Using soil and climatic data to estimate the performance of trees, carbon sequestration and recharge potential at the catchment scale

There is considerable interest in integrating deep-rooted perennial plants into the dryland farming systems of southern Australia as soil, water supplies and biodiversity are continually threatened by salinity. In addition to wood products, trees could provide new products, such as bioenergy, environmental services, such as the sequestration of carbon, reductions in recharge to groundwater and biodiversity protection. Before marketing these services, it is necessary to determine the optimal distribution of trees across the landscape, in terms of land suitability, their productivity, and proximity to existing processing and transport infrastructure. Similarly, understanding how recharge varies across landscapes will allow the targeting of trees to areas where they are most needed for salinity control. Catchment scale (1:100000) soil and landform datasets are now available across much of the agricultural area of Australia. While these data are at a scale inappropriate for management at the enterprise (farm) scale, they will allow broad planning for new plant-based industries, such as whether there is sufficient suitable land available before embarking on a new enterprise and the likely productivity of that land. In this paper, we outline an approach that combines existing soil and landform data with estimates of climate to produce estimates of likely wood yield, carbon sequestration and potential for recharge to groundwater. Using the 283686 ha Collie catchment of southwestern Australia as an example, this analysis indicated broad areas where land is suitable for forestry, where forestry is unlikely to succeed, or where it was not required because leakage to groundwater is negligible. It also provides broad estimates of wood production and carbon sequestration. The approach is applicable to the integration of deep-rooted perennial plants into farming systems in other regions confronted with multiple natural resource management issue