Gap phase regeneration of tree species of differing successional status in a humid tropical forest of Kerala, India

Germination, establishment and growth of seedlings of tree species Palaquium ellipticum (primary), Actinodaphne malabarica (late secondary) and Macaranga peltata (early secondary) were studied in a humid tropical forest at Nelliampathy, in the Western Ghats of Kerala. While the primary species completed its germination within a brief period of 1.5 months, at the other extreme, early secondary species showed slow germination extending for about 5 months, the late secondary species falling in between. Although, all the species studied showed higher establishment and growth under gaps, the early secondary species were more responsive compared to the primary species. Primary species showed better establishment in undisturbed sites and natural gaps than under selection felled gaps; the reverse was true for late and early secondary species. Survival of seedlings increased with gap size, but sharply declined with gap age. Shoot/root ratio was consistently higher in the early secondary species than in the primary species

Successional patterns and gap phase dynamics of a humid tropical forest of the Western Ghats of Kerala, India: ground vegetation, biomass, productivity and nutrient cycling

The population dynamics of the ground vegetation and its energetics such as biomass accumulation and net primary productivity, and the nutrient cycling patterns in the humid tropical forest of the Western Ghats in India are largely determined by gap age and by whether gaps are formed naturally or through selection felling. Responses of plant categories such as herbs, shrubs, tree seedlings and saplings also vary depending upon gap type and age. An exotic species such as Chromolaena odorata occurred only in selection-felled gaps ((9 ± 3)-(49 ± 4) individuals (100 m)). Nilgirianthus ciliatus, a dominant shrub, plays a key role in the gaps in determining population dynamics of others. The net primary productivity of the ground vegetation, which is about 31.17 ± 4.26 kg (100 m) year in an undisturbed site, increased a year after gap formation to 102.82 ± 6.46 kg (100 m) year in natural gaps and to 71.82 ± 2.36 kg (100 m) year in selection-felled gaps. Five years after gap formation, net primary productivity of the ground vegetation declined considerably, this being related to decline in fast-growing shrub and secondary tree species in the vegetation and gap closure. A similar trend was also recorded for the rates of nutrient uptake and nutrient accumulation in the vegetation. In natural gaps the soil nutrient level increased gradually with gap age. This could be attributed to slow release of nutrients from the fallen trunks and nutrient storage in the rapidly recovering vegetation. In contrast, in selection-felled gaps, the quantities of soil nutrients such as nitrogen, phosphorus and magnesium were higher in 1-year-old gaps than in undisturbed sites, owing to the release of these nutrients from leaf litter and wood debris which were deposited in larger quantities within the gap itself, and owing to sparse ground vegetation resulting from the greater disturbance of the soil, in the first 1 or 2 years. The fractional annual turnover rates of elements of the ground vegetation and the soil were higher in 1-year-old gaps and declined with gap age. The significance of these results for forest management is discussed

Vegetation and gap dynamics of a tropical wet evergreen forest in the Western Ghats of Kerala, India

The wet evergreen forest of Nelliampathy in the Western Ghats of Kerala in India is a mixed forest with a high species diversity and basal cover. In this relatively undisturbed ecosystem, canopy gaps are largely formed through single tree fall, but gaps through branch fall, crown fall, standing dead trees or multiple tree fall also occur. Canopy gap formation is more (over 82% of the total gaps created) during the monsoon season. The mean number of gaps formed in this forest is 1.13 ha<SUP>-1</SUP> y<SUP>-1</SUP> and the turnover rate is 83 years. The majority of the gaps created (over 70%) are of smaller size (≥ 100 m<SUP>2</SUP>). In this forest, while some top canopy tree species (those capable of exceeding 25 m in height at maturity) such as Palaquium ellipticum and Mesua nagassarium are well represented in seedling, sapling and mature tree stages, others like Aglaia exstipulata and Mastixia arborea are observed only as saplings and/or mature trees with no seedling populations. The possible reasons for these two types of regeneration behaviour by top canopy tree species in the context of canopy gap size and seasonality in gap formation are discussed

Tree species yielding edible fruit in the coffee-based homegardens of Kerala, India: their diversity, uses and management

Cultivated fruit trees, Non-crop fruit trees, Diversity, Coffee-based homegardens,