Forest Sciences Commons^™

Predicting Leucotaraxis Spp. Adult Emergence In The Pacific Northwest With Implications For Biological Control Of Hemlock Woolly Adelgid In The Eastern United States, Liam Farley

Graduate College Dissertations and Theses

Hemlock woolly adelgid (Adelges tsugae) is a non-native, invasive pest of eastern hemlock (Tsugae canadensis) and Carolina hemlock (Tsugae caroliniana), both of which are considered important foundation species in forest ecosystems. Adelges tsugae has caused widespread decline and mortality of hemlock trees in eastern North America. Native hemlocks are particularly vulnerable because of the absence of co-evolved plant defenses and lack of natural enemies of A. tsugae. Managing A. tsugae through development of a biological control program has great potential at the regional level. Two species of silver fly from the Pacific northwest (PNW) Leucotaraxis argenticollis and Leucotaraxis piniperda are …

Forest Management In The Context Of Global Change: Impacts Of Disturbance, Adaptive Management, And Invasive Species On Northeastern Forests, Jennifer Santoro

Graduate College Dissertations and Theses

Climate change is predicted to have variable and uncertain effects on forested ecosystems globally. In the northeastern US, natural disturbances have historically been a central driver of forest successional dynamics, but as climate warming is projected to alter the frequency and severity of these events, post-disturbance management strategies to sustain biodiversity and ecosystem services must adaptively change to promote forest resilience. A suite of adaptive silvicultural actions has been proposed to promote forest resilience in the face of uncertainty, but due to the multi-decadal scale of forest management, initial field experiments are only beginning to show results. To address these …

Reorienting Local Housing Development Trends Via Land Value Taxation: A Bottom-Up And Top-Down Quantitative Analysis, Dakota B. Walker

Graduate College Dissertations and Theses

The region surrounding Burlington, Vermont is in the midst of sparse, decentralized growth which threatens the sense of place from which it has thrived. Many have argued that such development tendencies result from a disconnect between land use incentives at the individual level and the fruits of compact settlement, which materialize at larger scales. Two overarching problems are understood to contribute to this disconnect; the ability to privately appropriate the collectively-created value of land, and the inability to recognize ecological opportunity costs of natural land conversion in land use decisions. One proposed solution is the Land Value Tax (LVT). By …

Short- And Long-Term Impacts Of Forest Management In Response To The Invasive Emerald Ash Borer In New England Forests, Hanusia Higgins

Graduate College Dissertations and Theses

As non-native forest pests disperse across the United States, the emerald ash borer, Agrilus planipennis (EAB), has emerged as one of the most costly and destructive invaders. In response to EAB, forest management practices, including pre-salvage logging, "phloem reduction" (large ash removal), and strategies to improve future ash regeneration, have been implemented to meet economic, ecological, cultural, and safety objectives. Although many studies have quantified the impacts of EAB on mortality of ash trees (Fraxinus spp.), less is known about the short- and long-term ecological impacts of forest management in response to this pest. In summer 2020, we measured forest …

Climate Adaptive Forest Management In The Northeastern Us: Social And Ecological Motivations, Barriers, And Responses Of Rural And Urban Foresters, Teresa Mcgann

Graduate College Dissertations and Theses

This project examines how foresters in a diversity of professional contexts perceive and respond to global change in the northeastern United States, with the goal of supporting foresters in broadening and deepening their use of climate adaptive strategies. Based on qualitative analysis of 32 in-depth semi-structured interviews with urban and rural foresters (n = 15 and n = 17, respectively) across New England and New York, a summary is presented of the i) important environmental drivers of adaptation; ii) commonly employed adaptive practices; iii) significant barriers to adaptation; and iv) approaches to working through named barriers. According to the motivations, …

Drivers And Controls On Soil Carbon Storage In Temperate Forest Soils, Adam Noel

Graduate College Dissertations and Theses

Elevated atmospheric CO2 levels pose a threat the global climate stability but large amounts of carbon can be held within soils worldwide. Forests function to capture carbon and eventually, through litter inputs and decomposition, add this carbon to soil systems. This process is driven by climate, landscape conditions, forest and soil characteristics, that have complex interactions with one another across spatial scales. In this dissertation, I examine drivers of carbon contributions to the mineral soil, via litter decomposition and forest floor carbon pools, and how these contributions vary with forest composition and soil conditions. First, using data from a 10-year …

Forest Development And Regeneration Dynamics In The Context Of Global Change And Associated Adaptation Strategies, Peter Clark

Graduate College Dissertations and Theses

Over the past century, forested ecosystems in northeastern North America have undergone significant changes characterized by the recovery from intensive land use and impacts from the introduction of invasive insects and disease. These changes, coupled with emerging threats posed by a changing climate present challenges to the maintenance and conservation of biodiversity, ecological functions, and delivery of critical forest ecosystem services. While management strategies to increase forest resilience and mitigate impacts from climate change have been broadly proposed, there are nascent empirical evaluations of their effectiveness. To address this uncertainty, this dissertation couples field manipulations with long-term measurements to examine …

The Impacts Of Asian Longhorned Beetle On Forests In Southern New England, Olivia Fay Box

Graduate College Dissertations and Theses

Over the past several decades, the United States has been experiencing an influx of nonnative pests due to increased globalization, and many of these pests have the potential to permanently alter the composition, structure, and function of forests. Asian longhorned beetle (ALB) is an invasive pest that came into Worcester county, MA in 2008, where the first instance of this species invading both urban and natural forested areas was documented. Within the quarantine area for this novel invasion, 30,000 trees were removed over the course of 10 years as part of management efforts focused on harvesting all host species, primarily …

Informing Adaptation Strategies For Northeastern Pitch Pine Barrens In The Context Of Mesophication And Southern Pine Beetle Impacts, Elizabeth-Ann Jamison

Graduate College Dissertations and Theses

Forest pests, the most significant agent of disturbance in forested ecosystems of North America, are highly sensitive to climate change. Southern pine beetle (SPB) is a highly destructive pine forest pest that is expanding its historic range in the southeastern US to affect the globally rare northeastern pitch pine barrens as winter temperatures warm. By generating high levels of mortality in canopy pitch pine, SPB is accelerating the ongoing conversion of fire-dependent pine barrens to mesophilic forests. We aimed to support the adaptive management of pine barrens ecosystems in the context of these two threats by (1) assessing stand conditions …

Pacific Northwest To New England: Exploring The Intersections Of Invasive Ecology, Forest Management, And Alternative Energy, Alexandra N. Neidermeier

Graduate College Dissertations and Theses

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. …

Factors Affecting The Adoption Of Automated Wood Pellet Heating Systems In The Northeastern Us And Implications For The Transition To Renewable Energy, Laura Edling

Graduate College Dissertations and Theses

Public and private incentive programs have encouraged conversions to high efficiency, low emissions wood heating systems as a strategy to promote renewable energy and support local economies in the Northeastern US. Despite these efforts, the adoption of these systems remains slow. The study that is the subject of this dissertation examines several social, economic, policy and environmental factors that affect the decisions of individuals and small-scale institutions (local business and community facilities) to transition to automated wood pellet boilers and furnaces (AWPH) utilizing local fuel sources. Due to the complexity and risk associated with conversion, the transition to these systems …

Long-Term Dynamics And Silviculture Of Northern Hardwood Forests In The Northeast United States, Nicole Rogers

Graduate College Dissertations and Theses

Northern hardwood forests are a vast, temperate forest-type existing across much of northeastern North America. In the northeastern U.S., these forests are found from New York to Maine where they have central cultural, ecological, and economic significance. These ecosystems are incredibly variable across this region, growing on a range of sites and influenced by a suite of biotic and abiotic conditions. Developing management regimes that accommodate the ecological complexity of these forests has been the focus of silvicultural studies for decades; however, this work has been constrained by temporal and spatial limitations. As such, there is still uncertainty regarding the …

Future Forest Composition Under A Changing Climate And Adaptive Forest Management In Southeastern Vermont, Usa, Matthias Taylor Nevins

Graduate College Dissertations and Theses

Global environmental change represents one of the greatest challenges facing forest resource managers today. The uncertainty and variability of potential future impacts related to shifting climatic and disturbance regimes on forest systems has led resource managers to seek out alternative management approaches to sustain the long-term delivery of forest ecosystem services. To this end, forest managers have begun incorporating adaptation strategies into resource planning and are increasingly utilizing the outcomes of forest landscape simulation and climate envelope models to guide decisions regarding potential strategies to employ. These tools can be used alongside traditional methods to assist managers in understanding the …

Evaluating The Impacts Of Southern Pine Beetle On Pitch Pine Forest Dynamics In A Newly Invaded Region, Molly Heuss

Graduate College Dissertations and Theses

Southern pine beetle (SPB; Dendroctonus frontalis Zimmerman), a native insect that has historically affected pine ecosystems in the southeastern U.S., has recently expanded northward causing extensive tree mortality in pitch pine (Pinus rigida) and pitch pine-oak (Quercus spp.) forests across much of eastern Long Island, NY. Given the historic lack of SPB within these fire-dependent ecosystems, little is known regarding its impacts to forest composition, forest structure, or fuel loading. This study examined the short-term effects of SPB-induced tree mortality on the structure, composition, and fuel loading of pitch pine and pitch pine-oak communities to inform management recommendations and projections …

Remote Sensing Methods And Applications For Detecting Change In Forest Ecosystems, David James Gudex-Cross

Graduate College Dissertations and Theses

Forest ecosystems are being altered by climate change, invasive species, and additional stressors. Our ability to detect these changes and quantify their impacts relies on detailed data across spatial and temporal scales. This dissertation expands the ecological utility of long-term satellite imagery by developing high quality forest mapping products and examining spatiotemporal changes in tree species abundance and phenology across the northeastern United States (US; the ‘Northeast’).

Species/genus-level forest composition maps were developed by integrating field data and Landsat images to model abundance at a sub-pixel scale. These abundance maps were then used to 1) produce a more detailed, accurate …

Lasting Legacies Of Hurricane, Harvesting, And Salvage Logging Disturbance On Succession And Structural Development In An Old-Growth Tsuga Canadensis-Pinus Strobus Forest, Emma Sass

Graduate College Dissertations and Theses

Disturbance events affect forest composition and structure across a range of spatial and temporal scales, and forest development may differ after natural, anthropogenic, or compound disturbances. Following large, natural disturbances, salvage logging is a common yet controversial management practice around the globe. While the short-term impacts of salvage logging have been studied in many systems, the long-term effects remain unclear. Further, while natural disturbances create many persistent and unique microsite conditions, little is known about the long-term influence of microsites on forest development. We capitalized on over eighty years of data on stand development following the 1938 hurricane in New …

Regeneration Responses To Management For Old-Growth Characteristics In Northern Hardwood-Conifer Forests, Aviva Joy Gottesman

Graduate College Dissertations and Theses

Silviculture practices interact with multiple sources of variability to influence regeneration trends in northern hardwood forests. There is uncertainty whether low-intensity selection harvesting techniques will result in desirable tree regeneration. Our research is part of a long-term study that tests the hypothesis that a silvicultural approach called "structural complexity enhancement" (SCE) can promote accelerated development of late-successional forest structure and functions. Our objective is to understand the regeneration dynamics following three uneven-aged forestry treatments modified to increase postharvest structural retention: single-tree selection, group selection, and SCE. In terms of regeneration densities and composition, how do light availability, competition, seedbad, and …

Quantifying Tree Response To Alterations In Pollution Deposition And Climate Change In The Northeastern Us, Alexandra M. Kosiba

Graduate College Dissertations and Theses

Understanding tree physiological responses to climate change is critical for quantifying forest carbon, predicting species' range change, and forecasting growth trajectories. Continued increases in temperature could push trees into conditions to which they are ill adapted -- such as decreased depth of winter snow cover, altered water regimes, and a lengthened effective growing season. A complicating factor is that in the northeastern United States, climate change is occurring on a backdrop of acid deposition and land-use change. In this dissertation, I used three studies to investigate the spatiotemporal nuances of resultant tree and sapling physiology to environmental change.

First, I …

Social And Emotional Dimensions Of Succession Planning For Family Forest Owners In The Northeastern United States, Hallie E. Schwab

Graduate College Dissertations and Theses

Keeping forestland intact has emerged as a critical policy objective at state and federal levels. This target has been supported by substantial public investment. The collective impact from the bequest decisions of millions of landowning individuals and families has the potential to affect the extent and functionality of future forests in the United States. Despite a growing body of research devoted to studying these transitions in forest ownership, much remains unknown about how family forest owners make decisions in this arena. The social and emotional dimensions of woodland succession planning have been particularly under-examined. This thesis explores the process of …

Assessing The Efficacy Of Two Species Of Silver Fly, Leucopis Argenticollis And L. Piniperda, As Biological Control Agents Of Hemlock Woolly Adelgid, Adelges Tsugae, Kyle Motley

Graduate College Dissertations and Theses

Adelges tsugae Annand is a non-native invasive insect threatening the survival of eastern hemlock (Tsuga canadensis) and Carolina hemlock (T. caroliniana). A. tsugae is established in over half of the total range of eastern hemlock and the entire range of Carolina hemlock. Its continued spread, establishment and associated hemlock mortality make research into biological control of A. tsugae crucial. Field surveys of predators associated with A. tsugae in the Pacific Northwest identified a strong correlation between A. tsugae abundance with Laricobius nigrinus and two species of silver fly, Leucopis argenticollis and Leucopis piniperda. Flies in the genus Leucopis are known …

Long-Term Forest Carbon Storage And Structural Development As Influenced By Land-Use History And Reforestation Approach, Andrea Rose Urbano

Graduate College Dissertations and Theses

Temperate forests are an important carbon sink, yet there is uncertainty regarding land-use history effects on biomass accumulation and carbon storage potential in secondary forests. Understanding long-term biomass dynamics is important for managing forests as carbon sinks and for co-benefits such as watershed protection and biodiversity. However there are many unanswered questions regarding these dynamics in northeastern U.S. forests: How have secondary forests of the U.S. Northeast recovered post nineteenth century agricultural abandonment? How has the region's extensive land-use history influenced long-term structural development and aboveground carbon storage? To answer these questions, we employed a longitudinal study based on twelve …

Integrating Management For Old-Growth Characteristics With Enhanced Carbon Storage Of Northern Hardwood-Conifer Forests, Sarah Eliot Ford

Graduate College Dissertations and Theses

Forest management practices emphasizing stand structural complexity are of interest across the northern forest region of the United States because of their potential to enhance carbon storage. Our research is nested within a long-term study evaluating how silvicultural treatments promoting late-successional forest characteristics affect aboveground biomass development in northern hardwood forests. We are testing the hypothesis that biomass development (carbon storage) will be greater in structural complexity enhancement (SCE) treatments when compared to conventional uneven-aged treatments. SCE treatments were compared against selection systems (single-tree and group) modified to retain elevated structure. Manipulations and controls were replicated across 2-hectare treatment units …

Lidar Remote Sensing Of Forest Canopy Structure: An Assessment Of The Accuracy Of Lidar And Its Relationship To Higher Trophic Levels, Christopher Felix Hansen

Graduate College Dissertations and Theses

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 …