Growth, mortality, and recruitment of tree species in an Amazonian rainforest over 13 years of reduced impact logging

Abstract

Forest harvesting causes disturbances in the forest, affecting the dynamics of tree species. In this study, growth, mortality, and recruitment of trees ≥45 cm DBH were assessed in different forests logged along 13 years (2002–2015) in the Eastern Amazon. The data were collected in a control unlogged forest and in four 100-ha working units divided into 20 plots of 5 ha (total of 100 plots in 500 ha sampled) and inventoried at 100% one year before harvesting and again in 2015. A total of 49 species were analyzed in the study. The highest mortality rate occurred in the first five years after harvesting (5.6%), with a reduction from the seventh year (3.2% year−1), a period in which recruitment rate significantly increased for species from all ecological groups. Harvesting reduced both the number of individuals and species in the first five years after logging. Logged areas presented the highest growth rates five and seven years and only stabilized eleven years after logging. Within the range of 3–40 m3 ha−1 of logging intensity no differences were observed in growth rates of remaining trees ≥45 cm DBH. Pioneer, light-demanding, and shade-tolerant species presented higher growth rates in the first five years after logging. From seven years after harvesting, light-demanding presented a higher growth when compared to the shade-tolerant species. Larger diameter classes presented the highest relative growth rates (RGR). All diameter classes increased RGR up to 11 years after logging.