Pine trees, mainly Pinus pinaster Aiton, now cover 640,000 ha of the forest occupied surface in Galicia. The possibility of using the residues originating from pine tree exploitation as an alternative energy source could yield to gross benefit around 2.8 x 10(8) euros per year, together with ecological advantages. The object of the present study is the evaluation of the energy contained in these residues through the measurement of their caloric values using a static bomb calorimeter. At the same time, flammabilities were measured by a standard epiradiator thus allowing the calculation of risk indices. This latter is very important to fight and prevent the start and spreading of forest fires. Elementary chemical composition was also determined using an elementary chemical analyser. Biological and bioclimatic parameters, which are very useful for the evaluation of caloric values and flammabilities over the year, were used for discussion of results.