Executive Summary
What the report is about
This research developed the AGGRO model as a tool to support farm forestry development. A cutdown version of the model has since been incorporated into the Farm Forestry Toolbox (available from www.privateforests.tas.gov.au).

Who is the report targeted at?
While the AGGRO model itself passes on a wealth of information to small growers about indicative yields for a range of farm forestry scenarios, informed by the many valuable silvicultural experiments conducted in Australia, the detailed science presented in this report informs researchers and scientists with an interest in the technical details underpinning model development.

Background
The AGGRO model was developed through this research in recognition that models used in industrial forestry are not well suited to farm forestry situations, which typically fail to predict growth realistically and do not account for silvicultural management, like thinning and pruning. The model is informed by a significant body of information collected from silvicultural experiments conducted throughout Australia. It provides farm foresters and researchers with more reliable information to guide tree planting and management.

Aims/Objectives
The primary objective of this study was the development of a user-friendly PC package (the AGGRO model) for the prediction of wood volume for a range of planting designs (including wide-spaced and strip plantings) and thinning of Eucalyptus globulus and E. nitens given only a few simple and easily obtained site descriptors. The model developed also predicts branch biomass and average tree size and so gives some indication of end product suitability.

Methods used
Field work and analysis were undertaken to better define the physiological and growth response of plantation grown Eucalyptus globulus trees to wide-spacing. This information was then used to underpin AGGRO, a simple, easy-to-use predictive model within an Excel spreadsheet format. This model was subsequently verified for growth predictions of E. globulus and E. nitens.

Results/Key findings
The AGGRO model is a powerful tool that encapsulates not only the knowledge generated in this report, but years of research by many scientists. It puts at the fingertips of the farm forester a powerful scenario generation tool.

The major outcomes of the model predictions are reported according to:

• impact of spacing on growth and form
• patterns of light interception by tree crowns
• nitrogen distribution in tree crowns
• spacing effects on nitrogen and photosynthesis
• modelling production
• implications for farm forestry.

Implications for relevant stakeholders
The research outlines the types of question that can be explored and how silvicultural regimes and planting layouts can be tailored to site characteristics. The detailed physiological and mensurational work in this project has developed a considerable knowledge base on the responses of photosynthetic and morphological traits. This information is inevitably complex. However, the work has shown that by embedding this knowledge into a simple-to-use decision support system, the implications of this research can become accessible to end-users.

Recommendations
This project recommended the incorporation of AGGRO into the Farm Forestry Toolbox, which includes an economic evaluation tool. Together, these tools will enable farm foresters to evaluate the economic consequences of plantation project development and management options on their lands with greater confidence. An agreement between JVAP and the Cooperative Research Centre for Sustainable Production Forestry and Private Forests Tasmania was reached at the conclusion of this project, and a cutdown version of AGGRO has now been incorporated in Version 6 of the Farm Forestry Toolbox.