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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.
141

A computer simulation study of the relative efficiency of several forest sampling techniques as influenced by the spatial distribution of trees found in five major forest types of the Pacific Northwest /

Payandeh, Bijan. January 1968 (has links)
Thesis (Ph. D.)--Oregon State University, 1968. / Typescript (photocopy). Mounted photograph. Includes bibliographical references (leaves 134-145). Also available on the World Wide Web.
142

An evaluation of an inventory projection system : TRIM model predictions vs. forest inventory field measurements in North Carolina /

Mills, John R. January 1987 (has links)
Thesis (M.S.)--Oregon State University, 1987. / Typescript (photocopy). Includes bibliographical references (leaves 78-79). Also available on the World Wide Web.
143

Factors controlling forest successions at Lake Itasca, Minnesota ... /

Lee, Shun Ching. January 1923 (has links)
Thesis (Ph. D.)--University of Chicago. / A Dissertation, submitted to the faculty of the Ogden Graduate School of Science, in candidacy for the Degree of Doctor of Philosophy, Department of Botany. Includes bibliographical references.
144

An efficient formulation and solution method of the even-aged rotation and thinning problem /

Paredes-Veloso, Gonzalo L. January 1986 (has links)
Thesis (M.S.)--Oregon State University, 1986. / Typescript (photocopy). Includes bibliographical references (leaves 34-37). Also available on the World Wide Web.
145

The effect of trade related environmental measures on the forest sector and timber trade of Peninsular Malaysia

Shanmugam, Sugumari January 2015 (has links)
Global concern on illegal logging has led to the imposition of binding trade related environmental measures on trade of timber and timber products by developed countries like the US, EU and Australia. This dissertation examines the effect of the binding measures on Peninsular Malaysia’s forest sector and timber trade. Putnam’s two-level game theory is applied, to demonstrate the interdependence of politics at the international level with the domestic level. There is a need to have a “win-set” between the international and domestic levels whereby an agreement reached by stakeholders at Level II (discussions at the domestic level) will help to make the bargaining at Level 1 a success (bargaining between negotiators which leads to a tentative agreement). In the case of Peninsular Malaysia’s forest sector and timber trade, it has been acknowledged that the measures imposed by the EU through FLEGT VPA/EUTR and to a lesser extent by Australia through its ILPA/ILPAR as well as the US with its Lacey Act amendments, have brought about changes in policy and administration. Thus, the Federal Government of Malaysia, specifically in the FLEGT VPA negotiations have an important task in managing domestic stakeholders’ demands for development, taking into account the unique Federal-State relations on land and forest matters as well as managing its international commitments to ensure trade in sustainable and/or legal timber. The policy reaction of the Federal Government of Malaysia to the measures imposed was analysed using Schoppa’s analysis of the concept of “synergistic linkages” and “reverberation”. On this note, case studies were conducted on Peninsular Malaysia’s forest sector and timber industry as well as the binding measures with specific focus on EU FLEGT VPA/EUTR. To substantiate the findings of the case studies, empirical evidence were gathered from primary interviews with experts from government or agency officials, Timber Industry Associations, environmental and social NGOs and international organizations. Further, focus group discussions were held with four states in Peninsular Malaysia to understand the position of the states. The findings show that it is important for the Federal Government to gain the support and commitment of State Governments on such measures. Therefore, the demands of State Governments for extra funding, resources, equipment and manpower to implement the sustainable and/or legal commitments need to be addressed. Furthermore, NGO criticism about not being properly consulted or given an effective role in government initiatives or meetings, also needs to be taken into account. There is also a need for greater political will by the Malaysian Government, to ensure the success of any negotiations or binding measures imposed. This dissertation indicates the importance of a Level II agreement to ensure the success of a Level I agreement of current negotiations pertaining to Peninsular Malaysia’s forest sector and timber trade.
146

Pollination and seed setting in certain conifers

Fahmy, Tawfik Yousef January 1963 (has links)
Four species of Conifers were used in an investigation on the effect of self-, cross- and open pollination on cone and seed setting. Both Cedrus atlantica and Tsuga canadensis are shown to he completely self-incompatible, and in the latter species, incompatibility is associated with parthenocony. In Chamaecyparis lawsoniana. the individual trees behave differently and show either complete or partial self-incompatibility. Pinus silvestris is found to be partially self-incompatible. Possibly because of the small number of pollen parents used, no crossincompatibility has been demonstrated in any of the four species. The behaviour of pollen in the self-incompatible pollinations is shown to be different in the four species. In C. atlantica. all self-pollinated cones fail to develop and fall off the tree within a few months of pollination. Pollen in the cross-pollinated cones remains dormant for about eight months before it germinates. In T. canadensis, self-pollen does not germinate whatever its position on the cone-scales; hut cross-pollen within a certain radius of the ovules germinates after six to eight weeks. In P. silvestris and C. lawsoniana, all pollen germinates, hut in most self-pollinations pollen-tube growth is inhibited either in the nucellus or the embryo-sac. Experiments on pollen germination in vitro show that pollen of all four species germinates readily at 18° C and higher temperatures. The long period of pollen dormancy in the female cones of C. atlantica is partly explained by the direct effect of temperature. The nature of the incompatibility reaction is discussed, and it is suggested that in all four species the reaction is more likely to be oppositional rather than complementary.
147

Nondestructive Evaluation of Southern Pine Lumber

Nistal Franca, Frederico Jose 12 October 2017 (has links)
<p> Southern pine (SP) lumber is the primary softwood material in the United States. The main procedure during lumber grading process is the identification of the strength reducing characteristics that impacts the modulus of rupture (MOR). Non-destructive evaluation technology can be used to identify higher-stiffness material. This study investigated the use of vibration methods to evaluate the mechanical properties of southern pine lumber. Significant correlations between the properties determined by non-destructive techniques and the static MOE were found. No strong correlations were found for MOR because it is related to the ultimate strength of material, often associated with the existence of localized defects, such as a knot. Non-destructive measurements, visual characteristics, and lumber density were used as independent variables. Linear models were constructed to indirectly estimate the MOE and MOR. The variables selected was dynamic modulus of elasticity (dMOE) to predict MOE. Adding density and knot diameter ratio to the model it was possible to develop a prediction model for MOR. It was possible to improve predictability of strength (MOR) with a combination of non-destructive and knot evaluation.</p><p>
148

Long-Term Effects of Post-Fire Forest Structure on Understory Vegetation in Larch Forests of the Siberian Arctic

Pena, Homero, III 16 December 2017 (has links)
<p> Climate warming is increasing fire severity in boreal forests and can alter forest structure and carbon (C) dynamics in Cajander larch (<i> Larix cajanderi</i>) forests of Siberia, which occur over C and ice-rich yedoma permafrost. Altered forest structure may impact understory vegetation through changing canopy cover, permafrost thaw depth, and soil temperatures. The primary objective of this study was to assess the long-term impacts of fire-driven changes in tree density on understory composition, diversity, and C pools and the underlying soil organic layer (SOL). Shrubs dominated low density stands, likely from reduced canopy cover and thaw depth, while mosses dominated high density stands. Consequently, understory C pools decreased from 415.46 to 158.87 g C m<sup>&ndash;2</sup>. Total SOL C pools remained unchanged as tree density increased. These findings suggest that fire-driven changes in tree density may alter understory composition and C pools, which could impact nutrient/water cycling and permafrost stability. </p><p>
149

The polygonal graphing of climatic factors of forest areas of British Columbia

Pillsbury, Richard Washburn January 1945 (has links)
[No abstract submitted] / Science, Faculty of / Botany, Department of / Zoology, Department of / Graduate
150

Population dynamics of spiny dogfish, Squalus acanthias, in the NW Atlantic

Silva, Helder Guerreiro Marques da 01 January 1993 (has links)
Dynamics of the NW Atlantic population of the spiny dogfish are investigated. The population underwent a three-fold increase in abundance since the early 1970s. This study aims to gain understanding of the underlying population dynamics of spiny dogfish, and the possible changes of some critical life-history parameters through time, that might explain the overall increasing trend in abundance. The first step consisted of estimating the abundance of the different life-stages of the population. The pre-adult female, adult male and adult female life-stages were identified and decomposed from length frequency modes. Area was then used for stratification of the log-transformed abundance estimates of each life-stage. MULTIFAN was used to assess differences in the growth of juvenile spiny dogfish. The growth rate was shown to increase from 1968-1971 to 1976-1979 and then decrease to 1988-1990. The hypothesis that these changes were density-dependent was tested and, with the exception of age-2, mean lengths at ages 1 through 5 were significantly correlated with the indices of abundance of the juveniles. Fecundity and size at maturity were also investigated. Literature data from samples collected since 1942 was re-analyzed and compared with more recent data collected during the 1980s and 1991. Significant negative correlations were detected between fecundity and abundance for most size-classes considered, and positive, mostly non-significant correlations were found between fecundity and mean weight. Changes in size at 50% female maturity were also detected and were suggested to be the result of density-dependent changes in juvenile growth. Several recruitment-stock relationships were investigated. Biomass estimates for females were smoothed using an ARIMA time series model on the logarithm of the indices of abundance. A Ricker model, with a temperature-dependent correction, was accepted as the best predictor of recruitment. A Leslie matrix model incorporating density-dependent sub-models for growth, fecundity and recruitment was used to model changes in reproductive dynamics. The model suggested that the observed increase in abundance is at least partially explained by changes in juvenile growth observed during the early-1970s. These changes later resulted in increased mean size at maturity, and subsequent fecundity.

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