Managers of deciduous perennial fruit crops must consider both biological and economic relationships in determining orchard design and life-time orchard management strategies. Orchardists require a good understanding of the many environmental, physiological and horticultural factors that influence tree growth, fruit production and fruit quality. Of particular importance in apple-tree management is knowledge of how the growing environment and horticultural manipulation of past years affect current and future growth habits and productivity of the tree. In addition to understanding biological factors that influence apple-tree productivity, a diverse range of orchard systems are currently available to orchardists. Each system, consisting of a particular combination of cultivar, rootstock, tree spacing and training method, has implications for fruit quality, quantity and ultimately profit. A dynamic simulation model of apple orchard production is developed in this research, and used to investigate a range of issues of relevance to the commercial apple orchardist. The model is developed in a bioeconomic framework and consists of biophysical and economic components. The biophysical component describes the vegetative and reproductive physiology of an apple tree, factors affecting the quantity and quality of apples produced and interrelationships between these factors. The economic component describes the costs and revenues associated with each orchard system from planting to maturity.

Green Power schemes offer electricity generated by recently constructed renewable energy sources to customers for a higher price than ordinary electricity. This study examines the place of Green Power in the electricity supply industry and among policies to counter global warming, the demand and supply characteristics of Green Power, its effectiveness and measures which could increase its sales. Although growing rapidly, Green Power sales are less than 0.5% of total electricity sales in Australia. The wide variation in market penetration between jurisdictions and between countries for Green Power, the discrepancies between stated willingness-to-pay surveys and actual sales and the low awareness of Green Power found by surveys indicate that Green Power sales could be increased by appropriate marketing and government policies. A sample of 250 pooled time series and cross sectional observations was used to estimate a statistically significant elasticity of demand for residential customers for Green Power with respect to price of -0.96. Green Power schemes appear not to be necessarily loss-making activities for retailers. There has been ample generating capacity for Green Power to meet the growing sales to customers to date. The most cost effective means to increase sales was found to be advertising campaigns such as the campaign in Victoria in 2005. It was also found that full tax deductibility of the Green Power premium to residential customers, an exemption of the Green Power premium from the Goods and Services Tax and a tax rebate for Green Power are probably less cost-effective for promoting sales than direct government purchase of Green Power in terms of cost of policy per unit of increased sales. Green Power plays a small but important role as one amongst a number of climate change policies and the potential of this role is yet to be fully realised.

The objective of this study was to develop an appropriate analytical model for identifying an efficient level of exploitation of the inland fishery resource in South Sumatra, Indonesia. This study involved the evaluation of the existing status of fish stock and assessment of various possible policies for the fishery. The main problem for the inland fishery in South Sumatra is the tendency for the resource to be over-fished, which has been well recognised as shown by some overall indicators, such as virtual disappearance of certain important species and continuous reduction in the size of harvested fish. These problems indicate that proper management is required. This was approached by formulating an analytical framework which includes biological, economic and social aspects of the fishery. Using the biological surplus production model, a bioeconomic model for the inland fishery was developed. Based on the models of Gordon-Schaefer, Gordon-Fox and Copes, supply models for the fishery were estimated. Demand for freshwater fish in the region was assumed to be perfectly elastic. Primary data were used to describe recent cost of fishing effort. Secondary data, combined with results of analysis of primary data, were used to derive a supply function for the fishery. Given available data, and in order to satisfy the requirements for applying the selected model, different types of fishing gear were standardised into a single fishing unit and mixed species of harvested fish were treated as an aggregated fish stock.

A model of a production externality between two industries facing price uncertainty is specified and a Pigouvian tax introduced and solved using First-Order Conditions (FOC). This solution is then used as a baseline for comparison with results for the level of tax found using an Evolutionary Algorithm (EA) where government, as the policy setter, is facing political pressure in the selective environment of the electorate. It is found in the EA solution that if a government faces political pressure in an uncertain economic environment then the settings for the tax may reflect political caution rather than community preferences.

A simplified version of the BEAM Rubber Agroforestry Model is embedded in a dynamic economic model to examine the impact of uncertainty about prices and climate on decision variables. Solutions, in terms of optimal levels for decision variables are found using a Monte Carlo stochastic framework. These solutions were used to derive risk-efficient frontiers corresponding to different levels of the decision variables. The results underline the importance of including uncertainty in dynamic bioeconomic systems since profits under uncertainty turned out to be quite different from those obtained with prices and climate assumed to be constant.

This thesis is concerned with determining the potential of weather derivatives as a weather risk management tool for Australian wheat farmers. The research is intended to provide the fledgling Australian weather derivative market and the Australian agricultural industry with indications of their potential for weather risk management. It provides information to agricultural producers on their usefulness, as well as providing information to Australian banks and other underwriters as they attempt to establish weather derivatives in their current risk transfer portfolios. A review of the weather derivatives literature is presented, followed by research on different areas of weather derivative use by Australian farmers. The applications of this research focus on wheat producers in New South Wales and southern Queensland in the wheat-sheep belt; and provides a basis for further analysis of weather derivatives in other Australian agricultural industries.

This thesis describes the development of a bioeconomic model for estimation of the optimal level of exploitation for banana prawns ('Penaeus merguiensis') in the Gulf of Carpentaria, which is part of the Northern Prawn Fishery in Australia. The model is used to identify optimal levels of effort and catch to achieve sustainable and profitable exploitation. The main contribution of this work is the combination of methods used to model the fishery, which differs from other prawn fisheries in several respects, including their life and migration cycle and their aggregating behaviour. A stage-population matrix is developed to represent population growth and recruitment. The model is calibrated based on 18 years of daily catch data from logbooks and evolutionary algorithms are used to estimate unobservable parameters and to optimise management of the fishery.