Management of mixed forest has become an adaptation strategy to reduce the risks related to climate change. At the same time, ecological models can be a useful tool for studying the growth and productivity of these stands. This work introduces an assessment of the capacity of the 'FORECAST Climate' hybrid model to simulate water stress and productivity in mixed Scots pine and beech forests in Navarre (northern Spain), and their interaction with different levels of regeneration density. The study included three climate scenarios to test the model capacity to simulate water flows under climate change conditions. Model estimations of water deficit and biomass accumulation were sensitive to the reduction in the initial regeneration density rates. The results indicated that the model shows sufficient capacity to simulate the effects of competition between species on tree mortality in mixedwoods, and to estimate the variables related to water flows. On the one hand, the most significant effects of stand density on water availability occur during the first stage of development, while on the other hand, water stress is greater in the case of beech, although the reduction in competition could offset this increase. The implications of this work for adaptive management of mixed forests suggest applying density control soon in order to have significant cumulative effects in coming decades. 

DOI: 10.7818/ECOS.2017.26-2.05