Southern Forests: a Journal of Forest Science

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.

The Brazilian Cerrado is a heterogeneous ecosystem where annual woody-layer litter production shows strong spatiotemporal variation. Although Cerrado litter dynamics have been well-documented in forest physiognomies, knowledge from savanna habitats remains limited despite their predominance across the landscape. In this study, the fine-woody litter production and their fractions were quantified throughout the year in an area covered by the cerrado denso physiognomy (a woodland savanna) at Panga Ecological Reserve, Minas Gerais, Brazil. Using ten litter traps distributed along a 250 m transect, it was estimated that 4.44 Mg ha-1 of litter was produced annually in the cerrado denso, with leaves representing the greatest fraction (75.9%), followed by small woods (11.9%), reproductive parts (8.8%) and miscellaneous items (3.4%). Litterfall varied strongly throughout the year (monthly range: 0.17 to 1.01 Mg ha-1), and although the contribution of different fractions also varied monthly, leaves were dominant through most of the year (range: 34-94%). In fact, there was a strong positive relationship between leaf-litter biomass and the total amount of litter produced. The estimate falls within the previously recorded litter production range for the Cerrado and corresponds numerically to the position occupied by the cerrado denso physiognomy in the structural vegetation gradient in this biome. Furthermore, results indicated that litterfall in this physiognomy is strongly seasonal. Leaves represented the major part of accumulated biomass and were responsible for the increased dry season production when most woody species concentrated their leaf shedding. These results aid the understanding of the functioning of Cerrado ecosystems, and determining litterfall patterns for the entire vegetation mosaic of physiognomies is essential for the implementation of quantifiable environmental quality diagnoses and evaluations of anthropic impacts.

Four community-managed Sal forests in Dadeldhura district of Nepal were selected for the assessment of carbon stock. The stratified random sampling method was applied to measure the field data from 105 sample plots of 100 m2. The carbon stock of trees and shrubs was estimated using Chave allometric equations for moist forests. The study found that the community forests stored carbon stock ranging from 148.5 to 202.3 Mg ha-1 (mean: 175.5 Mg ha-1). The community forests managed for a longer duration have higher carbon stock than the community forests managed for a shorter duration. From the study, it can be concluded that these forests have been acting as a storehouse of the carbon. So, we can infer that community management has had a positive impact on increasing the carbon stock of forests and thus on the mitigation of global climate change. This study contributes to the understanding of the role of community forests in mitigating the effects of global climate change.