Population ecology of three timber species in Eastern Amazon : implications for management / Ecologia populacional de tres especies madeireiras na Amazonia oriental : implicações para o manejo

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Despite the current and increasing importance of logging in natural forests of the Brazilian Amazon, the population ecology of commercial species is largely unknown. The objective of this study was to contribute to the understanding of the population ecology and the effects of conventional (CL) and reduced impact logging (RIL) on the population dynamics of Lecythis lurida (Lecythidaceae), Pseudopiptadenia psilostachya (Leguminosae) and Chrysophyllum lucentifolium subsp. pachycarpum (Sapotaceae), three commercial tree species, in eastern Amazonia. These species were studied in three plots (24.5 ha each), two of them subjected to logging in 1993 (CL and RIL) and a control plot (CP). All trees 10 cm in diameter at breast height (dbh) were studied between 1993 and 2003, and juveniles (height 30 cm and dbh <10 cm) were sampled in 5.25 ha between 2003 and 2005. Canopy openness was estimated in 2004 using hemispherical photographs. Fruiting was assessed over one reproductive season of L. lurida and P. psilostachya, and three reproductive seasons of C. lucentifolium. Seed germination and the initial growth of P. psilostachya seedlings were assessed in laboratory and shade-house experiments in order to provide information about seedling production. The results highlight the variation in the species ecology and their response to logging. The effects of adopting a single minimum cutting diameter (dbh 50 cm) and of setting aside the same proportion of seed trees (10% of the trees 50 cm dbh) on the proportion of remaining reproductive individuals after harvesting may vary by five-fold among species. P. psilostachya showed characteristics associated with low shade-tolerance and promising potential for management under RIL in 30-year cutting cycles. Given that it is relatively easy to produce seedlings of this species, these seedlings may probably be successfully used in secondary forest enrichment and in the recovery of degraded areas. C. lucentifolium, however, presented a higher shade tolerance and lower potential for management, requiring three-fold longer cutting cycles. Although L. lurida juveniles have an intermediate survival and potential growth rate when compared to the other species, the high frequency of damage to individuals significantly decreases its management potential. The spatial distribution of canopy openness and the population dynamics of the study species indicate the importance of RIL techniques to maintain forest composition and structure. However, results suggest that long cutting cycles and low harvest intensities are necessary in order to achieve both utilization and conservation of forests

ASSUNTO(S)

forest management manejo florestal regeneration (biology) dinamica de vegetação regeneração (biologia) arvores - amazonia vegetation dynamics trees

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