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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

FOREST STRUCTURE UNDER HUMAN INFLUENCE NEAR AN UPPER-ELEVATION VILLAGE IN NEPAL

Bolton, Gary Howard January 2005 (has links)
Across the southern slope of the Nepal Himalaya lie large areas of upper-elevation broadleaf evergreen forest. Resources extracted by subsistence villagers include hand-cut tree-leaf fodder for livestock, fuelwood, and poles for construction of herders’ shelters. Indigenous use of forest products may be altering forest structure and resource availability in Nepal. This research examined forest structure and its relationships with human use of forest products near the upper-elevation village of Chimkhola in west-central Nepal. In the 150-ha forest study area, mean density and standard error (SE) of trees >10 cm dbh was 817 (30) stems ha⁻¹ and mean (SE) total basal area was 44 (3.2) m² ha⁻¹. Cluster analysis of density data for 32 tree species suggested three forest communities: a Symplocos-Quercus community, a Symplocos-mixed evergreen community, and a Rhododendron-Symplocos community. Ordination by principal components analysis of tree species densities indicated a relationship between community structure and a cutting index that increases with harvest intensity. Size-class distributions of important fodder-resource oak species suggested Quercus lamellosa is in decline, but Q. oxyodon and Q. semecarpifolia may be reproducing successfully. Age-diameter regression equations of three evergreen tree species showed growth rate of Symplocos ramosissima to be approximately twice that of Machilus duthei or that of Lindera pulcherrima. The fast growth rate and shade tolerance of S. ramosissima appear to confer a successional advantage. I assessed sustainability of harvest of pole-size (5-10 cm dbh) S. ramosissima used in herders’ shelters, by comparison of harvest and replenishment rates. Mean (SE) density of pole-size S. ramosissima was 375 (32) stems ha⁻¹ in the study area. If the total harvest was distributed evenly across the forest area, it would be 34 stems ha⁻¹ yr⁻¹ and would not exceed the replenishment rate. However, harvest was concentrated in the Symplocos-Quercus community, closest to the village and agricultural fields. Using stump counts as a proxy of relative harvest intensity, harvest rates were sustainable in the Symplocos-mixed evergreen and Rhododendron-Symplocos communities, but not sustainable in the Symplocos-Quercus community.
2

Forest Biomass Utilization in the Southern United States: Resource Sustainability and Policy Impacts

Guo, Zhimei 01 May 2011 (has links)
As an alternative renewable source for bioenergy, forest biomass has recently drawn more attention from the U.S. government and the general public. Woody biomass policies have been adopted to encourage the new bioenergy industry. A variety of state policy incentives attempt to create a desirable legal climate and lure new firms, imposing two important questions regarding state government policies and the sustainable use of forest resources. This dissertation sheds some light on these questions. The first paper constructs a woody biomass policy index through scoring each statute and weighting different categories of policies from the vantage point of renewable energy investment. It analyzes the disparity in the strength of state government incentives in the woody biomass utilization. The second paper employs a conditional logit model (CLM) to explore the effects of woody biomass policies on the siting decisions of new bioenergy projects. In addition, significant state attributes influencing the births of new bioenergy firms are identified such as resource availability, business tax climate, delivered pulpwood price, and the average wage rate. The third paper uses the Sub-Regional Timber Supply (SRTS) model to examine the regional aggregate forest biomass feedstock potential in Tennessee and to predict the impacts of additional pulpwood demand on the regional roundwood market through 2030. The fourth paper includes the benefits of thinning and logging residues in a dynamic optimization model to analyze how bioenergy policies will impact forest stock, harvest levels, optimal rotation, and silvicultural effort. The results may have substantial implications regarding woody biomass policies, the creation of a new bioenergy industry, and sustainable forest resource management. A lucrative state woody biomass policy support and tax climate can attract new bioenergy businesses. States endowed with abundant forest resources may choose to provide strong tax incentives to spur the birth of new plants. However, overuse of forest biomass can impact roundwood markets and traditional wood processing industries. How government incentives will affect the sustainability of natural resources can be diverse. These findings offer constructive insights in the enactment and implementation of new woody biomass legislation.

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