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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Empowering collaborative forest restoration with locally relevant ecological research

Matonis, Megan Shanahan 29 September 2015 (has links)
<p> Collaborative forest restoration can reduce conflicts over natural resource management and improve ecosystem function after decades of degradation. Scientific evidence helps collaborative groups avoid undesirable outcomes as they define goals, assess current conditions, design restoration treatments, and monitor change over time. Ecological research cannot settle value disputes inherent to collaborative dialogue, but discussions are enriched by locally relevant information on pressing natural resource issues. I worked closely with the Uncompahgre Partnership, a collaborative group of managers, stakeholders, and researchers in southwestern Colorado, to develop research questions, gather data, and interpret findings in the context of forest restoration. Specifically, my dissertation (1) explored ways to better align collaborative goals with ecological realities of dynamic and unpredictable ecosystems; (2) defined undesirable conditions for fire behavior based on modeling output, published literature, and collaborative discussions about values at risk; (3) assessed the degree to which restoration treatments are moving forests away from undesirable conditions (e.g., homogenous and dense forests with scarce open habitat for grasses, forbs, and shrubs); and (4) looked at the validity of rapid assessment approaches for estimating natural range of variability in frequent-fire forests. </p><p> The current practice of defining desired future conditions pulls managers and stakeholders into command-and-control thinking and causes them to dream away resource tradeoffs and the unpredictability of forest change. Instead, moving ecosystems away from undesirable states and reducing unacceptable risk might allow for diverse and socially acceptable conditions across forested landscapes. The concept of undesirable conditions helped the Uncompahgre Partnership come to agreement over types of fire behavior and stand conditions they wanted to avoid through management. I determined that restoration treatments on the Uncompahgre Plateau are generally moving forests away from undesirably dense conditions that were uncommon prior to Euro-American settlement. My assessment was largely based on data collected during collaborative workdays with the Uncompahgre Partnership. Our rapid assessment approach for estimating historical forest structure took a quarter of the time required for scientifically rigorous stand reconstructions, and it provided reasonably accurate estimates of tree density and spatial patterns. </p><p> Our data on historical stand structure revealed that fragmentation and loss of open grass-forb-shrub habitat between tree groups were the most dramatic and undesirable changes occurring in frequent-fire forests over the past century. Many restoration treatments are focused on restoring spatial patterns in tree groups, with little attention to spatial patterns in open grass-forb-shrub habitat. I determined that the juxtaposition of tree groups with grass-forb-shrub habitat >6 m from overstory trees is important for restoring understory cover, diversity, and composition. Focusing on undesirable conditions in stands, such as high tree density and scarcity of grass-forb-shrub habitat, can help collaborative groups find common ground and design treatments that restore structure, composition, and processes in forest ecosystems.</p>
2

Stand Level Growth and Survival Equations for Cutover Sites Loblolly Pine Plantations in the Mid-Gulf Region of Southern United States

Bartaula, Binayak 11 October 2017 (has links)
<p> Improved equations for predicting future dominant height, diameters, and number of surviving trees in a forest stand were developed for loblolly pine in the mid-Gulf region of southern United States using tree data from 115 stands across the region. The data were split into two sets and models were fitted on each data set using contemporary statistical modeling approaches in SAS<sup>&reg;</sup> and R<sup>&reg;</sup> software. Several models were fitted and compared. Fitted models were evaluated based on two-fold cross validation techniques. The best equations had high fit indices and acceptable prediction standard errors. Model parameter estimates were significant at 5% significance level and exhibited logical model behavior. In the future, the system level performance of these equations will be evaluated after which the equations will be incorporated into the Cutover Sites Loblolly Pine growth and yield simulator developed and maintained by the Mississippi Forest and Wildlife Research Center.</p><p>
3

Changes in forest biomass and overstory-understory species similarities in the context of changing land ownerships

Pandit, Karun 10 September 2016 (has links)
<p> There has been an unusual shift in timberland ownerships in the United States over the past few decades, in which mostly Forest Product Companies have divested properties to institutional owners, like Timber Investment Management Organizations and Real Estate Investment Trusts. Northeast region of the country has been influenced by this trend. Studies have suggested changes in harvesting, silviculture, and conservation efforts under new ownerships may alter forest structure and resiliency. However, there is little documentation on the spatial pattern of such ownership change and its effect on forest dynamics. This dissertation tries to address some of these knowledge gaps by applying a variety of spatial and statistical analyses to Forest Inventory and Analysis (FIA) data from 2003 to 2012. In Chapter 2, I assessed spatial pattern of change in timberland ownerships and linked these incidences with socio-ecological variables. Largest observed shift was from industrial to institutional ownership, a net increase of only 1% in institutional timberlands. However, there was a significant clustering pattern, and clusters were significantly related to forest type, distance from urban center and distance from road. In Chapter 3, I explored changes in aboveground biomass (?AGB) among different ownerships, harvesting, and forest types, and other selected factors. Overall, a positive ?AGB (671 lb/ac/yr) was observed, with Non Industrial Private Forest (NIPF) timberlands having higher growth than industrial and institutional timberlands. Among forests, Elm-Ash-Cottonwood had the best growth, and among harvesting regimes, plots harvested before first measurement had highest growth. Ownership, harvest, disturbance, silvicultural treatment, forest type, stand age, site index, and precipitation were significantly related to &Delta;AGB. In Chapter 4, I compared three indices used to characterize similarity between overstory-understory tree species composition and assessed potential future change in forest composition. Ownership, forest types, precipitation, stand age, site index, stand origin, slope, elevation, proximity to road and urban centers all contributed to explaining variation in change in similarity indices. Among ownership categories, industrial and institutional ownerships had greater dissimilarity over time, in contrast to other ownerships. The final chapter discusses some potential implications of these results to northern forest structure, resiliency and sustainable production.</p>
4

THE EFFECTS OF LAND USE AND LAND USE CHANGE ON THE YIELDS OF STREAMS IN MASSACHUSETTS.

MRAZIK, BRIAN REED 01 January 1976 (has links)
Abstract not available
5

AN ASSESSMENT OF RESIDUE UTILIZATION AT MASSACHUSETTS SAWMILLS (FINANCIAL, ECONOMIC)

DENNISON, STEVEN E 01 January 1984 (has links)
A general assessment model of industrial wood residue use was devised and tested using the sawmill industry in Massachusetts. Two analytical approaches were used in the model. The first employs financial analyses of individual mills (in various production strata) to determine the profitability of their residue operations. An economic analysis used to determine the need for public intervention is also part of this approach. The second part of the model utilizes a scoring technique to evaluate the technical components in the sawmill's residue operation. It is intended primarily as a tool to complement the economic analysis in the first approach. Sixty individual firms, comprising 40 percent of the State's sawmill industry population in 1980, responded to a questionnaire survey aimed at examining their residue operations. Residue prices and equipment costs (obtained from primary and secondary data sources) were applied to the annual physical flow of residues and equipment at each mill. From these data cash flows for the evaluation period of each residue operation were developed. The residue inventory indicated that 86 percent of all residues generated in Massachusetts were sold. According to the net present worth values calculated in the financial analyses, 95 percent of all sawmills selling their residues did so at a profit. Residue operations at the other mills could be improved mainly through changes in equipment use, residue pricing, and greater attention to marketing. Because of the general profitability of residue operations in the state, an economic analysis was not conducted for this study. For the technical components analysis, the establishment of a standard threshold value allowed operations to be compared on a technical basis to other mills in the same production class. The threshold index also provided a ranking that could be used in determining the need for public intervention under a limited budget.
6

IMPACT OF SWIDDEN AGRICULTURE AND SUBSISTENCE HUNTING ON DIVERSITY AND ABUNDANCE OF EXPLOITED FAUNA IN THE ITURI FOREST OF NORTHEASTERN ZAIRE (PYGMY)

WILKIE, DAVID SCOTT 01 January 1987 (has links)
This 18 month study examined the impact of long-term recurrent roadside swidden cultivation and subsistence hunting on the composition and abundance of exploited fauna and the ability of roadside post agricultural regrowth vegetation to support exploitable populations of these animals. A computer model was also developed to graphically represent the spatial patterning of horticultural land-use and forest vegetation regeneration under a variety of demographic and land-use conditions. Track counts and pellet group counts in conjunction, are an effective means to estimate faunal composition and relative abundance within a tropical moist forest. Densities of forest duikers, which are most commonly exploited and are the most important species group dietarily, are comparable in post-agricultural regrowth forest and uncut forest within 5km of the road. Hunting success and bushmeat capture weights are comparable from hunts conducted in regrowth and uncut forest. Hunters concentrate 56% of their effort in regrowth forest that constitutes only 26% of the available forest within 3km of the road. Given that subsistence hunting pressure is greater in regrowth forest within 3km of the road and that ungulate densities are comparable in regrowth and uncut forest, this study concludes that post-agricultural forest can and does provide substantial and sustained quantities of bushmeat for consumption by local human populants and may support a higher biomass of exploitable fauna than comparable areas of uncut forest. The ability of forest faunal populations to withstand the intensive exploitation associated with widespread market hunting is however dubious. The spatial patterning of horticultural land-use in the Ituri forest can be effectively stimulated using a very simple set of rules to govern forest clearing and post-abandonment regeneration.
7

THE GRAY SQUIRREL (SCIURUS CAROLINENSIS)--ABUNDANCE, DISTRIBUTION, AND UTILIZATION OF AN URBAN HABITAT (SPRINGFIELD, MASSACHUSETTS).

WILLIAMSON, ROBERT DOUGLAS 01 January 1978 (has links)
Abstract not available
8

MORTALITY PATTERNS OF RADIO-MARKED COYOTES IN JACKSON HOLE, WYOMING

TZILKOWSKI, WALTER MATTHEW 01 January 1980 (has links)
Coyote (Canis latrans) mortality was measured in Jackson Hole, Wyoming. The study area included portions of Grand Teton National Park, National Elk Refuge and Bridger-Teton National Forest. Coyote exploitation is prohibited on both the National Park and Refuge, environments minimally influenced by man. Ninety-two coyotes, 43 males and 49 females, at least 4 months of age or older, were captured during 5 trapping periods from December 1973 to September 1976. Coyotes were collared with radio telemetric transmitters which revealed geographic location and served as mortality indicators. Thirty-three pups ((LESSTHEQ) 7 weeks) were ear-tagged; two were subsequently captured and radio-marked. Forty-one radio-marked coyotes, 18 males and 23 females, were recovered. Only 1 ear-tagged pup was recovered. A positive linear relationship existed between recovery time (days) and age (years) at marking. Eighty-five % (N = 41) of the recoveries were during September through May. Ninety-three % of the mortalities were man-caused. Mortality causes of recovered coyotes included: shot, 80.5%; trapped, clubbed, snow-machined and starvation, 2.4%; road-killed and unknown, 4.9%. Annual (June to subsequent May) recovery rates were: 1974-75, 25% (N = 47); 1975-76, 5% (N = 18); and 1976-77, 40% (N = 25). Recovery rates from marking to recovery from the composite sample were: year 0, 26% (N = 90); year 1, 18% (N = 65); and year 2, 8% (N = 47). Shooting mortality rates (h(,x)) for the 0 years since marking class of the young-of-the-year Jackson Hole coyotes (0.4194) were compared to rates from Curlew Valley (0.3125) and Yellowstone National Park (0.2531). Mean total mortality rates (q) were: 0.7339, Curlew Valley; 0.5596, Yellowstone National Park; and 0.4561, Jackson Hole. The mean total mortality rate (q) was 0.3783 and the mean shooting mortality (h) was 0.2540 for Jackson Hole coyotes. Monthly survival rates were higher in 1975-76 that 1974-75. Female young-of-the-year survival was less (P = 0.03) for 1974-75 than 1975-76. There was no difference (P > 0.05) between years in survival rates for males or adult and yearling females. Estimates of areas of utilization (22 January 1975 to 22 April 1975) were computed for 19 coyotes. The mean area of utilization of 5 adult or yearling males was 35.5 km('2) (+OR-) 18.9, and for 13 adult or yearling females was 70.1 (+OR-) 80.3. Coyotes radio-marked primarily in Grand Teton National Park and the National Elk Refuge had mortality patterns similar to other coyote populations exploited by man.
9

Structural attributes, disturbance dynamics, and ecosystem properties of old-growth forests in western Massachusetts

D'Amato, Anthony William 01 January 2007 (has links)
Natural disturbance patterns, forest structural attributes, patterns of nitrogen availability, and the abundance and composition of understory vegetation were studied in eighteen old-growth stands in western Massachusetts. Dendroecological analyses indicated that disturbance regimes for these systems were dominated by relatively frequent, low intensity disturbances (average of 5.0% canopy area disturbed per decade) operating randomly on the landscape. Comparisons of dendroecological patterns with model simulations of past hurricane events and historical documents suggested that broad-scale disturbances, such as hurricanes and ice storms, resulted in common disturbance peaks in the 1790s, 1820s, and 1920s at several study areas separated by over 50 km. No stand-replacing disturbances were detected at any old-growth area during the period examined (1700-1989). Comparisons of structural characteristics in old-growth and second-growth hemlock forests illustrated that old-growth stands exhibit a higher degree of structural complexity compared to second-growth hemlock forests. In particular, old-growth stands had larger overstory trees and a greater abundance of downed coarse woody debris (135.2 versus 33.2 m3/ha) and snags (21.2 versus 10.7 m3/ha) compared to second-growth systems. The range in variation of structural attributes within my old-growth study areas was similar to those in other old-growth eastern hemlock forests located on more moderate terrain in the Upper Midwest and New York. This range in variation was related to differences in disturbance history and site productivity among old-growth stands. Soil measurements indicated that there were no detectable differences in soil characteristics, such as total C and N, between old-growth and second-growth hemlock stands; however, inorganic N (NO3-N and NH4-N) availability was much greater in old-growth stands. In contrast, differences existed in soil characteristics and N availability between old-growth hemlock and old-growth northern hardwood forests, with hardwood dominated systems exhibiting lower forest floor C:N ratios and greater amounts of inorganic N. Old-growth hemlock stands had higher species richness and diversity, as well as a greater abundance of understory herbs and shrubs, and tree seedlings and saplings compared to second-growth forests. In addition, several common understory plants, including Aralia nudicaulis, Dryopteris intermedia , and Viburnum alnifolia, were more abundant in old-growth stands.
10

Soil moisture, forest productivity and ecological land classification in central Massachusetts

Leighton, Adrian D 01 January 2005 (has links)
Throughout much of the United States, systems of ecological land classification are used to divide the forested landscape into units that are biologically and operationally meaningful. No such system currently exists in central Massachusetts, however, due to the extensive and prolonged effects of human land use. Initial research on a series of State Forests in central Massachusetts indicate that physical site characteristics such as the presence of a hardpan, soil texture and type of glacial deposition can be correlated with patterns in vegetation distribution. These factors are similar to those used by W. B. Leak in creating an ecological land type (ELT) classification for the White Mountain National Forest in New Hampshire. A system was created to adapt and transfer the White Mountain ELTs to central Massachusetts. The system was then applied to a variety of sites in central Massachusetts at two different scales. The habitat classification system reflected general trends of vegetation composition and productivity, particularly at a local landscape level, but further work is needed to better account for the effect of land use history and local ecological variation. An underlying assumption of ecological land classification is that vegetation is most strongly influenced by site factors that are related to soil moisture availability. Direct soil moisture measurements were made on a variety of sites throughout a season at Cadwell Memorial Forest in Pelham, Massachusetts. Analysis showed a relatively poor correlation between soil moisture measured that year and long-term site productivity. However, the pattern of short term (weekly) variation in soil moisture was related to general trends in productivity. The hydrologic model, TOPMODEL, was used to create a relative wetness potential index within a GIS framework to predict site productivity based on potential soil moisture availability. While this model showed some potential in predicting general soil moisture status, it was not well correlated with the direct soil moisture measurements.

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