Invasive species exact important ecologic, economic, and cultural tolls in forests. This research focused on the intersections of invasive ecology, forest management, and a forest commodity. Invasive ecology was explored through an assessment of two potential biological control agents of hemlock woolly adelgid. The two species of silver fly (Leucopis spp.) from the Pacific Northwest were first examined for temporal resource partitioning patterns. The niches of these species were then examined spatially by developing a species distribution model. Leucopis spp. exhibited sinusoidal patterns of daily emergence when examined over a 29-day period, with peak daily abundances that were inversely related. Spatially, however, landscape-scale and climatic indicators were not significant in predicting the presence of Leucopis spp. in the Pacific Northwest. This adds important information about niche dynamics of Leucopis spp. in the Pacific Northwest, which may have logistical and operational implications for their use in the USDA Forest Service’s Hemlock Woolly Adelgid Initiative. Additionally, the potential opportunities and risks of using wood that has been impacted by invasive species and pests was explored through a literature analysis focused on three species posing a threat to northeastern US forests: emerald ash borer, hemlock woolly adelgid, and southern pine beetle. Based on this review, I concluded that although opportunities for the use of this wood are sometimes recognized, the phytosanitary risks in feedstock pre-treatment are not being directly addressed in US-related literature. These studies provide important evidence for adaptive solutions to forest pests that consider both forest health and forest economics.

The insecticide imidacloprid, has been found to be highly effective in suppressing hemlock woolly adelgid, Adelges tsugae. Laricobius nigrinus is a predatory beetle released as a biological control of adelgids in the eastern U.S. This project was designed to develop a pest management strategy that utilizes both tactics concurrently within the same site. It will assess the efficiency of this strategy in reducing HWA populations and improving the health of hemlock forests. The project was started in 2010 and data were collected annually through 2016. The project spanned three sites in three different states (KY, WV, and TN). Results show that tree health has generally declined across all sites for each year. HWA population index values are highly variable and are more strongly influenced by the occurrence of low winter temperatures than by treatment effect. Cross-correlation analysis of tree health and HWA population, revealed characteristics of their temporal relationship. In two of the three sites, tree health lagged up to three years behind changes in HWA population, and HWA populations lagged approximately one year behind changes in tree health. L. nigrinus did not establish at any site as of 2016. The lack of sustained recovery of the beetle may be attributable to the occurrence of extremely cold temperatures during the winters of 2014 and 2015 which produced subsequent crashes in the HWA population at two of the three sites. In TN, the L. nigrinus population may have never established due to a decline in the HWA population shortly after release. / Master of Science in Life Sciences

Environmental quality is a construct that has currency at the interface between science and policy—it is used both to describe current conditions as well as prescribe desired future conditions. However, environmental quality has a multiplicity of definitions, owing to: a) the fact that there are a number of terms (or "sub constructs") taken to be synonymous with environmental quality (i.e. environmental health, sustainability, biodiversity, integrity, and the like), and b) the fact that each of these sub constructs, in turn, have multiple meanings. Many in the field of natural sciences have been working on this problem of ambiguity—attempting to develop precise and powerful definitions. Still others argue that environmental quality is a concept open to societal negotiation (in addition to scientific discovery). In this thesis, I argue that environmental quality can be understood and discussed by examining understandings of Nature and evaluations for Nature that seem to contribute to the ambiguity of meanings and outcomes for environmental quality. To reach these conclusions, I interviewed 24 stakeholders who represented a broad range of concerns about and interests in environmental quality on private forest land in Southwest Virginia. I reviewed nearly 300 pages of interview text, looking for emerging themes and structures from their hour-long (on average) discussions of environmental quality. I found that among these 24 stakeholders, there were indeed, many ways of defining environmental quality (i.e. health, biodiversity, site productivity, et cetera). Additionally, I found that these different definitions for environmental quality seem to correlate with different understandings of Nature (what is Nature like?) and different values for Nature (how should Nature be used?) I conclude by discussing these implications, using examples from forestry outreach and extension. / Master of Science

This paper looks at the intersections of nature and culture through a study of forest ecosystem restoration efforts in the Ouachita National Forest (Arkansas and Oklahoma). Ecosystem restoration goals are often informed by a pre-European settlement (PES) condition, with an implicit (and occasionally explicit) assertion that such conditions are both more natural than and preferable to the contemporary state. In many cases resuming pre-suppression fire regimes remains a key mechanism for achieving this restored condition. This study’s three main objectives include: (1) determining how PES benchmarks arose in restoration thought, (2) examining how the choice to use a PES benchmark is influenced by culture, and (3) evaluating the pragmatism of including a PES benchmark in restoration projects. The issues of the naturalness of PES conditions, along with the cultural implications of adopting a PES benchmark, are critically examined against the backdrop of historic legacies of fire suppression and paleoecological change. Normative balance-of-nature ideas are discussed in light of their influence on natural resource management paradigms. Linkages are drawn between PES conditions and forest health. Evidence supporting the ecological resilience associated with PES vegetation communities is considered alongside the anticipation of future forcing factors. The idea that restored forests represent an ecological archetype is addressed. Finally, an alternative explanation concerning the tendency of ecosystem restoration efforts to converge on a single historic reference condition – a point of equifinality – is weighed against notions of: (1) anthropic degradation, (2) a regional optimum, and (3) a socially-constructed yearning for a frontier ideal. Because of the unique convergence between historical human activities and natural processes, contemporary culture has conceived of the PES time period as a sort of frontier ideal. The creation of PES benchmarks appears to be an unintentional consequence of attempts to restore forest health rigorously defined by biometric standards. This study offers, to restoration thinking, a framework for critically evaluating the inclusion of historic reference conditions and a means of responding to criticism surrounding their use. This study's findings rest on evidence gathered from paleoecological and historical biogeography data, interviews, archival materials, cultural landscape interpretation, landscape and nature-based art, and complexity theory.

Light detection and ranging (LiDAR) data can provide detailed information about three-dimensional forest horizontal and vertical structure that is important to forest productivity and wildlife habitat. Indeed, LiDAR data have been shown to provide accurate estimates to forest structural parameters and measures of higher trophic levels (e.g., avian abundance and diversity). However, links between forest structure and tree function have not been evaluated using LiDAR. This study was designed and scaled to assess the relationship of LiDAR to multiple aspects of forest structure and higher trophic levels (arthropod and bird populations), which included the ground-based collection of percent crown and understory closure, as well as arthropod and avian abundance and diversity data. Additional plot-based measures were added to assess the relationship of LiDAR to forest health and productivity. High-resolution discrete-return LiDAR data (flown summer of 2009) were acquired for the Hubbard Brook Experimental Forest (HBEF) in New Hampshire, USA. LiDAR data were classified into four canopy structural categories: 1) high crown and high understory closure, 2) high crown and low understory closure, 3) low crown and high understory closure, and 4) low crown and low understory closure. Nearby plots from each of the four LiDAR categories were grouped into "blocks" to assess the spatial consistency of data. Ground-based measures of forest canopy structure, site, stand and individual tree measures were collected on nine 50 m-plots from each LiDAR category (36 plots total), during summer of 2012. Analysis of variance was used to assess the relationships between LiDAR and a suite of tree function measures. Our results show the novel ability of LiDAR to assess forest health and productivity at the stand and individual tree level. We found significant correspondence between LiDAR categories and our ground-based measures of tree function, including xylem increment growth, foliar nutrition, crown health, and stand mortality. Furthermore, we found consistent reductions in xylem increment growth, decreases in foliar nutrition and crown health, and increases in stand mortality related to high understory closure. This suggests that LiDAR measures can reflect competitive interactions, not just among overstory trees for light, but also interactions between overstory trees and understory vegetation for resources other than light (e.g., nutrients). High-resolution LiDAR data show promise in the assessment of forest health and productivity related to tree function.

Assessment of forest damage using satellite and lidar data Abstract The main objective of this thesis is to create a methodical procedure used for the evaluation of forest damage in the chosen area of the National Park Sumava, Czech Republic. In this work were combined the multispectral satellite data and data of airborne laser scanning. The forests in this area are heavily damaged mainly due to bark beetle outbreak. You can find here as healthy so damaged forests. Based on this methodology will be differentiated greater number of classes than I found in the literature. In this work was used pansharpened multispectral image SPOT, multispectral image Landsat and airborne laser scanning data with low density points. Another task was to get height information from ALS data in the form of grid. Forest stands were classified using object-oriented classification, which included at first segmentation and then creation of classification base. In classification entered spectral information and height information obtained from the ALS data. Forests were classified into 5 classes and accuracy of both classifications was evaluated using the error matrix and kappa coefficient. SPOT image classification reached kappa coefficient of 68,5 % and Landsat image classification reached kappa coefficient of 72,3 %. From the...

Thesis (Ph. D.)--North Carolina State University, 2004. / Title from PDF title page (viewed Mar. 27, 2005). Includes vita. Includes bibliographical references.

Widespread mortality of quaking aspen (Populus tremuloides Michx.) has occurred over large expanses of the Western US during the 20th century. While much of this decline was due to conifer encroachment into seral aspen, significant aspen losses also occurred in areas of persistent aspen and may have been exasperated by drought conditions. Aspen decline has been especially notable at Cedar Mountain, Utah, an area of mostly private land and extensive persistent aspen coverage. The objectives of this study were to create a time series of live and dead aspen cover on the Cedar Mountain landscape, using remotely sensed imagery, and to test whether water stress correlated to the decline therein. To accomplish these objectives, a decision tree classifier was used to classify the Cedar Mountain area into live and dead aspen cover classes for the years 1985, 1990, 1995, 2001, 2005, and 2008. Thereafter, post-classification change analysis was performed to determine areas and time periods of elevated decline. Regression analyses were performed to ascertain correlations between climatic data and percent change in aspen cover. A topographic analysis using zonal statistics was also performed to determine landscape positions where aspen decline is more prevalent. The time series models indicated that aspen decline followed a step-wise pattern with an overall decrease of 23.57 % in aspen cover during a 23-year period. Considerable aspen decline occurred early in the study time frame, with decreases of 1.38 and 1.36 -1 in 1990 and 1995, respectively. The middle period between 1995 and 2001 had no net change in aspen cover. However, the end of the time series showed the greatest decline with decreases of 1.56 and 1.99 % yr-1 in 2005 and 2008, respectively. There was a correlation between percent change in aspen cover and precipitation, suggesting that drought weakens aspen, making it susceptible to future decline. The topographic zonal statistics revealed that drier landscape positions had greater frequencies of dead aspen. The most significant predictor of aspen decline was elevation, which was significantly greater in the live aspen for three of the five years.

Global climate change is predicted to affect environmental systems at the midlatitudes, but the scope, severity, and outcomes of these impacts are yet to be fully understood. This study focuses on the implications of short-term climate variability for forests in central Kentucky. Using a Normalized Difference Vegetation Index (NDVI) calculated from MODerate-Resolution Imaging Spectroradiometer (MODIS) instrument data, the photosynthetic activity of vegetation at Mammoth Cave National Park (MACA) is tracked from 2000 to 2013. Three methods were employed to examine the changes and climate influences in vegetation over the study period: 1) aggregating the NDVI of the Park by year and by summer months (June, July, and August) and examining how these productivity trends could be influenced by precipitation and temperature fluctuations, 2) examining the trend of the NDVI at selected dates throughout the study period to detect phenological shifts around leaf-out and leaf-off, and 3) using a generalized vegetation classification of MACA to clip the imagery based on areas of similar vegetation and then testing correlations between those subsets and teleconnections. The results from the aggregated NDVI show there is an insignificant negative trend. A negative relationship between summer forest productivity at MACA and temperature was found, though more data are needed to rigorously validate this result. Changes in phenology indicate forest productivity is decreasing earlier each year throughout the study period. Finally, the Multivariate ENSO Index and the Pacific Decadal Oscillation index are shown to have significant positive correlations with the summer productivity of MACA during the study period.

Thaumastocoris peregrinus (T. peregrinus) is a sap-sucking insect that feeds on Eucalyptus leaves. It poses a major threat to the forest sector by reducing the photosynthetic ability of the tree, resulting in stunted growth and even death of severely infested trees. The foliage of the tree infested with T. peregrinus turns into a deep red-brown colour starting at the northern side of the canopy but progressively spreads to the entire canopy. The monitoring of T. peregrinus and the effect it has on plantation health is essential to ensure productivity and future sustainability of forest yields. Insitu hyperspectral remote sensing combined with greater availability and lower cost of new generation multispectral satellite data, provides opportunities to detect and map T. peregrinus damage in plantation forests. This research advocates the development of remote sensing techniques to accurately detect and map T. peregrinus damage, an assessment that is critically needed to monitor plantation health in South Africa. The study first provides an overview of how improvements in multispectral and hyperspectral technology can be used to detect and map T. peregrinus damage, based on the previous work done on the remote sensing of forest pests. Secondly, the utility of field hyperspectral remote sensing in predicting T. peregrinus damage was tested. High resolution field spectral data that was resampled to the Hyperion sensor successfully predicted T. peregrinus damage with high accuracies using narrowband normalized indices and vegetation indices. Field spectroscopy was further tested in predicting water stress induced by T. peregrinus infestation, in order to identify early physiological stages of damage. A neural network algorithm successfully predicted plant water content and equivalent water thickness in T. peregrinus infested plantations. The result is promising for forest health monitoring programmes in detecting previsual physiological stages of damage. The analysis was then upscaled from field hyperspectral sensing to spaceborne sensing using the new generation WorldView-2 multispectral sensor, which contains key vegetation wavelengths. Partial least squares regression models were developed from the WorldView-2 bands and indices and significant predictors were identified by variable importance scores. The red edge and near-infrared bands of the WorldView-2 sensor, together with pigment specific indices predicted and mapped T. peregrinus damage with high accuracies. The study further combined environmental variables and vegetation indices calculated from the WorldView-2 imagery to improve the prediction and mapping of T. peregrinus damage using a multiple stepwise regression approach. The regression model selected the near infrared band 8 of the WorldView-2 sensor and the temperature dataset to predict and map T. peregrinus damage with high accuracies on an independent test dataset. This research contributes to the field of knowledge by developing innovative remote sensing techniques that can accurately detect and map T. peregrinus damage using the new generation WorldView-2 sensor. The result is significant for forest health monitoring and highlights the importance of improved sensors which contain key vegetation wavelengths for plantation health assessments. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.