Economic assessment of windbreaks on the south-eastern coast of Western Australia

Windbreaks in the south-eastern coastal region of Western Australia are generally established to protect agricultural land against damage from wind erosion. However, to date there has been no detailed economic analysis of establishing windbreaks on farms in the region. Accordingly, a decision model was developed to estimate benefits and costs of windbreaks as determined by production inputs and outputs, windbreak system design, frequency and severity of wind damage, and commercial tree products from the windbreak. The model used crop yield responses to shelter at sites across the medium–low rainfall agricultural areas of southern Western Australia. The model lends itself to further development as a risk analysis tool incorporating probabilities and empirical measurements of wind damage. A benefit:cost analysis, using a partial budget approach, compared situations with and without windbreaks. The model showed that windbreaks improved profitability when they reduced the severity of wind damage to crops. Without wind erosion events, windbreaks had a negative impact on farm profit. Investment in windbreaks is therefore a form of insurance. The relative level of benefits is determined by the frequency of wind damage, severity of damage, distance between windbreaks, pruning of lateral tree roots and the possibility of using trees that can produce commercial timber products.