The intent of this thesis is to apply policy design analysis to federal forest policy in the United States. This thesis describes alternative policy analysis frameworks and argues that a policy design approach is the most useful for analyzing federal forest policy and for understanding the intense social conflict which surrounds forest policy today. This paper will argue that present conflicts stem from the inability of past forest policy designs to simultaneously pursue the important social goals of economic development, ecological sustainability and social democracy. What is needed is an approach to forest policy which can address and ameliorate these conflicts. This will require several changes in the underlying assumptions of natural resource management. Ecosystem management, as an alternative approach to forest policy, will be discussed and analyzed in order to identify in what ways forest policy may change and to speculate about the implications of these changes.

Water chemistry (carbon dioxide, pH, alkalinity, hardness, and turbidity) and physical habitat (depth, velocity and substrate) change gradually on the Little Colorado River, Arizona, downstream from Blue Springs (river kilometer 11.40 to 21.06). Fish distribution is correlated with changes in water chemistry and physical habitat. Monthly trends in water chemistry and physical habitat depended upon seasonal conditions: summer rain runoff (July and September 1992), spring runoff (April 1993), and base flow (June and July 1993).

<p> Landscape-scale forest restoration treatments are planned for four national forests in Northern Arizona: the Coconino, Kaibab, Tonto, and Apache-Sitgreaves National Forests. The first analysis area comprises 900,000 acres on the Coconino and Kaibab National Forests where the U.S. Forest Service is proposing restoration activities on approximately 600,000 acres over a ten year period pending acceptance of an Environmental Impact Statement. These forest restoration treatments are intended to accomplish a number of objectives including reducing the threat of catastrophic wild fire and subsequent flooding and to restore forest health, function, and resiliency. Previous studies suggest that in semi-arid, ponderosa pine watersheds there was a possibility to increase surface water yields 15-40% when basal area was reduced by 30-100%. Because of these results, there is considerable interest in the amount of increased water yield that may recharge from these activities. </p><p> The objectives of this study were to 1) examine the state of knowledge of forest restoration thinning and its hydrological responses and to evaluate the quality and type of related references that exist within the literature and 2) simulate possible changes in recharge and aquifer response following forest restoration treatments and climate change. A systematic review process following the guidelines suggested by the Collaboration for Environmental Evidence was conducted to examine literature relevant to this topic. The Northern Arizona Regional Groundwater-Flow Model was used to simulate the changes expected from forest restoration treatments and climate change. </p><p> The systematic review returned 37 references that were used to answer questions regarding tree removal and the associated hydrological responses. Data from individual studies suggest that forest treatments that reduce tree density tend to increase surface water yield and groundwater recharge while reducing evapotranspiration. On average, there was a 0-50% increase in surface water yield when 5-100% of a watershed was treated. Groundwater results were less conclusive and there was no overall correlation for all studies between percent area treated and groundwater recharge. A majority of studies (33 of 37) reported statistically significant results, either as increases in water yield, decreases in evapotranspiration, or increases in groundwater table elevation. Results are highly variable, and diminish within five to ten years for water yield increases and even quicker (&lt; 4 years) for groundwater table heights. </p><p> Using a groundwater-flow model, it was estimated that over the ten-year period of forest restoration treatment there was a 2.8% increase in annual recharge to aquifers in the Verde Valley compared to conditions that existed in 2000-2005. However, these increases were assumed to quickly decline after treatment due to regrowth of vegetation and forest underbrush. Furthermore, estimated increases in groundwater recharge were masked by decreases in water levels, stream baseflow, and groundwater storage resulting from surface water diversions and groundwater pumping. These results should be used in conjunction with other data such as those recovered from paired-watershed studies to help guide decision-making with respect to groundwater supply and demand issues, operations, and balancing the needs of both natural and human communities. </p>

<p> Six transgenic events (TEv) of <i>Castanea dentata,</i> each containing four to five transgenes with varying insertion numbers, were field-tested for non-target impacts on root symbiotic ectomycorrhizal fungi (EMF). Also included was the cloned plant used to create the TEv as a control, and a variety of seed-grown <i>C. dentata</i> and other <i>Castanea</i> species or hybrids to test natural variation and the effect of micropropagation procedures. The field sites included two open-field and two shelterwood sites. Two of the six TEv, both containing the transgene encoding the antimicrobial peptide ESF39, formed significantly less ectomycorrhizas than the control in their first season in the field; no differences were detected in the next season. No other differences in receptivity to EMF or between EMF communities were detected among the various experimental plants. No significant impacts on EMF of the transgenes encoding oxalate oxidase, GFP, BAR and NPTII were detected. Nor were impacts due to differences in insert copy number, insert position or micropropagation procedures. The shelterwood sites had significantly higher colonization than both of the open-field sites. Both open sites had relatively low diversity and communities composed of EMF typically found in pioneer communities. One of the shelterwood sites had significantly higher diversity and EMF typical of mature forest communities. The other did not; possible reasons for this are discussed. This study compared experimental plants with high numbers of gene inserts, differences found did not correlate with the number of insertion events or genes used, indicating that pleiotropic effects are rare in this species. Differences in colonization were temporally dependent which should be considered in future studies. Site characteristics affected both colonization by and community composition of EMF.</p>

<p> The accurate estimation of forest attributes at many different spatial scales is a critical problem. Forest landowners may be interested in estimating timber volume, forest biomass, and forest structure to determine their forest's condition and value. Counties and states may be interested to learn about their forests to develop sustainable management plans and policies related to forests, wildlife, and climate change. Countries and consortiums of countries need information about their forests to set global and national targets to deal with issues of climate change and deforestation as well as to set national targets and understand the state of their forest at a given point in time. </p><p> This dissertation approaches these questions from two perspectives. The first perspective uses the process model Biome-BGC paired with inventory and remote sensing data to make inferences about a current forest state given known climate and site variables. Using a model of this type, future climate data can be used to make predictions about future forest states as well. An example of this work applied to a forest in northern California is presented. The second perspective of estimating forest attributes uses high resolution aerial imagery paired with light detection and ranging (LiDAR) remote sensing data to develop statistical estimates of forest structure. Two approaches within this perspective are presented: a pixel based approach and an object based approach. Both approaches can serve as the platform on which models (either empirical growth and yield models or process models) can be run to generate inferences about future forest state and current forest biogeochemical cycling.</p>

<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>

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.

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.

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.