Water Week

EWN Publishing

Fertiliser application computer model for radiata pine forests increases both the yield and profitability of wood production

Posted by waterweek on 26 September 2007

The findings from a major study into applying fertiliser to radiata pine forests have been used to create a computer model that helps forest managers increase both the yield and profitability of wood production, according to Dr Barrie May.

Maximising production and profit: The decision support system had been developed by scientists from Ensis funded by the Forests and Wood Products Research and Development Corporation (FWPRDC) in collaboration with Auspine, Forestry SA and Green Triangle Forest Products. It was based on data from experiments carried out over 12 years at 16 sites in the Green Triangle region in South Australia and Victoria. The computer model integrated the results from these experiments to predict the growth response and profitability of different rates, forms and application scenarios for nitrogen and phosphorous fertiliser. The goal was to help forest managers maximise wood production or profit.

Simple use underpinned by scientific rigour: While simple to use, the system was underpinned by a detailed scientific understanding of the key processes influencing soil nutrient supply and how this drives tree growth. Inputs for the model included basic information such as stocking, age, volume and site quality while outputs included graphs of annual or cumulative response, harvest yield, actual and discounted fertiliser costs and indications of harvest revenues. Results from the research underpinning the new computer model found that growth over six years on plots fertilised with both nitrogen and phosphorous increased by 8 to 28 m3 ha-1, compared with unfertilised plots. An economic analysis showed that this translated to returns on investment ranging from -2 per cent to 39 per cent as a result of the increase in tree size which, in turn, boosted both the volume and unit value of the wood produced.

Improving application afficiency: “The findings show how the efficiency and profitability of fertiliser application can be improved by targeting the most responsive sites and tailoring fertiliser strategies to suit requirements of specific stands,” Dr May says. For example, he says, applying nitrogen to stands previously fertilised with phosphorous increased the average stand value by almost double compared with applying nitrogen (N) alone to unfertilised stands. The findings have also shown that most sites in the Green Triangle do not respond to phosphorous (P) alone and there is little benefit in applying P more frequently than once every ten years at most sites.

Reference: Primary Contact, Dr Barrie May, Experimental Scientist, Ensis. Phone: +61 8 8724 2992. Alt Phone: +61 4 2849 2161. Fax: 61 8 8724 2996. Email: Barrie.May@csiro.au

Erisk Net, 23/9/2007


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