Tree Growth & Structure

This section will demonstrate how the principles governing tree growth and development determine pruning and training decisions in an orchard. The idea that removing branches from a tree every year will result in improved crop production seems counterintuitive and raises several questions:

? If fruit develops from flowers on tree branches, why does removing branches improve crop production?

? Pruning trees by hand is time consuming and expensive because it requires carefully selecting and cutting branches. How are growers able to maintain profitable businesses when they pay substantial amounts of money to reduce the size of their trees?

To understand these apparent conundrums of pruning and crop production, it is necessary to have both a solid understanding of tree biology, and the essential goals of pruning and training fruit and nut tree species. The general goals of pruning and training include:

• Maximize light interception by leaves and fruit
• Reinvigorate vegetative growth and stimulate renewal of fruit bearing wood
• Optimize the tradeoff between fruit size and number and moderate alternate bearing
• Minimize the impacts of pests and infection by pathogens
• Train tree canopy to facilitate hand, or mechanical, harvesting

The pruning and training techniques used to achieve each goal vary widely among tree crop species. Pruning is a dynamic process influenced by many factors including genetic variation among crops and cultivars in bearing habit and vigor, and environmental factors at a specific site (for example, climate and soil attributes). A solid foundation in the basic biology of tree growth and structure is necessary to balance the many factors influencing tree growth and to make informed pruning decisions throughout the lifespan of an orchard. This section of the website covers basic tree biology and growth necessary to understand how, and why, to prune a tree.