Les difficultés de régénération naturelle des pessières subalpines: prédation des graines au sol et blocages dus à l'humus

Abstract

The subalpine spruce forest is characterized by deficient natural regeneration. To determine which factors were detrimental to the installation and growth of young saplings, experimental seedlings were sown at different sites (Adenostylo alliariae-Piceetum and Homogyno-Piceetum) in the northwestern Alps (table I). Combinations of several types of treatment in the seed beds allowed determination of the optimal conditions for installation and establishment of the most favourable ecological conditions for seedling survival Predation by rodents and humic parameters (aluminium level) were found to restrict seed germination (table II). The latter factor was also responsible for an important loss of plantlets (at least 50%) after the first year (table II).