Stand structure, regeneration and seed dispersal patterns of Nothofagus glauca (Hualo) in central Chile

Abstract

Growing interest in functional silviculture is promoting new approaches to the study of seed dispersal and regeneration, two of the key processes that determine the structure and dynamics of plant populations. Nothofagus glauca is an obligate-seeding tree species typical of Mediterranean forests in central Chile. We studied stand structure, regeneration, seed release (quantity and quality) and seed dispersal in stands of N. glauca. Seed release started in mid- to late summer or in early autumn, and continued for a period of four to five months. Seed release reached a number of up to 2 million seeds per hectare. Seed shadow was characterised by a peak of density beneath the plant canopy and a very short tail of much lower densities, indicating that seeds are concentrated beneath mother plants when dispersed. The number of individuals who produced seeds during the season was estimated at 100 trees per hectare, and the highest frequency of seeding trees was observed in the diameter class of 28 cm to 48 cm, with the highest production of seeds in the 43 cm individuals (70 years old). Ninety percent of the regeneration was concentrated within the seed tree crown radius. Only a marginal presence of seedlings was observed outside the crown projection area and decreased as the distance to the base of the tree increased, until reaching a maximum distance of 12 m. It can be concluded that adult N. glauca forests rarely disturbed, tend to form
multi-age stand structures.

Keywords: spatiotemporal variation; recruitment limitation; silviculture, coppice system, Nothofagus