98 The Potential Contribution of Irish State Forests to the Supply of Energy R. McCARTHY and R. M. KEOGH Forest and Wildlife Service. Site Productivity and Biomass Section, Crop Structure and Biometrics Section. SUMMARY This paper estimates what the energy-supply of a hypothetical conventional State forest of 360,000 ha would be if it were totally composed of Sitka spruce, Yield Class 14 on a rotation of 50 years. The data base is small and results are, therefore. tentative. Nevertheless, it appears that a large forest estate might be able to supply an equivalent amount of energy as used by its potentially dependent forest industries. Whilst the annual supply of energy to the total national budget appears to be modest , the long term contribution would be accumulative because of the renewable nature of the source. It is felt that two aspects should now be examined: (1) the role dry matter might have in the country's forests. as an alternative measure to volume alone and (2) the approach research should adopt in relation to biomass investigations. INTRODUCTION When fossil fuel energy is cheap and abundant, the search for alternative sources of power tends to be less active than in periods when it is expensive or scarce. Supply deficits have been experienced on a large scale during the Second World War which produced many innovations to overcome them. Between 1974 and 1982 the world suffered dramatic price increases in crude oil that were followed by the establishment of programmes to create alternative power sources. Ireland has experienced all of these trends and may be on the verge of a period of relatively cheap and abundant fossil fuel, if indications about finds materialise into commercially productive oil wells. Does this mean that research related to renewable power SOurces will become less important in the near future? Hopefully not. Fossil fuel deposits have a limited life span which renewable sources of energy would help to extend. In the long term future, the world is likely to be forced to shift its dependency from non renewable sources to alternatives as the former are depleted. The sooner this transition is prepared for, the easier will be the changeover. IRISH FORESTRY, 1983, Vol. 40, No.2: 98-109.