An assessment of forest responses to silvicultural interventions in tropical moist forest in Ghana
This study examines the effects, 40 y later, of silvicultural interventions on forest structure, stand productivity and composition and diversity of species in Bobiri Forest Reserve in Ghana. Data were gathered from stands treated under three silvicultural systems: the Tropical Shelterwood System (TSS), the Post-exploitation System (PES) and the Girth Limit Selection System with post-harvest refinement (GLS), along with comparative data from unlogged (UNL) forest. Forty years later, the treated stands were structurally similar 40 to unlogged forest, although stem densities were higher in the former relative to the latter. Six dominant families of species were common to both treated and unlogged forest. Species richness and diversity were higher in PES, GLS and UNL forest relative to TSS forest. In contrast to unlogged forest where shade tolerant species were dominant, non-pioneer light-demanders were dominant in the treated stands. Liana densities were similar in the different types of treated forest but higher in unlogged forest. The numbers of commercial species were not different between treated and unlogged forest, although whereas >50% of species in TSS forest were commercial, >50% of species in PES, GLS and UNL forest were non-commercial species. Additionally, the densities of commercial stems were about twice higher in TSS and PES relative to unlogged forest. Total standing volumes of crop trees DBH>30 cm in GLS (∼349 m 3 ha-1) and TSS (308 m3 ha-1 ) were comparable to ∼251 m3 ha-1 in unlogged forest but higher relative to ∼242 m3 ha -1 in PES. The desirable commercial species contributed >50% of total standing volume of crop trees in TSS and PES forest but <40% in GLS and unlogged forest. Also, there was better representation of good quality commercial stems in treated forest relative to unlogged forest.