Changes in woody species composition and structure of Denkoro dry evergreen Afromontane forest over 16 years (2001-2017), South Wollo, Ethiopia

摘要

Conservation of forest ecosystems plays a great role to combat one of the major environmental problems of biodiversity loss. This study was conducted in Denkoro dry evergreen Afromontane forest, south Wollo zone of Amhara National Regional State, Ethiopia to evaluate the changes of woody species composition, structure and regeneration status over 16 years (2001-2017) of conservation effort. Thirty-eight permanent sample plots of 10 m x 50 m size were laid along 50 m altitudinal intervals via nine transect lines which were running parallel to each other for vegetation data collection. Subplots of 2 m x 10 m were laid at two opposite corners of main plots for seedling and sapling inventory. Fifty woody species that belong to 43 genera and 31 families and 59 woody species that belong to 49 genera and 32 families were recorded in 2001 and 2017, respectively. Seventeen new species were registered and eight species were lost in 2017. The density and total basal area of woody species increased from 986 to 1011 individuals ha(-1) and 32.68 to 34.74 m(2) ha(-1), respectively over 16 years. Olinia rochetiana, Olea europaea subsp. cuspidata and Apodytes ditnidiata were the most frequent species in the forest in 2017. Myrsine melartophioes, Olea europaea subsp. cuspidata, Apodytes dimidiata and Olinia rochetiana were the most ecologically important woody species with higher important value index over the studied period (2001-2017). The overall population structure of woody species showed that the forest is under good recruitment potential in both assessments. The numbers of medium DBH class individuals increased in 2017. Poor recruitment and regeneration were also evident in certain woody species. Though woody species composition, structure and regeneration in Denkoro dry evergreen Afromontane forest improved, the forest needs more attention for further conservation and management efforts.