An economic evaluation of alternative genetic improvement strategies for farm woodland trees

A cost-benefit analysis (CBA), focusing on the Net Present Value (NPV) of a current genetic improvement programme for broadleaved trees was performed using Monte Carlo simulation, with an add-on software package ('@RISK') specifically designed to take account of the uncertainty associated with long-term projects. The CBA was undertaken by evaluating the total cost of achieving a given estimated genetic gain via each of the breeding strategies considered. The estimated values of genetic gain were then expressed in terms of the increased value of timber output. Cash flows were based on current estimated tree establishment costs and anticipated productivity of the four tree species included in the programme (ash, Fraxinus excelsior; sycamore, Acer pseudoplatanus; wild cherry, Prunus avium; and sweet chestnut, Castanea sativa), when grown primarily for a timber crop. The results of the NPV analysis indicated that tree improvement could be cost-effective for small genetic gains, but that current breeding strategies differed markedly in their cost-effectiveness. Improvement scenarios based on conventional selection and testing techniques, such as simple mass selection and recurrent selection (seed orchards), were found to be the most cost-effective at a discount rate of 6 per cent. In contrast, tree improvement scenarios based on clonal techniques consistently ranked lowest, despite the much higher genetic gains achieved. The use of clonal techniques was found to be particularly hard to justify with broadleaved tree species of relatively low timber value. Overall, with the current state of broadleaved timber markets in the UK, and the current areas being planted, investment in basic genetic improvement of high-value timber species appears financially worth while. The estimated direct additional financial benefit to growers, if new planting is undertaken with improved stock as opposed to unimproved stock, is estimated to range from 38 pounds ha-1 with Simple Mass Selection to 100 pounds ha-1 with Simple Recurrent Selection.