Structure and floristic composition of a tropical evergreen forest in south-west India

Abstract

A permanent plot of 28 ha was established in a dense wet evergreen forest in the Western Ghats of India to study the functioning of the ecosystem. Since April 1990, 1981 trees of ≥30 cm gbh have been enumerated in a systematic sampling of five strips totalling 3.12 ha. This paper describes the main structural and floristic characteristics of the plot.The density (635 trees ≥30 cm gbh per hectare) and basal area (39.7 m2 ha−1) are high. Despite the high diversity (Simpson's D = 0.92 and Shannon's H' = 4.56), four species are distinctly, dominant in terms of an importance value index (relative density + relative basal area). Each of these four species occupies a different layer in the ecosystem: Humboldtia brunonis Wall. (Fabaceae) dominates the undergrowth, Myristica dactyloïdes Gaertn. (Myristicaceae) the intermediate strata, Valeria indica L. (Dipterocarpaceae) the higher canopy level and Dipterocarpus indicus Bedd. (Dipterocarpaceae) the emergents. This pronounced species hierarchy is one of the most important characteristics of the evergreen forests of the Western Ghats. The two dipterocarps account for 20.1% of the total number of trees and contribute 40.9% to the total basal area. This formation can, therefore, be considered as the westernmost lowland dipterocarp forest of Asia.Analysis of the spatial variations in the floristic composition and in the structure of the main species populations shows that two kinds of mature phases can be identified: where the topography is raised and gently sloping, the vertical structure of the stand is discontinuous, with Dipterocarpus indicus and Vateria indica forming an emergent layer above a dense undergrowth; on slopes, the stand is lower, vertically continuous and saturated with Valeria indica and Myristica dactyloïdes. The link between the structure of the stand and dynamic processes is discussed.

Spatial variation in the structure and floristic composition of "restinga" vegetation in southeastern Brazil

“…Moreover, in our study, the oligarchic structure (the concentration of IV in a few species plus many species of lesser importance) found is also common in tropical forest formations, especially in disturbed or early successional communities (Keel & Prance 1979, Campbell et al 1986, Pascal & Pélissier 1996, and in other open vegetation types marginal to the Atlantic rain forest (Scarano 2002). Nevertheless, diversity (H' = 3.07) is expectedly lower than that of Atlantic (e.g, Sanchez et al 1999) and Amazon rain forests (e.g, Campbell et al 1992), but surprisingly high considering the extreme environmental conditions these plants are often subjected to (e.g., Scarano et al 2005).…”

Análise da florística e estrutura de floresta primária visando a seleção de espécies-chave, através de análise multivariada, para a restauração de áreas mineradas em unidades de conservação

“…A distribuição diamétrica em J invertido é uma característica das florestas primárias multiespecíficas e multiâneas tendo muitos estudos observado esse tipo de distribuição do número de árvores por classes de diâmetros (MEYER, 1952;TAKEUCHI, 1960;RODRIGUES, 1963;UHL;MURPHY, 1981;FABER-LANGERDEON;GENTRY, 1991;PASCAL;PELISSIER, 1996;SCHAAF et al, 2006). Para o platô Saracá, a distribuição diamétrica mostrou o desenho típico de florestas com estrutura primária, apresentando claro padrão de exponencial negativo (Figura 1), ou seja, alta concentração de indivíduos nas classes menores e redução acentuada no sentido das classes maiores (FABER-LANGERDEON;GENTRY, 1991;PASCAL;PELISSIER, 1996).…”

“…Para o platô Saracá, a distribuição diamétrica mostrou o desenho típico de florestas com estrutura primária, apresentando claro padrão de exponencial negativo (Figura 1), ou seja, alta concentração de indivíduos nas classes menores e redução acentuada no sentido das classes maiores (FABER-LANGERDEON;GENTRY, 1991;PASCAL;PELISSIER, 1996).…”

Vegetation structure and floristic composition of Gergeda Anfillo Forest, West Ethiopia

“…Height is a good indicator of the role of species that determines the vertical structure of the stand (Pascal and Pelissier, 1996). Thus, tree that were found in sampling plots were classified into eight height classes.…”