Population survey of Milicia excelsa, Pouteria adolfi-fridercii, Antiaris toxicaria and Prunus africana in south and south-western Ethiopia: implications for domesticating and establishing Seed Production Areas

Abstract

The population dynamics and genetic qualities of stem height and dbh of the populations of Milicia excelsa, Pouteria adolfi-fridercii, Antiaris toxicaria and Prunus africana were assessed and studied in 14 forest ecosystems in south and south-western Ethiopia. A systematic random quadrat sampling technique was employed to identify potential habitat area for selected timber species in south and south-western Ethiopia. So, a total of 10 parallel transect lines were set out across each forest habitat. Milicia excelsa was assessed in four forest ecosystems; Bebeka -Duduka natural forest (45 tree stem ha-1) and Yayu coffee mixed forest (40 tree stem ha-1) appeared to have relatively denser population of M. excelsa compared to the other pilot forests. Similarly, statistically larger stem height (m) is observed in Bebeka-Duduka natural forest (x̅=29.5, SD=4.2) and larger dbh size (cm) in Bebeka 1 coffee mixed forest (x̅=48.5, SD=25.2) at p<0.05. Hence, Bebeka-Duduka natural forest and Bebeka 1 coffee mixed forests are identified for in-situ SPA establishment project of the target species. Pouteria adolfi-fridercii was assessed in eight forest ecosystems; Masha-Gora shewi forest appeared to have dense population of P. adolfi-fridercii (150 tree stem ha-1) followed by Bebeka-Kebereta (80 tree stem ha-1) as compared to the remaining pilot forests. However, statistically larger stem height (m) is scored in Bebeka 2 natural forest (x̅=30.6, SD=2.98) and Bebeka-kebereta forest (x̅=30.0, SD=4.4) and larger dbh size (cm) in Bebeka 2 natural forest (x̅=96.5, SD=19.9) at p<0.05. So, Bebeka 2 natural forest and Bebeka-kebereta forest are identified for SPA establishment project of the target species. Antiaris toxicaria was assessed in two forest ecosystems where both forest habitats appeared to have the same density of Antiaris toxicaria in hectare. Moreover, analyses of mean stem height (cm) of Bebeka 1 forest (x̅=21.4, SD=5.2) and Bebeka-kebereta forest (x̅=22.4, SD=2.7), and mean dbh size (cm) of Bebeka 1 forest (x̅=48, SD=16.4) and Bebeka-kebereta forest (x̅=48, SD=8.2) appeared to have not significantly different at p<0.05. Prunus africana was assessed in five forest ecosystems; Masha-Gora shewi forest appeared to have dense population of Prunus africana (150 tree stem ha-1) followed by Kaho-shemeta forest (130 tree stem ha-1) as compared to the remaining pilot forests. However, statistically larger stem height (m) is scored in Kaho-shemeta natural forest (x̅=31, SD=7.6) and larger dbh (cm) in Masha-Gora shewi forest (x̅=64.7, SD=28.2) at p<0.05. As the result, Kaho-shemeta natural forest and Bonga-Teja-adela forest are identified for establishment of seed production area of the target species in-situ. Hence, while implementing the project of domestication and seed production area establishment in south and south-western Ethiopia, in-situ and ex-situ areas must be selected and delineated in accordance with this preliminary information of the population dynamics and genetic qualities of stem height and diameter at breast height. The survey data generated in this study would bridge the research gap in relation to the population status of the target tree species in the designated area.