Nordpatagonic forest of the Aisén region in meridional Chile (44° 47' south) has been affected by numerous large fires between the years 1936 to 1956. They were produced by pioneers in their attempts to clear out lands for prairies. For that reason the native vegetation was reduced at 50% of the original covering. After a half of century of these impacts, the forest has reached a partial regeneration; however there are some important sectors where this regeneration is poor or null. We begin here the first study of this phenomenon in a Patagonic Andean sub-basinin.