<p> Policy makers face complex situations involving the analysis and weighting of multiple incentives that complicate the design of natural resource and environmental policy. The objective of this dissertation is to characterize policy makers' incentives, and to investigate the consequences of those incentives on environmental and economic outcomes in the context of wildfire management and environmental policy. </p><p> Wildfire management occurs in a dynamic uncertain environment and requires the coordination of multiple management levels throughout the course of a fire season. Over the course of a wildfire, management teams allocate response resources between suppression of fire growth and protection of valuable assets to mitigate damage with minimal regard for cost. I develop a model of wildfire resource allocation to show that 1) wildfire managers face the incentive to protect residential structures at the expense of larger and more costly fires, and 2) response resources are transferred to fires with more threatened structures constraining the set of resources available to manage other fires in the region. I find empirical evidence to support the predictions of this model with theoretically consistent regression models of wildfire duration, size, and cost using data from U.S. wildfires that occurred between 2001 and 2010. These results imply that continued housing development of wildland prone to wildfire will 1) further distort management incentives, 2) lead to larger and more expensive fires, and 3) provide support for fees on rural homeowners. </p><p> Governments facing political opposition to renewable energy subsidies may resort to augmenting the fixed cost of entry in order to induce environmental outcomes. In global markets, one government's entry policy creates either positive or negative pecuniary externalities in other regions. I develop a two-region model to investigate the behavior of rival governments setting strategic entry policy, and the subsequent impacts on welfare. The results indicate that competition between the rival governments prevents the social optimal level of entry and suggests a role for international environmental agreements.</p>

Foresters can easily calculate the volume and the specific composition of any stand in Lithuania at the moment. To receive the monetary evaluation of the clear cut we need to do continuous measurement of the clear cut, to calculate the volumes of the individual tree species, and then to apply the prices of not truncated forest. The price is determined by specific composition of the stand, the density, the height of the trees, the average diameter. All these factors are mostly influenced by growing location. The purpose of the research is to sift the profitability of the Ld growing location, fir-woods, birch-woods, aspen-woods and oak-woods, evaluating the costs of planting, supervision of the young-woods and cultivation, and assessing the income, expected to receive from these stands. The tasks: 1. To evaluate the specific composition and the other factors of the reproducible stands in the Ld growing location, in Pakruojis forestry. 2. To calculate the costs, related with the reforesting and supervision of these stands. 3. To evaluate the received income from the stands of single tree species of Ld growing location in Pakruojis forestry. 4. To make an analysis of profitability of the stands for the individual species of the trees, in consideration of felling turnover and administration costs. 5. The research object. The forests of the IV group of Pakruojis forestry. The forest-management project of Pakruojis forestry. Reforestation projects in 2001-2003, the data of the... [to full text]

The prairie and bordering woodlands of the Armand Bayou Nature Center, Harris County, Texas were sampled as an example of Texas Upper Coastal Prairie. The prairie is homogeneous and species-rich but shows very low dominance. Paspalum plicatulum, Dichanthelium spp., Carex cherokeensis, Andropogon virginicus, and Schizachyrium scoparium are the dominant graminoids. This prairie resembles the typical Upper Coastal Prairie of Texas but contains a greater number of eastern species with few southern or southwestern influences. Baccharis halimifolia has invaded the prairie and prairie climax species are no longer dominant. There is little evidence of a reduction in diversity due to brush encroachment. The woodlands are an oak and elm dominated riparian forest of the Upper Coastal Prairie with an important shrub component. Quercus phellos, Q. falcata, Ulmus americana, U. alata and U. crassifolia are common canopy species. Ilex vomitoria, Viburnum dentata, Callicarpa americana and Ligustrum sinense are the dominant shrubs.

A mixed pine-oak stand in the Turkey Creek Unit of the Big Thicket National Preserve was logged in 1929-1930 and has experienced no fires since at least 1974. Stand basal area, density, and species richness increased from 1980-1993. A stage projection of the longleaf pine population at the site indicates the population will slowly decline ($\lambda$ = 0.9957) after an initial increase in population size as the population approaches stable size class distribution. Survivorship in the largest size class, 50+ cm dbh, had the largest effect on the outcome. Variations on the base model with potential stronger negative effects from fire suppression reduced $\lambda$ only slightly. Alternatively, small changes in demographic characteristics reflecting positive effects of fire raised $\lambda$ above 1.00. The modeling results suggest that the population is resilient to long-term unfavorable conditions because of the longevity of individual trees.

The development of forest-based biorefineries has the potential to both provide a source of sustainable, low carbon fuel and increase the value drawn from wood residues to help revitalize the forest sector. There has been significant progress toward developing forest biorefining technologies, supported to some extent through government programs, though there are still several barriers to development. Realization of commercial-scale facilities however, will likely be limited by logistical constraints associated with maintaining a consistent supply of woody feedstock and the high capital cost of constructing the facility. To address this issue, mill clusters with sufficient processing capacity were located and evaluated for their suitability to house a forest biorefinery. Existing single-entity mill clusters in Canada were identified according to a set of criteria, and provide the basis for the analysis to determine feedstock supply costs and potential availability. The optimal biorefinery sites within each cluster were identified using a transportation module developed for this study and evaluated according to other factors that would affect the suitability of the site for a large scale forest biorefinery, such as access to markets, other available feedstocks and energy sources. There were four mill clusters identified in eastern Canada that have the potential to support a commercial forest biorefinery. A facility that is centrally located within one of the identified clusters would expect to have a feedstock cost ranging from approximately $95 to $110 per odt. A series of key informant interviews were carried out to further assess the cluster approach to forest biorefinery development. Interviewees generally agreed that the identified locations could potentially support a commercial biorefinery and suggested there are currently significant volumes of underutilized wood in these regions. Forest biorefinery development in the cluster regions, especially where there is mixed forest, should be further pursued. / Thesis (Master, Geography) -- Queen's University, 2013-12-30 17:39:57.326

This thesis describes the modelling of electrohydraulic actuation systems of a prototype forestry vehicle, the experimental identification of the dynamic models parameters and control strategies for forestry operations. / The linear graph method is selected to derive comprehensive models of three electrohydraulic actuation subsystems, i.e. the swing, boom and stick subsystems, on the vehicle based on modelling of individual components. A new approach is proposed, then, to integrate rigid-body dynamic models with the actuator dynamic models to result in a complete machine model. / Off-line parameter identification procedures are used, including the least-square method. A series of experiments is performed to obtain numerical values for the parameters involved in the system models. The experimental setups are described in detail and new procedures are explained. The model validation studies show that the mathematical models closely represent the dynamic characteristics of the forestry machine. / The concept of coordinated control in teleoperation is studied. The resolved motion rate control strategy shows superiority over conventional joint-based control in heavy-duty forestry machines. Two inverse Jacobian manipulator control schemes, based on velocity and on position servo schemes, are introduced and evaluated under various operating conditions. The results provide guidelines for the design and implementation of manipulator controllers on a forestry machine.

No description available.

Recently, robotic technology has begun to play an important role in forestry operations. An important class of forestry machines is comprised of systems equipped with a mobile platform fitted with an articulated arm carrying a tree processing head. The dynamics of such systems are needed for simulation and control purposes. In contrast to conventional industrial manipulators, which are mounted on stationary bases, a mobile manipulator is dynamically coupled with its base. Base compliance, non-linearity and coupled dynamics result in positioning inaccuracies which in turn give rise to control problems. / The dynamics of the FERIC forwarder forestry machine including its compliant tires were developed and implemented symbolically in compact form with the help of an iterative Newton-Euler dynamic formulation. Various models with increasing complexity were derived. Based on a simplified dynamics model, a valve-sizing methodology was developed and used to size hydraulic proportional valves of the machine's actuators. / System parameters have been obtained by various methods, including use of blueprints, weighing, solid modeling and various experiments. A set-point feedforward controller was designed and the machine's responses for various inputs were obtained to analyze the dynamic behavior of the system. Although initial simulations were done in Matlab and Simulink, C programs were developed for increased speed of execution. In addition, techniques to minimize computation time have been developed and applied to result in almost real time simulation.

Eucalyptus grandis was introduced into South Africa in the 19th century, and has since become the most important of the hardwood plantation tree species grown for pulp. Until the late 1980's E. grandis was virtually the only eucalypt species grown. In order to meet the increasing demand for pulpwood in South Africa, forestry companies need to increase their timber output from an existing land base (Brown and Hillis, 1984; Kimmins, 1994 and Little and Gardner, 2003), or alternatively extend the planting of favourable alternative tree species into areas previously considered unsuitable for forestry due to unfavourable climatic conditions. From 1984 the major timber companies expanded their plantation forestry into the colder, frost-prone highland areas of western KwaZulu-Natal, the northeastern Cape and southeastern Mpumalanga Highveld. As E. grandis was not tolerant to severe frost, E. macarthurii amd E. nitens were planted in these areas as alternatives (Schonau and Gardner, 1991). As much of the earlier research had been centered around the development of silvicultural standards for E. grandis, it became necessary to test these for the different eucalypt species. Two trials were therefore established to E. marcarthurii and E. nitens with the following objectives: - to extend current recommendations to include different species, - to determine the degree of interaction between different silvicultural standards (genetic improvement, fertilisation and weed control), - to determine the effects of weeds, fertilisation, genotype and regeneration method (seedling vs coppicing) on the initial and long term growth, uniformity, tree straightness and survival of cold tolerant eucalypts, - cost effectiveness of various methods for re-establishing E. nitens and E. macarthurii. Genetic improvement played an important role in the establishment and initial growth of E. macarthurii and E. nitens. The improved treatments outperformed the unimproved treatments in terms of tree growth until canopy closure. At the last measured date when the trees were six years of age, the E. nitens improved seedlings were still significantly better in terms of basal area when compared to unimproved seedlings. The initial positive effect of genetic improvement of E. macarthurii seedling however, was not sustained. Genetic improvement of E. macarthurii and E. nitens also had a positive effect on tree straightness and survival when the trees were assessed at five years of age. The genetic improvement of both species also showed to be a viable option to produce an optimum timber output at a lower cost when regeneration is carried out by means of replanting with seedlings. Fertilisation also showed positive effects in terms of the establishment and initial growth of E. macarthurii and E. nitens. At six years after planting, the basal area of E. macarthurii seedlings without fertiliser was still significantly lower than any one of the other treatments. However, the initial positive effect fertiliser had on the growth of E. nitens seedlings decreased to a non-significant level at six years after planting. Fertilisation of E. macarthurii and E. nitens had a positive effect on tree straightness and survival when the trees were assessed at five years of age. The fertilisation of E. macarthurii seedlings also produced an adequate amount of timber at a relatively low cost. The controlling of weeds did not have an impact on tree performance initially or after canopy closure for either E. macarthurii or E. nitens. This is due to the lack of weed growth at these high altitudes at which the sites were planted. Little and Schumann (1996) found that eucalypts could tolerate an aboveground weed biomass of up to 2000 kg ha (-1) before there were any severe losses in growth due to competition. At both these trials, the weed load did not reach these levels in order to compete with the trees. No significant interactions between any of the treatments were detected at both these sites at any stage. At the last measured date, there were no significant differences in terms of tree growth between the coppice and seedling treatments for either E. macarthurii or E. nitens. Regeneration by means of E. macarthurii and E. nitens coppice had a positive effect on tree straightness and survival when the trees were assessed at five years of age. Re-establishment by means of coppice for both E. macarthurii and E. nitens was also shown to be by far the most cost-effective way at present to produce an adequate amount of timber. Coppicing was shown to be the least costly way to produce a m2 ha(-1) of timber provided the right species are coppiced, and optimum density levels are obtained. / Thesis (M.Sc.Agric.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

In the soil, mercury species are predominantly associated with particulate organic carbon (POC) and can be exported with surface runoff by erosion or in solution, associated with dissolved organic carbon (DOC). / Water column samples collected in September 1997 and May 1998 from three treatment groups of lakes (9 whose watershed was clear-cut, 9 whose watershed was burnt, and 20 control lakes, whose watershed forests have not been touched by forest fires or clear-cutting for at least 70 years) were analyzed. Results of these analyses reveal a significant increase in the DOC and dissolved methylmercury concentrations in lake water after watershed clear-cutting. Following forest fires, there is an enrichment of methylmercury in the suspended particulate matter (SPM), as well as significant losses of nitrogen species. Thus, watershed perturbations increase the export of mercury species from the catchment to drainage lakes, and this effect is greater in logged- than in burnt-watershed lakes. This mercury export is dependent on the delivery of POC and DOC to the lakes, which increases as a result of surface runoff intensification. (Abstract shortened by UMI.)