Environmental variables and tree population structures in deciduous forests of Central Brazil with different levels of logging

摘要

Population structures of six tree species in three fragments of intact seasonal deciduous forest and three fragments disturbed by logging were studied in the northeastern Goias. Forty random 400 m(2) plots were allocated in each fragment to survey plant population structures, number of stumps, cattle feces, burnt logs, and canopy openness. Soil cover by life forms was estimated in 1m(2) sub-plots. Lianas were abundant in intermediately logged fragments and invasive herbs in the most disturbed fragment. Cattle avoided dense herbaceous strata, such as liana tangles. Cavanillesia arborea, Eugenia dysenterica and Swartzia multijuga trees occurred at very low densities in all the fragments and their seedlings were practically absent, which might endanger their future populations in these fragments. Myracrodruon urundeuva, Tabebuia impetiginosa and Astronium fraxinifolium, the most logged species, had high density of seedlings in all the fragments. However, the highest density of saplings and juvenile individuals occurred in the most disturbed fragment.