Life Sciences Commons^™

Age, Size, And Composition Of Selected Old-Growth Shortleaf Pine Stands In The Upper Buffalo River, Arkansas, Willa Avery Thomason

Graduate Theses and Dissertations

Shortleaf pine (Pinus echinata) approaches the westernmost limits of its range in the Arkansas Ozarks. Despite heavy logging of shortleaf pine throughout its range during the 19th and 20th centuries, the species was not easily accessible for harvest and transportation in the most rugged areas of the Boston Mountains and, as a result, there are a few extant stands of old-growth shortleaf pine in the region. The shortleaf pine stands in the interior Boston Mountains are unusual in that they exist primarily above bluff lines at topographic breaks in the hardwood canopy and are not disturbed by fire as frequently …

Impacts Of Climate And Wildfire On Western Larch Regeneration, Spencer T. Vieira

Graduate Student Theses, Dissertations, & Professional Papers

Fire plays a critical role in forests of the western United States (US), but as wildfire and climate deviate from historical patterns, increasing fire activity may significantly alter forest ecosystems. To understand the impacts of changing climate and wildfire activity on conifer forests, we studied the impact of wildfire and annual post-fire climate on western larch (Larix occidentalis) regeneration. We destructively sampled 1651 seedlings from 57 sites within 32 fires that burned at moderate or high severity from 2000-2015 in the northwestern US. Using dendrochronological methods, we estimated germination years of seedlings to calculate annual recruitment rates. We …

Climatic Drivers Of Growth In Mixed Conifer Forests Of The Sierra Nevada For Different Tree Sizes And Thinning Treatments, Andrew M. Hirsch

Graduate Theses, Dissertations, and Problem Reports

The Mediterranean region of northern California is projected to get increasingly warmer under all Intergovernmental Panel on Climate Change (IPCC) emission scenarios, with future precipitation projections not showing much of a trend. This poses a problem to the already dry summers that are experienced in the Mediterranean region of California. If precipitation does not increase alongside temperatures, the dry seasons will likely only get drier. The use of dendroclimatology to assess how mixed conifer species in the Sierra Nevada responded to past climate is a key resource that can be used to infer how trees may respond to a future …

The Historic Fire Return Interval And The Ecological Effects Of Fire Suppression On Montane Longleaf Pine Dominated Ecosystems In Northwestern Georgia., Christopher Waters

Master of Science in Integrative Biology Theses

Longleaf pine ecosystems have experienced pronounced declines across the southeastern United States since Euro-American settlement took place in the late 19th century. These declines were primarily caused by federal fire suppression policies implemented in the 1920’s, in combination with resource harvesting and land use conversion. In an absence of fire, tree species composition of frequently burned xeric ecosystems progressively becomes more mesic and fire-intolerant (i.e. mesophication). The change in the species composition and historic fire frequency of a montane longleaf pine ecosystem located in Sheffield Wildlife Management Area (WMA), Paulding County, Georgia was investigated. The change in forest composition …

Dendrochronological Methods To Examine Plant Competition With Changing Fire Regimes In Desert And Forest Ecosystems, Rebecca Irene Lee

Theses and Dissertations

Human activities are changing wildfire regimes globally through ignition, spread of invasive species, fire suppression, and climate change. Because of this, ecosystems are experiencing novel fire regimes that may alter plant growth and patterns of succession. Annual growth rings are one metric that can track changes in tree and shrub growth patterns over time in response to changing fire frequency. In Chapter 1 we explored the effects of fire on resprouting native shrubs in the Mojave Desert. Fires are becoming increasingly frequent due to the spread of highly flammable invasive grasses in the region. We monitored growth and fruit production …

Using Tree-Ring Growth And Stable Isotopes To Explore Ponderosa Pine Ecophysiological Responses To Climate Variability And The 2012-2015 California Drought, Rachel M. Keen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Climate warming in recent decades has resulted in more frequent and severe drought events in the western United States. These changes are projected to continue, making it exceedingly important to understand how forests respond to severe drought stress, and how we can manage these forests to reduce mortality during future events. The 2012-2015 California drought is a recent example of a severe, multi-year drought that was coupled with an epidemic-scale outbreak of western pine beetle, killing nearly 90% of ponderosa pines in the central and southern Sierra Nevadas. In the first portion of this study, we compared pairs of surviving …

Analysis And Conservation Of Native Forests At Kessler Mountain Fayetteville, Arkansas, Alan James Edmondson

Graduate Theses and Dissertations

Kessler Mountain in Fayetteville Arkansas has long been recognized for its beauty and natural resources. Parts of Kessler Mountain have been homesteaded and developed in the past, but most of the mountain has remained relatively undisturbed. The planned development of over 4,000 housing units to cover Kessler Mountain stimulated controversy and consideration of other management alternatives. A twist of fate involving an economic recession, a dedicated group of outdoor recreation enthusiasts, and environmental conservationists led to the permanent protection of 384 acres in the Kessler Mountain Regional Park. To help evaluate the natural resources at Kessler Mountain, forest composition, structure, …

Evaluating Climate And Environmental Drivers Of Tree Species’ Growth Within The Northern Forest, Rebecca Stern

Graduate College Dissertations and Theses

Northeastern forests are in a period of immense change. While forests are inherently dynamic ecosystems, a range of environmental challenges may cause unique and uncertain transformations within forests moving forward. How trees in northern forests respond to these environmental and anthropogenic changes remains uncertain; reductions and increases in the growth of various species and shifts in current species’ ranges may take place.

I analyzed associations between tree growth (assessed using xylem increment cores) and a range of site, climate, and pollution deposition variables for seven major tree species in Vermont. First, I looked at red oak (Quercus rubra L.), a …

Detecting Balsam Woolly Adelgid Infestations Using Tree Rings, Morgan Lane Leef

Graduate Theses, Dissertations, and Problem Reports

Balsam woolly adelgid (BWA), Adelges piceae(Ratzeburg), is a sap-sucking, exotic invasive insect that arrived in North America from central Europe around 1900. Since then, its range has expanded from New Brunswick, Canada to the southern Appalachian Mountains. It is a threat to all North American true-fir species, but populations can be controlled by cold continental winters. Adelgid feeding leaves noticeable traces on the wood tissue (“rotholz”) and causes a temporary positive radial growth response among affected trees. The purpose of this research was to determine dates of initial outbreaks, balsam fir radial growth change during outbreaks, and the relationship …

Baldcypress And Black Willow Growth Response To Contrasting Flood Regimes, Climate, And Competition, In The Atchafalaya Basin, Louisiana, Alicia Louise Mcalhaney

LSU Master's Theses

Wetlands are dynamic ecosystems distinguished by their dependence on fluctuations of hydrologic influence. Although it is generally accepted that that flooding is a strong influence on growth, and that effects vary depending on whether water is stagnant or flowing, several aspects of flood characteristics and several tree species remain poorly investigated. One source of variability that has not been investigated is how flooding, climate, and competition among trees interact to control growth of individual trees. The objective of this study was therefore to 1) investigate effects of temporally varying hydrology and climate on growth of baldcypress and black willow trees …

Demography And Dendrochronology Of A Disjunct Population Of Eastern Hemlock In Southwestern Ohio, Marie Johnson

Browse all Theses and Dissertations

Edge and isolated plant populations provide information about the resilience and the most basic resource needs of a species. Plant demography examines changes in population size and structure over time. An isolated, disjunct eastern hemlock population in Clifton Gorge State Nature Preserve, Yellow Springs, Ohio consists of two distinct subpopulations each with different environmental characteristics, reproductive capacities, and health ratings. Both subpopulations at Clifton Gorge were found to exhibit significant decreases in average annual ring width through time. Linear regression modeling determined that average annual growing season precipitation and temperature were the strongest predictors of these growth trends. A comparative …

Growth Dynamics Of Black Spruce (Picea Mariana) Across Northwestern North America, Anastasia E. Sniderhan

Theses and Dissertations (Comprehensive)

The impacts of climate change have been widely documented around the world. One of the most rapidly changing areas is the boreal forest of North America. The extent of change has been such that there have been shifts in long-standing climate-growth relationships in many boreal tree species; while the growth of many of these high-latitude forests were formerly limited by temperature, warming has increased the evapotranspirative demands such that there is widespread drought stress limiting productivity in the boreal forest. With the importance of the boreal forest as a global carbon sink, it is imperative to understand the extent of …

Demographics And Growth History Of Whitebark Pine On Undisturbed Sites Across The Northern Us Rocky Mountains, Sarah Flanary

Graduate Student Theses, Dissertations, & Professional Papers

Along with fluctuating precipitation and temperatures in the form of climate change, whitebark pine (Pinus albicaulis) has seen a territory wide increase in mortality leading to a decline in population. While the most direct influences on whitebark pine health and mortality are mountain pine beetle (Dendroctonus ponderosae) outbreaks, fire exclusion policies, and the spread of white pine blister rust (Cronartium ribicola), climate change can impact the intervals and severity of such beetle, rust, and fire disturbances, and may affect the growth and health of whitebark pine directly. The objectives of this study were to identify whitebark pine stands within the …

The Impact Of Climate And Elevation On The Growth And Mortality Of Piñon Pine, Alice M. Fretz

Biology ETDs

The Southwestern United States is currently experiencing severe drought, resulting in the mortality of many tree species. Piñon-juniper woodlands are an extensive biome in the Southwest, and are highly vulnerable to extended periods of drought that lead to tree mortality. Specifically, Pinus edulis populations are decreasing due to increasingly arid conditions. I used dendrochronology to investigate how tree growth rings of Pinus edulis reflect severe drought in living and dead trees. I also investigated how severe drought affects Pinus edulis along an altitudinal gradient. Tree core samples were taken from currently living and dead trees, as well as from trees …

Exploring Historical Coffee And Climate Relations In Southern Guatemala: An Integration Of Tree Ring Analysis And Remote Sensing Data, Diego Pons

Electronic Theses and Dissertations

This dissertation makes use of a physical geography perspective to examine the relationship between agriculture and climate in Guatemala using dendrochronology. I examined the potential of high-resolution climate proxy data from dendrochronology to help fill in the gaps of past climate information to better understand the natural and anthropogenic variability of precipitation which, in turn, can inform Guatemala’s agriculture sector. This research has demonstrated successful cross-dating and climate sensitivity of Abies guatemalensis in the Pacific slope of Guatemala. Based on this, I have produced a 124-year record of mean precipitation from June-July-August. The mean precipitation from June-July-August at this site …

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 …

White Spruce (Picea Glauca), Moose (Alces Alces) And The Origin Of A Zootic Disclimax Community On Isle Royale, Stephen C. Caird

All NMU Master's Theses

Understory herbivory combined with canopy loss alters trajectories of forest succession, and in extreme cases may produce novel landscapes dominated by the groundcover layer. I investigated the response of woody species to savannas which have emerged in Isle Royale National Park as a result of moose herbivory. I used dendrochronological methods and microsite plots to describe the spatial, temporal, and competitive responses of white spruce (Picea glauca), a non-palatable species, to the savanna environment. Most tree species had lower densities in savannas, however bird-dispersed species mountain ash (Sorbus decora) and chokecherry (Prunus virginiana) were …

Historical Tidal Forest Composition And Contemporary Woody Recruitment Following Dam Removal From A Mid-Atlantic Coastal Plain Tidal Freshwater Wetland, Richard E. Ward Jr.

Theses and Dissertations

Tidal freshwater forest restoration after dam removal has been unexplored to date. This study elucidated pre-dam forest composition, as well as post-dam edaphic and microtopographical attributes and woody species recruiting along a narrow ecotone of a 29.3-ha tidal freshwater wetland. The ≈65-year-old historical forest (15 species, 200 stems ha-1) and ≈7-year-old contemporary forest (40 species and 11,009 stems ha-) community dominants were dissimilar (Fraxinus spp. vs. Liquidambar styraciflua, respectively). Pre-dam environmental conditions were unknown. Post-dam edaphic water content, organic matter, redox potential and microtopography differed significantly across tidal sites but were less variable in non-tidal sites. Shifts in the contemporary …

Drought Sensitivity Of Slash Pine And Longleaf Pine Deduced By Tree Ring Analysis, Conor Madison

Honors Theses and Capstones

Annual tree rings give us the opportunity to investigate the adaptation of trees to climate and environmental changes over a long period of time. In particular, the physical characteristics of each ring (width and earlywood and late wood differentiation) can be used to reconstruct past environment conditions. Physiological responses of trees will be evaluated for two conifers species, i.e. Longleaf pine and Slash pine, giving the opportunity to compare the two species and understand how each species (Longleaf pine and Slash pine) adapt their water use to thrive in such extreme environments. Growth data will then be related to the …

Assessing Growth Response To Climate Controls In A Great Basin Artemisia Tridentata Plant Community, Lorenzo F. Apodaca

UNLV Theses, Dissertations, Professional Papers, and Capstones

An assessment of the growth response of key vegetative species to climatic variability is vital to identifying possible local impacts on ecosystems faced with imminent climate change. With current climate projections in Nevada predicting a shift to an even more arid climate with greater year-to-year variability, the imperative exists to identify the effects of specific climatic controls on plant growth and to research methods to assess large-scale vegetative changes, especially in more remote areas where readily available data sets may be lacking. This study utilized annual growth ring indices constructed from big sagebrush (Artemisia tridentatassp.tridentata) stems collected in Spring Valley, …

Tree Growth Dynamics, Fire History, And Fire-Climate Relationships In Pine Rocklands Of The Florida Keys, U.S.A., Grant Logan Harley

Doctoral Dissertations

Pine rocklands are globally endangered, fire-maintained communities currently restricted to small habitat areas in southern Florida, Cuba, and the Bahamas. The purpose of this dissertation research was to identify the long-term ecological disturbance regimes and climatic trends responsible for the persistence of pine rocklands, and examine how human-induced changes during the 20^th century contributed to decline of these communities. This research applied techniques of dendrochronology in extreme southern Florida, in a subtropical region where tree‐ring science has never been applied, to increase the understanding of how anthropogenic and natural disturbance events have decreased the spatial distribution of South Florida …

A 1,461-Year Growing Season Precipitation Reconstruction For The Carolina Coastal Plain, Kathryn Perkins Wolff

Graduate Theses and Dissertations

A recollection and dating of ancient cypress trees and subfossil logs was performed at Black River, North Carolina, and the separate Black River, South Carolina. The new updated and expanded chronologies date from AD 365 to 2010 and 549 to 2010, respectively. Baldcypress ring-width chronologies are dominated by high inter-annual to decadal variability and do not tend to capture century scale fluctuations in tree-ring growth that could be associated with centennial scale change in climate. The tree-ring chronologies were standardized with a technique designed to preserve low frequency variance known as regional curve standardization. The two chronologies were averaged into …

Age, Forest Structure, And Disturbance History Of Five Potential Old-Growth Forests In Eastern Kentucky's Cumberland Plateau, Adrienne Michelle Cooper

Online Theses and Dissertations

The Cumberland Plateau (CP) is an ecoregion of global importance, yet its extent of old- growth forest (OG) is not well known. Due to its rarity and importance, understanding what OG remains is needed to deduce the region's health. This study described five potential OG forests in eastern Kentucky. Sites possessing >5 trees/ha established prior to 1780, and being similar in disturbance history and forest structure to other regional OG were to be considered OG. Shillalah Creek (SC) and Hensley-Pine Mountain (HP) possess no in plot trees established prior to 1780, show evidence of stand-wide disturbance during the 1930's, are …

Historic Fire Regimes On Eastern Great Basin (Usa) Mountains Reconstructed From Tree Rings, Stanley G. Kitchen

Theses and Dissertations

Management of natural landscapes requires knowledge of key disturbance processes and their effects. Fire and forest histories provide valuable insight into how fire and vegetation varied and interacted in the past. I constructed multi-century fire chronologies for 10 sites on six mountain ranges representative of the eastern Great Basin (USA), a region in which historic fire information was lacking. I also constructed tree recruitment chronologies for two sites. I use these chronologies to address three research foci. First, using fire-scar data from four heterogeneous sites, I assert that mean fire interval (MFI) values calculated from composite chronologies provide suitable estimates …