Deforestation effects on vegetative regeneration and soil quality in tropical semi‐evergreen degraded and protected forests of Bangladesh

Abstract

AbstractTropical forests of the world are degrading at an alarming rate because of human‐induced activities. This study was conducted to determine the consequences of deforestation on the natural regeneration of vegetation and soil quality in tropical, semi‐evergreen protected and degraded forest ecosystems of Bangladesh. In each forest ecosystem, 20 matured trees were randomly selected for laid‐out experimental plots by placing the tree stand at the center of the plot. The number of vegetative species, height, basal area, crown percentages and species richness were measured. The selected soil properties were determined. The vegetation in the protected forest site was denser with an abundance of species than in the degraded forest site. The primary forest regenerative species were dominated by the dipterocarps in both forest sites. The most alarming difference was that of an abrupt decline in regenerative forest species accompanied by an increase in exotic shrubs, grasses and vines typical of open habitats in the degraded forest site. These shrubs (e.g. Melastaoma, Lantana camara, Clerodendrum infortunatum and Jasminium spp.) and grasses and vines (e.g. Imperata cylindrica, Imperata arundinacea, Mikania scandenes, Saccharum spontaneum and Eupatorium odoratum) are gradually replacing the primary forest regenerative species in the degraded forest site. The soil quality of the degraded forest site has deteriorated over time due to preferential removal of finer particles and organic matter by accelerated water erosion. As a result, natural regeneration of primary forest species, especially dipterocarps, is severely affected by the direct effects of biotic interferences and attendant processes of soil quality degradation from deforestation. In contrast, degraded forest sites under regular protection have shown slow, but gradual, increase in crown frequency, enhanced recruitment and recovery of primary forest species, species abundance, and an improvement in soil quality. Copyright © 2001 John Wiley & Sons, Ltd.