Population Structure and Regeneration Status of Woody Species in Kenech Forest, Southwest Ethiopia

Abstract

Understanding the structural pattern and regeneration status of tree species is an important measure taken to assess the vegetation dynamics and their destruction factors species as well as management history and ecology of the forest. This study was conducted with the objective to assess the species diversity, structure, and regeneration status of woody species in Kenech natural forest, Ethiopia. Systematic random sampling method was employed as a sampling design for the collection of vegetation data. Accordingly, 40 plots of 20 m × 20 m were laid at every 100 m along four parallel transect lines following altitudinal gradient. Any woody species of trees and shrubs with the diameter at breast height (DBH) ≥2.5 cm was measured at 1.5 m from the ground. In each sample plots, all woody species seedling, sapling, and mature woody species were counted and recorded. A total of 80 plant species categorized into 67 genera and 28 families were recorded and identified, for description and analysis of vegetation structure. Structural analysis of the Kenech natural forest revealed a density of 840 stems/ha and a total basal area of 56.8 m2/ha. About 80.36% of the individuals are found in the first two classes (2.5–10 and 10–20 cm). The general pattern of DBH class distribution of woody species in the study area revealed an inverted J shape indicating the presence of a high density of trees in the lower DBH class than in the higher. The most dominant tree species relatively with the highest importance values recorded in the area were Pouteria adolfi-friedericii, Podocarpus falcatus, Celtis africana, Mimusops kummel, Pyschotria orophila, and Olea capensis subsp. macrocarpa. Forty-two species (64.61%) were represented by both seedling and sapling class, whereas 9 species (13.84%) were not regenerating.

Woody species diversity and carbon stock of church forests along age gradient in Dangila district, Awi-zone, Ethiopia

“…The general pattern of DBH and height class distribution of church forests in Dangila district showed an inverted J-shaped (Figure 4A & B). This was similar with Tara Gedam church forest (Zegeye et al, 2011); Kuandisha forest (Berhanu et al, 2016); Debre Libanos church forest ( Hordofa et al, 2020) and Kenech Forest (Balemlay and Siraj, 2021). The DBH class distribution of woody species along age gradient also had an inverted J-shape (Figure 5A -C).…”

“…The distribution pattern indicates the general trends of population dynamics and recruitment processes. A species with the highest number of individuals in the lower DBH classes suggests that they had good regeneration potential and vice versa ( Zegeye et al., 2011 ; Balemlay and Siraj, 2021 ). The average distribution of seedlings, saplings and mature tree of the studied church forests were 5023, 7026 and 1925 individuals/ha respectively ( Table 6 ).…”

Woody Species Diversity, Composition, and Regeneration Status of Abbo Sacred Forest, Southern Ethiopia

“…The ratio of the density of trees and shrubs with DBH >10 cm to DBH >20 cm is taken as a measure of size class distribution. The value of this ratio was 2.02 in Abbo Sacred Forest which is higher than that of some other Afromontane forests in Ethiopia like Agama forest (1.98) [ 44 ], Kenech forest (1.8) [ 33 ], and Majang forest (1.4) [ 46 ], indicating a predominance of small-sized individuals that start to grow following excessive cuttings or other anthropogenic disturbances.…”

“…The regeneration status of Abbo Sacred Forest was computed by comparing the density data of seedlings and saplings with those of matured trees following the techniques described in [ 33 , 34 ]. It was categorized as “good” regeneration if seedlings > saplings > mature trees; “fair” regeneration, if mature trees > saplings > seedlings; “poor” regeneration, if the species survives only in the sapling stage (saplings less than, more than, or equal to mature trees) with no seedlings; and “no” regeneration if the species is absent in both seedling and sapling stage but present as a mature tree.…”

Conversion of natural forests to farmlands and its associated woody species diversity and carbon stocks in a span of 33 years (1984 to 2016): in the case of southwestern Ethiopia

“…Three transects with a total of 30 plots (10 plots on each transect) were established on NF, FFI, and FL using a compass and a geographic positioning system (GPS). A distance of 200 meters (m) separated the transect lines and sample plots from each other 13,14 (Figure 4). Each land use system's sample plot size was selected based on the expected density of woody species 15,16 .…”