Decision makers often do not adapt as fast as it should be, in order to expect for the overt changing economic conditions. This is also the case of the conversion of agricultural land into short rotation woody crops. Several explanatory approaches are currently discussed in order to explain this behavior. A relatively known explanatory approach is given by the Monte Carlo simulation. This approach utilizes a stochastic comprehensive dynamic model that combines the uncertainty of the investments through probability distribution functions of variables which are important. By means of site-specific conditions and different scenarios, a full economic assessment for short rotation plantations for energy is provided. The financial feasibility for plantations of Eucalyptus globulus stablished in densities of 5000, 7500, 10000 and 15000 tress ha^-1 was determined in four sites. Results indicate that woody crops became profitable in one sites, and only under intensive silviculture. The most profitable species was E. globulus with 5,000 trees ha^-1 in sandy soils. If the conditions for short rotation commercial plantations were improved, it is recommended to incorporate enough and efficient subsidies to this type of woody crops.

Key words: short rotation woody crops, bioenergy, economic evaluation, Monte Carlo, uncertainty.