Improvement Cuttings in the Conversion of Pyrenean Oak (Quercus pyrenaica Willd.) Coppice

An appropriate management and valuation of Pyrenean oak (Quercus pyrenaica Willd.) forests are essential in order to ensure their multiple functions and uses. Many coppice forests of Pyrenean oak have been converted into high forests mostly due to changing demands. This work presents a 20-year study conducted with Pyrenean oak coppices, providing results from an experimental trial where silvicultural improvement interventions for coppice conversion were applied. In addition to control, selective thinning and 3-strip thinning with 2 x 2 m, 3 x 3 m, and 3 x 6 m (the latter also included selective thinning) were examined. The study analyzed tree growth, vertical stratification dynamics, and epicormic branching. It was found that the silvicultural interventions promoted tree development differently according to social crown class. The results have shown a significantly different response in tree diameter growth and live crown length, while height growth has been less accentuated. The study also examined the temporal effect of the interventions on diameter growth. Changes in tree crown position and structural characteristics varied among the cutting interventions. Regarding epicormic branching, the results have revealed that the number of shoots does not differ significantly among the treatments but shows differences in length. Management issues regarding Pyrenean oak coppice conversion have also been addressed.