Agroforestry (the integration of trees into agricultural landscapes) has been promoted, in Australia and elsewhere, as a way to increase farm productivity by providing a wide range of benefits. Despite this, adoption of agroforestry in Australian agricultural systems remains low. To implement agroforestry, farmers must be convinced the benefits of including trees outweigh the costs. This review evaluates the available quantitative data on shelter benefits with emphasis on Australian conditions, identifies key research gaps and determines if there is sufficient knowledge to make accurate predictions about impacts on farm productivity.
Availability of quantitative data on windbreak shelter benefits was examined in five key areas; water use and evaporation, crop/pasture production, livestock mortality, livestock productivity and the capacity to model impacts of windbreaks on crop/livestock systems. Good quantitative data exists for many areas, particularly for changes in environmental conditions following tree establishment, however there were many gaps in key areas. Importantly, the ability to predict crop growth under spatially and temporally variable environmental conditions and the impact of windbreaks on livestock productivity is not yet able to be meaningfully quantified. Thus modelling the profitability of windbreaks is difficult and existing models require additional quantitative data to validate and improve them.