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This article assesses the effect of different logging levels on loss of above-ground biomass and the contribution of different ecological groups of species in the long-term recovery of C stocks. A randomized complete blocks design was established in 1987 with three felling treatments: diameter above 20 cm, 40 cm and 60 cm. All the trees and palms bigger than 10 cm dbh were measured. The average stock in old growth forests was 84.3 t C/ha. Low- and medium-impact treatments led to C reductions in 10% and 44%, respectively; for low impact, a significant increase was detected after the 25-year measurements, which could be related to a possible CO2 fertilization effect. For high impact, 79% of C was lost, but the original level recovered after 20 years. The ecological succession process, subsequent to logging, is an efficient mechanism to restore C stocks. [ABSTRACT FROM AUTHOR]

Nearly all forests in the Venezuelan alluvial plains are converted to agricultural lands. However, in forest reserves, logging is a selective extraction activity that disturbs part of the ecosystem. This work was aimed at studying floristic composition changes over longer periods of time in a forest with different logging intensities. We measured 11 plots distributed in random block design of 1 ha each. The importance value index (IVI) was calculated for all species and was used in a canonical correspondence analysis to evaluate species behaviour. Cecropia peltata and Inga sp. dominated the first successional stage attaining a maximum IVI close to 12 years but showed clear decline thereafter. The next successional phase was dominated by late secondary species such as Triplaris americana and Guazuma ulmifolia. Climax species such as Pouteria reticulata and Pachira quinata showed drastic reduction in importance and very slow recovery. This study was based on 16-year-observation period, a rare work which could make use of such long period of direct observation. Our results could be used to guide ecological restoration in deforested areas. Forest management strategies should be redrawn to make it a sustainable option. [ABSTRACT FROM AUTHOR]