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Protected areas are the most commonly used tool for in situ conservation of biodiversity. Selective removal of species proposed by the local communities living surrounding the national park and grazing pressure negatively affect the composition, structure, and regeneration of woody species. Assessment of vegetation structure and regeneration status of woody species is essential for orienting management activities. The purpose of this study was to investigate the floristic composition, population structure, and regeneration status of woody species in the Loka Abaya National Park, to design conservation strategies. A total of 99, 20 m × 20 m quadrats were systematically laid along an established line transect to collect a list of woody species, abundance, height, and diameter at breast height (DBH), while five 3 m × 3 m subquadrats within the main quadrats were established to assess the regeneration status of woody species. In each quadrat, all woody species were identified, counted, and recorded. In each quadrat, all tree and shrub species higher than ≥2 m in height and ≥2 cm in diameter at breast height were measured by a calibrated wooden stick and by a caliper, respectively. Density, frequency, basal area, importance value index (IVI), height, and diameter at breast height (DBH) were used for description of vegetation structure, while the density of mature trees, saplings, and seedlings was used for assessment of regeneration status of woody species. A total of 101 woody plant species representing 40 families in 69 genera were collected, identified, and documented. Fabaceae was the most diverse family representing 16 (15.84%) species, followed by Euphorbiaceae 9 species (8.91%) and Anacardiaceae with 6 species (5.94%). Four families including Combretaceae, Moraceae, Olacaceae, and Tiliaceae were represented by 4 species each. 4 families were also represented by 3 species each, 12 families were represented by two species each, and 18 families were represented by one species. The density of trees was 831.31 individuals ha−1, while the total basal area was 73.18 m2·ha−1. D. angustifolia, C. molle, E. schimperi, R. natalensis, O. europaea L. subsp. cuspidataD. cinerea, A. brevispica, I. mitis, and E. tirucalli were ecologically important woody species. The majority (75%) of woody plant species had a less than 5% importance value index (IVI). The diameter class distribution of selected tree species demonstrated various patterns of population structure, implying the existence of different population dynamics among ecologically important tree species. The regeneration assessment results demonstrate that 32.35% had poor regeneration, 19.12% had good regeneration, 16.17% had fair regeneration, 8.82% lacked regeneration, and 14.08% appeared as newly regenerated species in the national park. The majority of woody species had a small population size, and some of them were found in specific habitats which need attention for conservation, and those woody species lack regeneration study soil seed bank and propagation methods for sustainable conservation.

Abstract. Ao A, Changkija S, Tripathi SK. 2020. Species diversity, population structure, and regeneration status of trees in Fakim Wildlife Sanctuary, Nagaland, Northeast India. Biodiversitas 21: 2777-2785. The plant species composition and diversity represent the overall health of the forest ecosystems and provide useful insight on forest conservation, and the species regeneration is important in assessing the potential of the forests to serve the society on sustained basis. This present study aimed to assess the species diversity, population structure, and regeneration status of the trees in temperate forest of Fakim Wildlife Sanctuary, Nagaland, Northeast India. Tree species composition, population structure and regeneration status were analyzed by randomly establishing eight plots of 0.1 ha within the sanctuary. Density, basal area, abundance, evenness, and other diversity indices were calculated for mature trees with girth at breast height (GBH) ≥ 30 cm. A total of 60 tree species belonging to 40 genera and 27 families were recorded. The most dominant families recorded were Lauraceae and Rosaceae. The total tree density recorded from the forest was 432.5 individuals ha-1 with a basal area 42.8 m2 ha-1. Cinnamomum zeylanicum and Lithocarpus pachyphyllus had the highest density with 17.58 individuals ha-1 and Lithocarpus pachyphyllus had the highest basal area with 2.64 m2 ha-1. The species with the highest IVI was Betula alnoides (17.13). Girth class of 30-60 cm had the highest density and basal area with 280 individuals ha-1 and 20.7 m2 ha-1. The diversity indices such as Shannon-Wiener index, Simpson index, Pielou evenness index, and Margalef species richness index were 3.90, 0.93, 0.92, and 11.59, respectively in the wildlife sanctuary. The present study showed that 41% of tree species exhibited good regeneration status, 31% as fair regeneration, 8% as poor regeneration and 20% had no regeneration. The present data will be useful to understand the current status of tree species and will serve as baseline information to the forest department, policymakers and conservationists to develop management plans for the conservation of priority species in the area.

Dry evergreen Afromontane forests are severely threatened due to the expansion of agriculture and overgrazing by livestock. The objective of this study was to investigate the composition of woody species, structure, regeneration status and plant communities in Seqela forest, as well as the relationship between plant community types and environmental variables. Systematic sampling was used to collect vegetation and environmental data from 52 (20 m x 20 m) (400 m2) plots. Density, Diameter at Breast Height (DBH), basal area, frequency, and importance value index (IVI) of woody species were computed to characterize the vegetation structure of the forest. Agglomerative hierarchical cluster analysis and Canonical Correspondence Analysis (CCA) with R software were used to identify plant communities and analyse the relationship between plant community types and environmental variables, respectively. A total of 68 woody plant species belonging to 63 genera and 44 families were identified. The Shannon diversity index and evenness values of the study area were 2.12 and 0.92, respectively. The total basal area and density of woody species were 27.4 m2 ha-1 and 1079.3 individual ha-1, respectively. The most frequent woody species in the Seqela forest included Albizia gummifera (51.92%), Croton macrostachyus (44.23%), Olinia rochetiana and Teclea nobilis (36.54%). Additionally, the most dominant species, as indicated by their importance value index (IVI), were Erythrina brucei (IVI = 11.24), Prunus africana (IVI=8.68), and Croton macrostachyus (IVI=7.38). Four plant community types were identified: Albizia gummifera - Ekebergia capensis, Prunus africana - Croton macrostachyus, Vachellia abyssinica - Dombeya torrida and Schefflera abyssinica - Teclea nobilis. The CCA results showed that the variation of species distribution and plant community formation were significantly (P < 0.05) related to altitude, organic matter, aspect, slope and soil available phosphorus. The regeneration status assessment of the forest revealed a good regeneration status, which was linked to diverse and abundant seed bank in the soil can ensure a continuous supply of seeds for regeneration; therefore, it is recommended to implement periodic soil seed bank assessments to monitor seed diversity and abundance and inform targeted conservation actions.

Ethiopia is a biodiversity hotspot area with a high concentration of plant species that play countless roles in ecosystem resilience and mitigating the effects of climate change. However, forest resources are degrading at an alarming rate due to different anthropogenic factors. Pugnido Forest, which is among Ethiopia's greatest woodland sections, also faced a similar challenge. Thus, this study was intended to assess the composition, structure, and regeneration status of woody plant species in Pugnido Forest, West Ethiopia. Eighty main plots sized 20 × 20 m were sampled systematically on six east-west-oriented line transects, which are parallel to each other and 500 m apart. At the four corners and the center of the main plots, five subplots sized 2 m × 2 m were laid to collect seedling and sapling information. Individual woody species were identified and then recorded per plot. The forest structure and regeneration status data were recorded and analyzed using structural parameters. Communities were identified via cluster analysis. A comparison of diversity and composition among communities was made using the Shannon–Wiener diversity and Sorensen's similarity coefficients, respectively. A total of 106 woody species included in 40 families were documented. Fabaceae stands first in the species-rich family (23.6%), and Moraceae stands second (8.5%). Overall Shannon–Wiener diversity and evenness of species were 4.41 and 0.93, respectively. Four communities were generated from cluster analysis. Sorensen's similarity value among communities ranged from 42% to 59%. The forest's density and basal area were 5298.8 stems·ha−1 and 82.5 m2·ha−1, respectively. The trend in frequency and density classes showed a decreasing number of species towards higher classes. Diameter at breast height (DBH), height, and basal area analyses revealed a normal J-shaped pattern. Several species had a smaller importance value index (IVI) value. Density ratios of juveniles to adult plants indicated good regeneration status. Species with small IVI values and few or no seedlings require conservation priority. Top priority must be given to conserving species with low IVI values and few or no seedlings.

Floristic composition, structure and regeneration status of woody plant species in Northwest Ethiopia

Wabero forest is one of the very few remnant moist evergreen montane forests in Southeast Ethiopia. However, basic data on vegetation structure and composition of the forest that could provide valuable information for possible conservation measures is lacking. The main objective of this study, therefore, was to investigate the woody species composition, vegetation structure and regeneration status of the forest. In the study 30 quadrants of 20 m by 20 m were used for woody species data and 5 m by 5 m for sapling and seedling in a nested form. The sample quadrants were laid down along transects at a distance of 300 m from each other. Diameters at breast height (DBH), basal area, frequency and importance value index were used for analysis of vegetation structure. In the study, a total of 47 woody plant species belonging to 43 genera and 33 families were recorded. The major families were Rubiaceae and Rutaceae each represented by four species followed by Sapindaceae, Moraceae and Oleaceae each represented by three species. The rest of the 28 families were represented by one or two species, only. The mean density of all the woody species recorded in the study site was 21,737 ha-1. Diospyros abyssinica, Podocarpus falcatus, Strychnos mitis, Celtis africana and Coffea arabica were found to be the most dominant and frequent species with the highest importance value index. Results of regeneration status of the forest, which was analyzed by comparing number of seedling and sapling with mature trees, revealed that the forest is under good regeneration status. Therefore, based on the results of the study, awareness creation and implementation of participatory forest management strategy is recommended in order to sustain the forest. Key words: Basal area, diameters at breast height (DBH), importance value index, Montane forest, woody species composition.

Dry evergreen Afromontane forests are severely threatened due to the expansion of agriculture and overgrazing by livestock. The objective of this study was to investigate the composition of woody species, structure, regeneration status and plant communities in Seqela forest, as well as the relationship between plant community types and environmental variables. Systematic sampling was used to collect vegetation and environmental data from 52 (20 m x 20 m) (400 m2) plots. Density, Diameter at Breast Height (DBH), basal area, frequency, and importance value index (IVI) of woody species were computed to characterize the vegetation structure of the forest. Agglomerative hierarchical cluster analysis and Canonical Correspondence Analysis (CCA) with R software were used to identify plant communities and analyse the relationship between plant community types and environmental variables, respectively. A total of 68 woody plant species belonging to 63 genera and 44 families were identified. The Shannon diversity index and evenness values of the study area were 2.12 and 0.92, respectively. The total basal area and density of woody species were 27.4 m2 ha−1 and 1079.3 individual ha−1, respectively. The most frequent woody species in the Seqela forest included Albizia gummifera (51.92%), Croton macrostachyus (44.23%), Olinia rochetiana and Teclea nobilis (36.54%). Additionally, the most dominant species, as indicated by their importance value index (IVI), were Erythrina brucei (IVI = 11.24), Prunus africana (IVI=8.68), and Croton macrostachyus (IVI=7.38). Four plant community types were identified: Albizia gummifera - Ekebergia capensis, Prunus africana - Croton macrostachyus, Vachellia abyssinica - Dombeya torrida and Schefflera abyssinica - Teclea nobilis. The CCA results showed that the variation of species distribution and plant community formation were significantly (P < 0.05) related to altitude, organic matter, aspect, slope and soil available phosphorus. The regeneration status assessment of the forest revealed a good regeneration status, which was linked to diverse and abundant seed bank in the soil can ensure a continuous supply of seeds for regeneration; therefore, it is recommended to implement periodic soil seed bank assessments to monitor seed diversity and abundance and inform targeted conservation actions.

Ethiopia's rich ecological landscapes, including its protected areas, are increasingly threatened by deforestation, agricultural encroachment, overgrazing, and climate variability. This study assessed the woody species composition, structure, and regeneration status of Omo National Park, located in southwestern Ethiopia. A total of 97 main plots (20 m × 20 m) for mature trees, 97 subplots (5 m × 5 m) for saplings, and 388 microplots (1 m × 1 m) for seedlings were systematically established. Woody species with a diameter at breast height (DBH) ≥ 2.5 cm and height ≥ 2.5 m were measured. In total, 72 woody species belonging to 51 families and 28 genera were recorded, comprising 39.5% trees, 57.9% shrubs, 1.6% tree/shrub forms, and 0.21% climbers from 950 individual plants. Fabaceae (10 spp.) and Combretaceae (7 spp.) were the most species-rich families. The park exhibited a high Shannon diversity index (3.34) and evenness (0.74), with a mature woody plant density of 244.8 individuals ha⁻¹ and a total basal area of 17.76 m² ha⁻¹. Species frequency declined with increasing DBH and height classes. Seedling and sapling densities were 450 and 411.6 individuals ha⁻¹, respectively, indicating good overall regeneration status. The study highlights the need for targeted monitoring and management of dominant and potentially invasive species to ensure the park's ecological sustainability.

Determining the population structure and regeneration status of woody species in Hereje Natural Forest, Ethiopia, is essential for identifying potential management interventions to mitigate the adverse effects of deforestation and forest degradation. Three parallel transect lines (every 100 m) were established along altitudinal gradients, and 45 plots of 20 m x 20 m were used to collect vegetation data. Living woody species diameter breast height (DBH) was measured in each plot for those with height ≥2 m and DBH ≥ 2.5 cm at about 1.3 m from the ground. For this study seedlings and saplings inventory was made using five subplots of 2 m X 2m, four on each corner of the main plots and one in the center, In this study we have used appropriate formulas to analyze basal area, density, regeneration status and important value index. A total of 44 plant species were identified and classified into 41 genera and 28 families. The most relatively dominant species in the Hereje forest were Syzygium guineense (24.47%), Ficus sur (20%), Combretum molle (18.58%), Croton macrostachyus (18.11%), and Terminalia schimperiana (9.29%). According to this study, the density of tree species in the forest decreases as DBH classes increase. The predominance of small DBH classes is due to the excessive cutting of certain size classes by the local communities, indicating extensive changes in the woody plant diversity and age structure. The result of the study also revealed that diameter and height class distribution showed an inverted J-shape indicating the majority of the species had the highest number of individuals at lower DBH. Maytenus gracilipes has the highest number of seedlings in the study area. However, the overall regeneration status of the study forest was in fair condition. Hence, immediate conservation is required for these species with poor regeneration and least IVI should be given conservation priority.

The study was conducted on Gemechis natural forest, West Hararghe, Oromia Regional state, Ethiopia with the objective of determining the floristic composition, structural analysis and regeneration of wood plant species. Systematic sampling was used to collect vegetation data. Accordingly,50 sampling quadrats of 20 m x 20 m were laid along six line transects at every 50 m interval within which five 5 m x 5 m small quadrats were laied to sample woody species with <2cm DBH (diameter at breast height). In each quadrat, all live woody species were recorded with their number counted and DBH measured for those with DBH>2cm. Fifty one (51) woody species belonging to 50 genera and 34 families were recorded in the forest. The collected specimens were composed of 64.7% of tree, 31.3% shrubs and 3.9% of lianas. The most species rich families were Rosaceae, Lamiaceae and Myrsinaceae. Shannon diversity index and evenness of woody species of the Gemechis natural forest were 3.04 and 0.77, respectively. The total density of woody species recorded in Gemechis forest was 3430 individuals ha -1 . . Total basal area of woody species in the study area was 31.12 m 2 h -1 . The dominant and ecologically most important tree species in Gemechis Forest on the basis of their importance value index( IVI) values were Maesa lanceolata (19.2), Rytigna neglecta (16.9), Maytenus sp. (15.9), Bersama abyssinica (14.2), Argomuellera macrophyllab (11.7), Dovyalis caffra (10.9), Teclea nobilis (9.24) and Vernonia amygdalina (7.3). Cummulative DBH class distribution showed that large number of individuals fall in lower DBH class, which shows that this vegetations is in a good regeneration status. However, as some species are of irregular population structure and low IVI further study should be conducted to identify factors that negatively affect them. In general, the data from this study showed that the forest had high species diversity. From the cummulative DBH class distribution of the study area, the number of individuals that fall in lower DBH classes were higher than their number at higher DBH classes which indicate that seedlings and sapling were more in number than the mature/older woody species which suggesting that vegetation of Gemechis forest was generally in a good regeneration status. Keywords : Basal area, Diameter at breast highest, Gemechis forest, Important value index, Woody species DOI : 10.7176/JBAH/9-1-07

Aims: Quantitative field study was conducted to assess forest regeneration status in ten tropical dry evergreen forest (TDEF) sites at southern Coromandel Coast. Study Design: Quantitative field survey. Place and Duration of Study: Tamil Nadu, One year Methodology: Forest regeneration study was conducted in ten tropical dry evergreen forest sites located on the southern Coromandel Coast. A twenty 10 m × 10 m (100 m2; 0.01 ha) square plots were randomly laid in all forest sites. All encountered plants were identified to species level in the field. Individuals up to the height &lt;20 cm were considered as seedlings, whereas the height classes 20.1-40 cm, 40.1-100 cm, and 100.1-&lt;10 girth at breast height (gbh) cm were considered as saplings. Height class classification followed Induchoodan (1993). Regeneration status of species was identified with density of seedlings, saplings, and adult plants. Five regeneration categories were recognized as in Shankar (2001): 1. Good regeneration: Seedlings &gt; saplings&gt; adults; 2. Fair regeneration: Seedlings &gt; saplings ≥ adults; 3. Poor regeneration: (i) Species survives only as saplings but not as seedlings; (ii) Seedlings &lt; saplings &lt; adults; 4. No regeneration: Species absent both in seedlings and saplings but present as adults; and, 5. New regeneration: Species present only in seedlings or saplings but not as adult trees Results: A total of 51640 seedlings were recorded from ten study sites. Seedling density varied from 1970 to 9050 ha-1. On an average each site had 5163 ± 2507 seedlings ha-1. A sum of 38130 saplings was encountered. Sapling density ha-1 ranged from 1560 to 7670 plants ha-1, while the mean sapling density was recorded as 3813 ± 1954 plants ha-1. Species richness of young plants ha-1 varied from 25 to 33 in study area. The mean species richness of the study area was 28.5 ± 3.20 species ha-1. On average, each mature individual had 11.84 ± 2.94 young plants in the study area. Young-mature plant ratios differed from 7.27 to 14.78. The proportion of species showing good, fair, poor and no regeneration varied considerably among study sites. The present investigation recorded a net loss of 3.11 to 43.78% of seedlings during the seedling-sapling transition stage, and a further loss of 66.44 to 84.4% of saplings in the developmental phase from saplings to trees. The seedling survival rate ranged from 5.61 to 12.10%. Conclusion: The mean young plant density, diversity, and species richness obtained in the recent study are comparable with those of the world’s tropical forests.

This study investigated the composition, structure, and regeneration status of woody species in Gondar Zuria District Qes Diba Botanical Garden under Gondar University Teda Campus. The circular plots with a radius of 6.5 m for a tree, 4.5 m for a sapling, and 2.5 m for a seedling were sampled to determine the regeneration status, species biodiversity, structure of woody species, and species composition in the study area. Diameter at the breast height, an important value index, and the number of seedlings, saplings, and mature tree plant species found in the plot in the area were sampled. Analysis of the regeneration status of plant species in the botanical garden showed that 6.25% of tree/shrub species exhibited “Fair” regeneration status, 25% showed Poor regeneration status, and there are no tree/shrub species that had “Good” regeneration status in the circular plot of the sample in the Qes Diba botanical garden. A total of 25% of plant species were not regenerating at all, and 56.25% of plant species that were available only in a sapling or seedling stage were considered “New” in Qes Diba Botanical Garden. The species diversity assessed with the Shannon-Weiner (H') index in the study site was found to be 1.58. Employing systematic random sampling along transects, vegetation data from circular plots revealed a reverse J-shaped structural pattern and a low Shannon-Weiner diversity index (H'=1.58), indicating limited biodiversity. Alarmingly, regeneration assessment showed that only 6.25% of tree and shrub species exhibited fair regeneration, while 25% showed poor regeneration, and another 25% were not regenerating at all. The site's species composition was limited to 16 species, with a dominance of the Leguminosae family. These findings underscore a critical need for targeted conservation and management interventions to address the poor regeneration and low diversity observed.

The study was conducted in the Harego dry Afromontane forest, Northeastern Ethiopia, to analyze woody species composition, diversity, structure, and regeneration status. To collect the vegetation data, a total of 67 sample plots measuring 400 m 2 20 m × 20 m were laid systematically. Species identity, abundance, height, and diameter at breast height (DBH) were recorded for each sample plot. Diversity, structural, and regeneration status were analyzed for the forest. A total of 50 woody species representing 35 families and 44 genera were identified and recorded. According to the IUCN Red List Category, Rhus glutinosa A. Rich and Prunus africana (Hook.f.) Kalkm. are vulnerable species. Fabaceae was the dominant family, and of the total species, 27 were shrubs, 19 were trees, and 4 were climbers. The species accumulation curve indicates that the majority of plant species in the study area were captured by our sampling efforts. The values of true Shannon (N1 = 17) and true Simpson (N2 = 11) indicate that species in the Harego forest are more or less evenly distributed. The abundance-frequency ratio of all woody species (WI = &gt;0.05) indicates the heterogeneity of species composition. The total density and basal area were 4400 stems ha−1 and 9.66 m2 ha−1, respectively. The majority of the species fallen into the lower IVI classes. The diameter and height class distribution revealed an inverted J-shape. The increase in population demand and disturbance shows a high variation in stand structure and hampered natural regeneration, which needs immediate conservation actions.

Understanding population structure and regeneration status reflects the biological and ecological characteristics of the forest. The present study aims to know the population structure and regeneration status of Pinus-Quercus mixed forest in Bhardeu village of Lalitpur district, central Nepal. The study was carried out by laying down twenty-eight concentric circular plots of 8.92-meter radius randomly during 2021-2022. Altogether 28 tree species belonging to 24 genera and 17 families are recorded. Five species (Miliusa velutina, Cinnamomum camphora, Eriobotrya dubia, Maesa chisia and Saurauia napaulensis) were only recorded in adult form. The forest was found to be dominated by the species of Pinus and Quercus with the important value index (IVI) values ranging from 49.91 to 35.24. The average Simpson’s Diversity Index (1/D) is 2.88, Shannon Weiner’s Index is 0.85, species evenness is 0.57 and species richness is 1.07. The overall regeneration of the different species was seedlings 6484 individuals/ha., saplings 533 individuals/ha. and adults 1198 individuals/ha. showing fair regeneration. The majority of tree species show fair regeneration status (32.14%) followed by none regeneration (25%), new regeneration (17.85%), poor regeneration (14.28%) and good regeneration status (10.71%). The density diameter curve of the forest shows slightly flat reverse j-shaped structure indicating that majority of tree species were not in good regenerating status. The present analysis thus revealed that the population structure may get altered in future. Those species with none to poor regeneration status should be prioritized for the conservation and the proper management strategies need to be developed for sustainability of tree species in the forest.

Floristic composition, population structure, and regeneration status of woody species of Dabal forest found in East Hararghe zone of Oromia Regional State, Ethiopia, were studied. Vegetation data were obtained from 52 main plots of 20 × 20 m for mature woody species and 5 subplots of 5 × 5 m for seedlings and saplings. Density and dbh of each live woody plant species found in each sample plot were recorded. Frequency, basal area, importance value, and Shannon-Wiener diversity indices were also computed. Totally 59 woody plant species distributed in 33 families were documented. Of these, 45.80, 44.10, and 5.08% were shrubs, trees, and lianas, respectively. Species diversity and evenness indices were 3.56 and 0.87, respectively. Stem count of all woody species was 3379 stems ha-1. Out of this, 44.6, 30.8, and 24.59% were seedlings (dbh <3.5 cm), saplings (dbh between 3.5 and 10 cm), and mature (dbh >10 cm) individuals, respectively. Total basal area of all individuals with dbh ≥3.5 cm was 29.88 m2 ha-1. Juniperus procera, Cupressus lusitanica, Eucalyptus globulus, Afrocarpus falcatus, Eucalyptus camaldulensis, Myrsine africana, Maytenus undata, Hagenia abyssinica, Ekebergia capensis, and Cordia africana were species with top ten IVI. Most of these species were top densest, dominant, and frequent. Analysis of population structure based on pooled densities of all species in each dbh class showed that density of seedling > sapling > mature individuals, signifying healthy population structure with good natural regeneration potential. On individual basis, however, 35.6 and 8.5% of species showed fair and poor regeneration statuses, respectively, that deserve attention for conservation.