Growth rate of a terra firme rain forest in Brazilian Amazonia over an eight-year period in response to logging

Abstract

This paper deals with growth rates of trees $ 5cm dbh over an eight-year period from 257 species at the Tapajós National Forest. The discussion is centred on the behaviour of the forest after logging. Permanent sample plots were established in 1981 and measured at the first time. The area was logged in 1982. Measurements after logging occurred in 1983, 1987 and 1989. Considering all species together, diameter increment was similar for both intensities of logging until five years after logging. Light-demanding species showed significantly higher growth rates than shade-tolerant species in the logged forest, with greater increment in the heavier treatment intensity. Commercial species also had higher growth rates in the heavier logged area, although those were significantly different only in the period from one to five years after logging. In the undisturbed forest, growth rates increased with increasing dbh size. At species level, growth rate varied between and within treatments, as well as between trees within species, depending mainly on degree of canopy opening. The logging favoured the growth of commercial species, chiefly the light-demanders. Therefore, if the same growth conditions continue being given, for example by silvicultural treatments, to those species of commercial interest, the forest would reach a stock available for harvesting around year 30 after logging. However, the high variation in increment rates indicates that an eight-year period is not sufficient to allow predictions on cutting cycles or polycyclic management systems for the study forest. KEY WORDSAmazonian forest, tree growth rate, diameter increment, forest dynamics, logging.Crescimento de uma floresta de terra firme na Amazônia brasileira em um período de oito anos após a exploração florestal. RESUMO É analisado o crescimento de 257 espécies arbóreas, considerando indivíduos com DAP $ 5cm, na Floresta Nacional do Tapajós, em um período de oito anos. Em 1981 foram estabelecidas parcelas permanentes, e medidas pela primeira vez. Em 1982 a área foi explorada. Medições após a exploração foram realizadas em 1983, 1987 e 1989. Considerando todas as espécies juntas, o incremento em diâmetro foi similar nas duas intensidades de exploração, até o quinto ano após a colheita. As espécies intolerantes à sombra mostraram crescimento significativamente maior do que as espécies tolerantes à sombra na floresta explorada, com maior incremento na área de exploração mais pesada. Espécies comerciais também tiveram crescimento maior nessa mesma intensidade de exploração, embora tenham sido significantemente diferentes apenas entre o primeiro e o quinto ano após a exploração. Na floresta não-explorada, as árvores com diâmetros maiores PALAVRAS-CHAVEFloresta amazônica, crescimento de árvores, incremento diamétrico, dinâmica de florestas, exploração florestal.

SUPERAÇÃO DE DORMÊNCIA EM SEMENTES DE Tachigali myrmecophila (Ducke) Ducke

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Charcoal Production as a Means of Forest Management, Biodiversity Conservation and Livelihood Support in Nepal

“…Diversity measures of understory were significantly higher in the logged forest than that in the unlogged forest after it was performed for 10 years in beech forests of Shafarood in Guilan [21]. Similarly, some commercial and light demanding species showed significantly higher growth rates in the logged forest (treatment applied forest), with greater increment in the heavier treatment intensity [22]. Intensive silviculture treatment had the largest impact on the density and growth rates of the regeneration [23], which is similar to the findings of this study.…”

Pollination biology in Jacaranda copaia (Aubl.) D. Don. (Bignoniaceae) at the "Floresta Nacional do Tapajós", Central Amazon, Brazil

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