Forest Sciences Commons^™

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 …

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 …

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 …

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. …

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 …

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 …

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 …

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 …