SURVIVAL AND GROWTH OF NAUCLEA DIDERRICHII AND PERICOPSIS ELATA IN MONOCULTURE AND MIXED-SPECIES PLOTS IN GHANA

Nauclea diderrichii and Pericopsis elata are valuable timber species which are attacked by Orygmophora mediofoveata and Lamprosema lateritialis respectively in plantations. This study was carried out to evaluate the effects of mixed-species planting on survival and growth of these species. The two species (N. diderrichii and P. elata) and three other species (Albizia adianthifolia, Terminalia superba and Tetrapleura tetraptera) were planted in various mixtures. Their survival and growth were monitored for 60 months. Generally, survival and growth performance of P. elata and N. diderrichii were not affected by planting schemes. Trees of both species grew as well in monocultures as they did in mixed stands. Block effect had impact on survival of P. elata and height growth of N. diderrichii. This indicated the importance of local site variability on survival and growth of the two species. While no significant differences in survival and growth were recorded between monoculture and mixed stands of the two timber species, the socio-economic and ecological advantages of mixtures provide sufficient justification to encourage mixed-species plantations.