Establishment and growth of Nothofagus regeneration after selective cutting of a stand in Patagonia, Argentina

Abstract

In 1994, a group selection silvicultural system on a natural forest dominated by Nothofagus dombeyi, N. obliqua, and N. nervosa (Nothofagaceae) was implemented. Age and growth of seedlings (stem height LT < 30 cm, n = 720 plants) and saplings (LT ≥ 30 cm, n = 480) randomly collected in the center and northern periphery of gaps were analysed eight years after treatment. The three species became established simultaneously within the gaps. However, the lower light demanding N. nervosa exhibited a mean age slightly larger given the presence of «advanced regeneration» established previously to cutting implementation. Although immature phases located in the centre of gaps showed an equivalent age than those in the northern periphery, they exhibited a growth rate between 7 and 29% faster probably caused by a greater amount of photosynthetically active radiation. N. dombeyi grew at rates between 13 and 30% slower than the other two species, probably due to the smaller nutrient content of its seeds which would consequently produced less competitive seedlings. Saplings belonged to the same age cohort than seedlings though they grew at rates between 2.6 and 4.8 times faster. The early development of size hierarchy within juvenile trees would be related with the particular morphology and physiology of seeds and plants, and microsite condition.