Growth performance of different multipurpose tree and shrub western species at Bako, Oromia

A multipurpose tree and shrub (MPTS) screening experiment was conducted at Bako Agricultural Research Centre, western Oromia for four consecutive years (1992/93-1995/96). The objective of the study was to assess the growth performance and adaptation of different tree and shrub species to the area depending on their early growth patterns and survival. This is a sort of matching the trees with the Bako environment. In this experiment, 10 different multipurpose tree and shrub species (Markhamia lutea, Calliandra calothyrsus, Chamacytisus palmensis, Erythrina brucei, E. abyssinica, Acacia cyanophila, A. mearnsii, Moringa oleifera and A. Melanoxylon) were included, and compared by using randomized complete block design with two replications. Results showed that there was a significant difference in height growth (P less than or equal to 0.01), root collar diameter (P less than or equal to 0.05) and survival (P less than or equal to 0.05) between the different tree and shrub species at this particular area. This could be due to the environmental factors and inherent genetic potentials of the species which generally govern tree growth. Of the trees tested, A. mearnsii performed better than the other species with respect to height growth (9.61 m). There was no significant difference between A. Mearnsii (19.85 cm) and C. calothyrsus (19.10 cm) regarding root collar diameter development, but both of them surprised the others in girth growth. Of all species, Markhamia lutea, Albizia gummifera, Acacia mearnsii and Calliandra calothyrsus showed good survival rates with mean values of 98, 94, 84 and 74%, respectively. Comparatively lower survival rate of C. calothyrsus was due to browsing by wild animals. Base on the results of four-year data, the growth performance of these tree species is promising and hence they can be considered for further technology specific and on-farm agroforestry works around Bako.