Resumen de Does the overstory composition influence on natural regeneration? the case of mixed stone pine and maritime pineforest
Mixing of complementary tree species, such as those formed by stone pine (Pinus pinea L.) and maritime pine (Pinus pinaster Ait) can be used to mitigate the damage inflicted by climate change,whose influence is having an important impact on Mediterranean forests. Long-term stability of mixed stands depends largely on the potential effect that different species have on natural regeneration dynamics. The analysis of the spatial variability in natural regeneration in function of different drivers - such as overstory is crucial for improving the knowledge of the dynamics of mixed Mediterranean forests. For this study, we have used 1936 plots of 0.02 ha established in a mixed forest of stone pine and maritime pine in the Northern Plateau of Spain. Plots were installed immediately following shelterwood cuttings, and the establishment and survivalofseedlings and saplings was annually monitored from 2005 to 2015. Natural regeneration of each species was classified into four different categories (C1, C2, C3 and C4); C4 being the most viable and durable, and C1 the least. Our findings show that it exist an important problem as far as natural regeneration is concerned, especially in P.pinaster natural regeneration, as 17% of the plots have never showed natural regeneration (79% where we observed plots without P.pinasternatural regeneration). Spatial variability was greater in both species for the C1 and C2 categories, those less viable, than for the C3 and C4 categories. Besides, it’s observed a strong association between the natural regeneration and the presence of conspecific adult tree, being more important this association in P.pinaster that in P.pinea. To be able to determinate the spatial variability is essential to develop future studies that analyze patterns of establishment and survival of natural regeneration in mixed forest, which are needed to develop appropriatemanagement strategies.
