Fire effects and post-fire management on beech forests in the southern Alps.

Fire disturbance in European mountain forests is expected to increase due to global changes. First signs could already be observed during the heat wave in the summer 2003 causing exceptional large fires in beech stands in the southern Alps. Beech is considered a fire sensitive species but post-fire regeneration dynamics are poorly understood and best practices to restore beech forests are missing. To address these issues we implemented a sampling design simulating a chronological sequence from 1970 to 2007 based on 27 burnt sites along the southwestern Alps, which differ in-terms-of fire severity, post-fire-masts and -management. Post-fire canopy cover was related to variables influencing fire intensity and severity, e.g. fire weather indices, topography. Where fire severity was high, canopy opening was immediate and early succession stages were dominated by pioneer species. In moderate severity sites, mortality was progressive and delayed what allowed beech seedling to emerge under intermediate light-conditions and in coincidence with mast years. In managed sites, cutting provided higher beech regeneration right after a mast year, in comparison to unmanaged stands or delayed cuts. Silvicultural measures to restore beech forest after fire should account for the timing of the canopy opening and the time-lag between fire, masting, and cutting.