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.