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Growth and productivity of four indigenous tree species (Miliciaexcelsa, Afzeliaquanzensis, Darbegiamelanoxylon and Khayaanthotheca) was evaluated in 23 year old rectangular 400 m2 (20 x 20 m) plots planted at Tanzania Tree Seed Agency (TTSA) Arboretum in Morogoro, Tanzania. Data was collected on survival, diameter at breast height (Dbh), total height, stem form and wood basic density. A t-test of the collected data (dbh, total height and wood basic density) have shown that there were significant (P = 0.05) differences in Dbh and total height. The survival (untransformed) ranged from 93.75% (Afzelia quanzensis) to 100% (M. excelsa, D. melanoxylon and K. anthotheca). K. anthothecawas better with mean Dbh of 32.25 cm and BA of 36.48 m2ha-1than the rest of the species. K. anthotheca attained mean height of 28.09 m and MAI of 1.221 myr-1 followed by A. quanzensis, M. excelsa and the least was D. melanoxylon with mean height of 9.4 m and MAI of 0.413 myr-1. The expected mean yield ranged from 402.6 m3ha-1 (K.anthotheca) to 123.8 m3ha-1 (D.melanoxylon) and MAI ranged from 5.38 m3ha-1 year-1 (D. melanoxylon) to 17.50 m3ha-1year-1(Khaya anthotheca).A. quanzensishad the poorest rank in stem form (12.5% of the trees with crooked stems) followed by D. melanoxylon and K. anthotheca whileM. excelsa was better in form. Though there were no significant (P>0.05) differences in wood basic density, the species differed markedly and D. melanoxylonhad the highest basic density (423.5 kgm-3) while K. anthotheca had the lowest (329.4 kgm-3). Overall,K. anthothecahad better performance (survival and growth) compared to the other species. However as a way of broadening the availability of indigenous species and based on their economic values,all the assessed species showed good performance and all shouldbe considered for further studies and planting in a small scale. |
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