Logging and topographic effects on tree community structure and habitat associations in a tropical upland evergreen forest,Ghana

We determined the response of tree community structure to logging disturbance and topography,and the patterns of tree-habitat associations in Tano Offin Forest Reserve,Ghana.We sampled trees in 27 20 m× 20 m plots randomly and equally distributed in three topographic habitats(slope,valley,and hilltop) in each of two forests:logged and unlogged.Two topographic features,altitude and degree of slope,were measured and related with species composition.Overall,there were significant effects of logging and topographic habitat and their interaction on species diversity and composition,with the unlogged forest and valley habitat supporting higher diversity.Tree diversity varied among the topographic habitats in the logged but not in the unlogged forest.There were topographic effects on abundance of individual species but not on tree community abundance and basal area.Logging and its interaction with topographic habitat showed significant effects on tree abundance and basal area.Some species were associated with specific topographic habitats or a combination in the logged and unlogged forests.However,the patterns of habitat associations of the species differed between the logged and unlogged forests.

Impacts of forest management on liana diversity and community structure in a tropical forest in Ghana:implications for conservation

We studied the impacts of liana cutting as a forest management tool on liana diversity （species richness, Shannon diversity index） and community structure （diam- eter distribution, basal area, species dominance） in the Asenanyo Forest Reserve, Ghana. Two types of silvicul- turally treated forests were studied： Logging treated （LT） and Tropical Shelterwood System （TSS） treated forests. An untreated primary forest was included as a control, result- ing in three forest management systems. Lianas with diameter 〉2 cm were identified in ten 40 × 40 m2 plots within each management system. Liana cutting signifi- cantly reduced liana species richness, Shannon diversity index, and basal area in the LT forest after two decades. However, liana species richness and basal area werecomparable in the TSS treated and untreated forests, indi- cating significant recovery in the former after over six decades. Sφrensen similarity index of liana species com- position between the untreated forest and each of the treated forests was moderate. Our findings suggest that liana cutting most likely influenced the dominance of some liana species. In view of the adverse impact of blanket liana cutting on liana diversity, selective liana cutting is rec- ommended as a means of controlling liana numbers while maintaining liana diversity.