteristics of an Appalachian Watershed

Abstract This study evaluates and quantifies the variation in vegetation, plant nutrients, and microclimate across four topographic aspects in an Appalachian watershed (39°39′43′′N, 79°45′28′′W). The study found that the north and east aspects were 27–50% more productive than the west and southwest aspects. Species groups that showed strong aspect preference included yellow poplar (Liriodendron tulipifera), black cherry (Prunus serotina), chestnut oak (Quercus prinus), and white oak (Quercus alba); the former two being dominant on the north and east aspects while the latter two dominate the west and southwest aspects. Red oak (Quercus rubra) and red maple (Acer rubrum) showed mild aspect preference indicating their broad ecological amplitude. Although the north and east aspects had greater biomass, the west and southwest aspects had about 23% more stems per hectare. There were large differences in microclimate among the four aspects. Air temperature during midday period averaged 25.2°C, 24.9°C, 30.5°C, and 29.4°C for the north, east, west and southwest aspects respectively. The maximum temperature difference between the mesic (north and east aspects) and xeric (west and southwest aspects) sites was 5.55°C and was observed at noon. The relative humidity at the xeric site was about 25% lower than that at the mesic site during midday periods. Plant water stress as measured by vapor pressure difference was about 37% higher on west and southwest aspects than on north and east aspects. Plant nutrients only showed minor differences with concentrations being higher on the north and east aspects except for phosphorus, which was higher on the west and southwest aspects.

Within-population variation in response of red oak seedlings to herbivory by gypsy moth larvae

The potential for an evolutionary response to gypsy moth (Lymantna dispar L.) herbivory was investigated in red oak (Quercus rubra L.), a preferred host. Seedlings of nine open-pollinated families were grown in a greenhouse and experimentally defoliated by fourth instar larvae in the summer of 1991 to assay for intraspecific variation in resistance to and recovery from herbivory. Defoliation increased mortality and reduced growth differentially among the nine families. Family differences in plant size before defoliation explained much of the variation in mortality and growth following defoliation. Different allocation patterns among families explained some of the variation in seedling growth. Absolute growth rate of larvae was significantly different among families and higher on individuals with larger leaf area, but resistance to defoliation and larval growth efficiency were not significantly different among families. Since we have not measured the additive genetic variation in seedling traits, the magnitude of the potential evolutionary response cannot be projected from this study, but intraspecific variability in red oak does exist for tolerance and response to defoliation and possibly for resource allocation. Phenotypic selection on traits related to response to defoliation may result in evolutionary change in natural populations of red oak.

Do chestnut, northern red, and white oak germinant seedlings respond similarly to light treatments? Growth and biomass

Northern red oak (Quercus rubra L.) seedling growth has been extensively studied. White oak (Quercus alba L.) and chestnut oak (Quercus prinus L.), however, are far less investigated despite their importance among upland oak species in eastern North American forests. We characterized white and chestnut oak seedling response to light and available soil nutrients while using northern red oak as a benchmark. Germinants were grown within one of three shade treatments (25%, 18%, and 6% of full sun) in one of two native forest soil mixes over two growing seasons. Leaf area, shoot mass, and root mass of all three species showed positive growth responses to increasing light. Growth and biomass were higher for all species grown in the more nutrient-rich forest soil, but chestnut oak displayed the greatest positive responses to the higher nutrient levels. White oak seedlings were the slowest growers and demonstrated the most root-centered growth, with root to shoot ratios almost twice that of either chestnut or nor...

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.

Restoration of three forest herbs in the Liliaceae family by manipulating deer herbivory and overstorey and understorey vegetation

Background: Research on herbaceous vegetation restoration in forests characterised by overstorey tree harvests, excessive deer herbivory, and a dominant fern understorey is lacking. Most of the plant diversity found in Eastern hardwood forests in the United States is found in the herbaceous understorey layer. Loss of forest herbaceous species is an indicator of declining forest conditions. Aims: The combined effects of deer herbivory, competitive understorey vegetation removal, and overstorey tree removal on the abundance and reproductive capacity of three understorey herbs in the Liliaceae family were evaluated. Methods: A split-plot randomised block design was used with three replicates. Treatments included three harvest intensities, fenced/unfenced, herbicide/no herbicide-treated, prescribed burn/no prescribed burn, and all combinations. A generalised linear model was used to compare treatment effects over 8 years. Results: Both fruit production and cover increased significantly in fenced areas for all three species. There was a significant 6-year recovery period for cover of the three species in response to herbicide. There was a significant 4-year recovery period of fire-treated plots for fruit production of the three species. The most intensively cut, fenced, and herbicide-treated plots had the greatest increases in sapling and Rubus spp. cover. Cover and fruit production of the three herbs were significantly greatest in the moderate-cut treatment. Conclusions: Restoration of these three liliaceous species is most likely to occur in Eastern deciduous forests and similar forests using a combined fenced and moderate-cut treatment.

Special feature: alien pests threatening biodiversity of forest ecosystems

Throughout the world, biological invasions have become one of the most important factors threatening biodiversity. Many species are introduced into ‘‘a new world’’ accidentally or intentionally. Most fail to become established, but some become established, colonize, and start to increase and expand their ranges. Some invasive pathogens damage and kill host species. Some invasive herbivores destroy vegetation by feeding and killing host plants. Some invasive carnivores extinguish their prey by depressing their density below the minimum viable population. Some domestic species are replaced by or hybridize with invasive species in a similar niche. The effects of invasive species are more than these direct effects. They cause cascading changes in the ecology, function, and value of diverse ecosystems. In forest ecosystems, there are four major forest diseases that are not epidemic in their original places but are epidemic in ‘‘new worlds’’: chestnut blight and pine rust disease both in North America, Dutch elm disease in North America and Europe, and pine wilt diseases caused by pinewood nematode in Asia and Europe. Regarding insect pests, the gypsy moth, the Asian long-horned beetle, and the emerald ash borer were all introduced to North America, established a population, and now cause serious damage to forest ecosystems there. Problems of invasive species to forest ecosystems will probably be more serious in the future. Probability of new invasions by alien species will increase greatly because of globalization. Future global warming will also accelerate the invasive species problems through pathways as follows: warm temperature will increase the number of combinations of invasive species and their hosts and host trees will be stressed by higher temperature than their original suitable temperature and increased droughts. During the 22nd World Congress of IUFRO, Brisbane, Australia, 8–13 August 2005, we organized a session titiled ‘‘Alien pests threatening biodiversity of forest ecosystems’’. The aim of the session was to cover the state of the art on invasive pest impacts to biodiversity of forest ecosystems. The session thus started with two general review presentations about forest pest invasions and biodiversity of forest ecosystems. Andrew Liebhold (USDA Forest Service, USA) summarized the influence of alien pest species in forest succession. Nod Kay (NZFRI, New Zealand) discussed the role of biodiversity in explaining patterns of establishment and host range expansion. Three presentations then followed, covering invasive pests of different taxa. Fumio Yamada (FFPRI, Japan) described the impacts of invasive mongoose on native animals in Amami-Island, Japan and provided a good example of an island ecosystem vulnerable to invasive species. Anna Schoettle (USDA Forest Service, USA) discussed the long term consequences of the alien disease, white pine blister rust, on ecosystem biodiversity and sustainability in North America. Glenn Stewart (Lincoln University, New Zealand) described vertebrate invasions and their effects on biodiversity of New Zealand forests. He demonstrated that native vegetation had been severely impacted by introduced mammals, but the degree, to which natural processes are being impaired was highly variable. Seventeen poster N. Kamata (&) The University of Tokyo, University Forests, 1-1-1 Yayoi, Bunkyo, Tokyo 113-8657, Japan e-mail: kamatan@uf.a.u-tokyo.ac.jp

Regional patterns of declining butternut (Juglans cinerea L.) suggest site characteristics for restoration

Abstract Butternut trees dying from a canker disease were first reported in southwestern Wisconsin in 1967. Since then, the disease has caused extensive mortality of butternut throughout its North American range. The objectives of this study were to quantify changes in butternut populations and density across its range and identify habitat characteristics of sites where butternut is surviving in order to locate regions for potential butternut restoration. The natural range of butternut (Juglans cinerea L.) extends over a large region of eastern N. America encompassing New Brunswick south to North Carolina, north to Minnesota, and southwest to Missouri. Despite the species’ large range, it is typically not a common tree, comprising a relatively minor component of several different forest types. We evaluated change in butternut abundance and volume from current and historic data from 21 states in the eastern United States. We related abundance and volume at two time periods to a suite of ecological and site factors in order to characterize site conditions where butternut survived. We also assessed the current level of butternut mortality across its range. Since the 1980s, the number of butternut trees and butternut volume have decreased by 58% and 44%, respectively, across its US range. Substantial relative decreases in tree numbers and volume occurred in most ecoregion sections. Five environmental variables were found to be significant predictors of butternut presence. The potential impacts of butternut canker are particularly acute as the canker pathogen invasion pushes a rare tree species toward extinction, at least at a local scale. Based on the results presented here, large‐diameter maple/beech/birch stands in dry, upland sites in eastern Minnesota, western Wisconsin, and upstate New York appear to offer the most favorable conditions for butternut growth and survival and thus may be the best stands for planting resistant butternut trees.