scholarly journals Population Structure and Regeneration Status of Woody Plants in Relation to the Human Interventions, Arasbaran Biosphere Reserve, Iran

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 191
Author(s):  
Sajad Ghanbari ◽  
Kiomars Sefidi ◽  
Christel C. Kern ◽  
Pedro Álvarez-Álvarez

Proper understanding of the diversity and natural structure of woody species and the impacts of human interventions are prerequisites for maintaining the remaining forests as well as restoration of deforested and degraded areas. This research was conducted to document the impact of human interventions on the population structure and the species diversity in the Arasbaran biosphere reserve in Iran due to the limited research and insufficient knowledge. The study area was divided into three adjacent sampling areas of low, medium, and high destruction intensity. Thirty fixed area 0.1-hectare plots were sampled to evaluate the composition, diversity, and species richness. Oak (Quercus macranthera), hawthorn (Crataegus meyeri), and maple (Acer campestre) were the top three dominant tree species at all the sites. The relative dominance of the top three species comprised 87.8% of the basal area of all species. The relative abundance of the top three species accounted for 68.1% of the species. The mean density and basal areas per tree across all three destruction statuses were 145 ± 59 stems ha−1 and 0.01 ± 0.005 m2 ha−1, respectively. The mean height of trees was different at low and high disturbance sites (4.6 ± 0.96 m and 3.37 ± 1.74 m, respectively). Due to the impact of human interventions on forest structure, composition, and diversity, conservation programs are recommended for implementation and in collaboration with local communities to employ management aimed at providing services for local people while restoring these forests. Basic ecological studies such as this study are the foundation to begin developing policies and management that meet multiple ecological and social goals.

Author(s):  
Samson Shimelse Jemaneh

This study was conducted with the objectives of study investigates, compare, and try to describe the floristic composition and structure of the vegetation of exclosures and open grazing lands. A stratified preferential sampling design technique with flexible systematic model was used for data collection. Data on vegetation and environmental parameters were gathered from 120 quadrants (90 from restorations or exclosures of different ages and 30 from adjacent open grazing lands), of 20 m x 20 m (400 m2) size. Species richness and the presence or absence of herbaceous plants were recorded like soil samples in a 2 m x 2 m (4 m2) subplot inside each main quadrant from five points, one at each corner and one at the center.  A total of 142 plant species belonging to 118 genera and 52 families were identified. All exclosures displayed higher plant species richness, diversity, and aboveground standing biomass compared to the adjacent open grazing lands. Consideration of edaphic (e.g. soil total nitrogen, available phosphorus, CEC, exchangeable bases, soil pH and soil texture) and site (e.g. Stoniness, Grazing) variables will help to optimize the selection of areas for the establishment of future exclosures. Moreover, our study suggests that with time exclosures may increasingly obtain an important role as refugees and species pool similar to church forests and should be protected and managed in a sustainable manner. However, economic and social impacts of exclosures should be included in feasibility studies before establishing exclosures in the future.  Altitude, Grazing and some soil parameters like Mg were the major environmental factors in the division of the vegetation into plant community types. The result of the frequency distribution of woody species showed a high proportion of small-sized individuals in the lower diameter classes indicating good recruitment potential of the forest patches and the rare occurrence of large individuals. Such trend was probably caused by past disturbance of the original vegetation resulting in a succession of secondary vegetation. In addition, the analysis of species population structure indicated that some tree species had abnormal population structure with no or few individuals at lower size classes. Moreover, assessment of regeneration status on the basis of age classes indicated that significant proportion of woody species were represented by few or no seedlings, entailing that they were under threat. Substantial numbers of forest species were found to have irregular population structure and are in reduced regeneration status. To prevent local extinction of these species, present efforts of nursery establishment and plantation of indigenous species in the exclosures should be strengthened and extended.


2021 ◽  
Author(s):  
Haileab Zegeye

Abstract Background: The remaining natural forests of Ethiopia are only small patches mostly confined to inaccessible areas and sacred places. Fach forest is one of the remnant dry evergreen Afromontane forests (DAFs) in northwestern Ethiopia. There is lack of information on the vegetation ecology of the forest. Thus, the present study was conducted to investigate the floristic composition and diversity, population structure, regeneration status and socio-economic importance of Fach forest, and the anthropogenic factors affecting it.Methods: Vegetation data were collected from a total of 34 plots, measuring 20 m × 20 m (400 m2) each and established along line transects approximately at 100 m intervals. A general survey consisting of field observations, key-informant interviews and Focus Group Discussion (FGD) was used to collect socio-economic data. Results: A total of 230 vascular plant species belonging to 183 genera and 76 families were recorded from the study area, of which 45 (19.57%) were trees, 62 (26.97%) trees/shrubs, 37 (16.09%) shrubs, 13 (5.65%) woody climbers, 10 (4.35%) herbaceous climbers, and 63 (27.39%) herbs. The family with the highest number of species was Fabaceae (28 species, 12.17% of all species), followed by Asteraceae (18 species, 7.83%), Poaceae (13 species, 5.65%), and Acanthaceae and Euphorbiaceae (9 species each). The Shannon-Wiener diversity and evenness values of woody species were 3.53 and 0.72, and the total density and basal area 4938.24 individuals ha-1 and 19.17 m2 ha-1, respectively. The species with the highest Importance Value Index (IVI) value was Combretum molle (25.26%), followed by Olea europaea subsp. cuspidata (21.19%), Dodonaea angustifolia (17.80%), and Calpurnia aurea (15.05%). The local communities were highly dependent on the forest for fuelwood, construction material, charcoal, timber and farm implements, as well as food (edible fruits), medicines, fodder, and bee forage. Fach forest is a protected area and contains sacred places, but at present it is dwindling mainly due to livestock grazing/browsing, tree cutting for various purposes, farmland expansion, rural settlements expansion, urbanization, fire incidences, and exotic species plantations at the expense of the natural forest, as well as soil erosion and climate change.Conclusions: Fach forest possesses high plant diversity and endemism. Woody species having low IVI values and poor regeneration status (as indicated by the Diameter at Breast Height [DBH] class distributions) need high priority for conservation. Fach forest has been maintained to the present-day through the combined indigenous (sacred grove) and modern (protected area system) conservation methods, but is now under increasing human pressure. Therefore, effective conservation and management interventions are urgently needed to ensure the long-term maintenance of the forest ecosystem, and benefit the local communities through sustainable utilization of the forest.


FLORESTA ◽  
2010 ◽  
Vol 40 (4) ◽  
Author(s):  
João Paulo Druszcz ◽  
Nelson Yoshihiro Nakajima ◽  
Sylvio Péllico Netto ◽  
Mauro Yoshitani Júnior

Este estudo objetivou comparar o método de amostragem de Bitterlich e o de área fixa com Parcela Circular. Estes dois métodos foram avaliados quanto à precisão e eficiência na estimativa das variáveis DAP médio, número de árvores, área basal e volume total, por hectare. Foram selecionadas três condições de plantios de Pinus taeda, localizados na fazenda Boa Vista, no município de Carambeí – PR. Na análise simultânea das três condições para as estimativas das variáveis DAP médio e número de árvores, por hectare, o método de amostragem de área fixa com Parcela Circular foi o mais preciso e eficiente. Já para a análise de área basal e volume total, por hectare, o método de amostragem de Bitterlich foi o mais preciso e eficiente. Conclui-se que o método de área fixa com Parcela Circular foi mais preciso e eficiente para a estimativa das variáveis DAP médio e número de árvores, já que se trata de um método no qual a seleção dos indivíduos é proporcional à área da parcela. O método de Bitterlich, por ser um método que faz a seleção dos indivíduos com probabilidade à área basal, foi mais preciso e eficiente para a estimativa das variáveis área basal e volume total.Palavras-chave: Método de amostragem; precisão e eficiência; Pinus taeda. AbstractComparison between Bitterlich and fixed area circular plot sampling methods in Pinus taeda L plantation. This study aimed to compare the Bitterlich sampling method to the fixed area circular plot. These two methods were evaluated with respect to the accuracy and efficiency for estimating the variables mean DBH, number of trees, basal area and total volume per hectare. Three conditions for Pinus taeda plantations were selected. They were located in Boa Vista farm, Carambeí County, State of Paraná. Results showed that the fixed area circular plot was more efficient and accurate to estimate the mean DBH and the number of trees per hectare because it is a method where the trees selection is proportional to the plot area, whereas the Bitterlich method was more efficient and accurate to estimate the basal area and the total volume per hectare because the trees selection is related to the basal area.Keywords: Sampling methods; accuracy and efficiency; Pinus taeda.


FLORESTA ◽  
2015 ◽  
Vol 45 (3) ◽  
pp. 523
Author(s):  
João Paulo Druszcz ◽  
Sebastião Do Amaral Machado ◽  
Nelson Yoshihiro Nakajima ◽  
Nelson Carlos Rosot ◽  
Roberto Tuyoshi Hosokawa

AbstractThis study aimed to compare two methods of sampling, one is the method of variable area represented by the Bitterlich point (PB) sampling and the other is the method of fixed area represented by circular plots (PC) with structural variation, the cross sampling cluster (CC) and the line sampling cluster (CL). Precision and efficiency in estimation of the variables mean DBH (cm), number of trees (N/ha), basal area (m2/ha) and total volume (m3/3) in three plantation conditions of Pinus taeda L., located in the city of Carambeí, Paraná, were assessed. In simultaneous analysis of the three conditions to estimate the mean DBH and number of trees per hectare variables, the sampling method of fixed area with Circular Plot (PC) was the most accurate and efficient. The Bitterlich point sampling method (PB) was more accurate and efficient for the estimation of basal area and total volume variables. The two structures of sampling method of the fixed area with Cross Cluster (CC) and with Line Cluster (CL) demonstrated good results being the line cluster superior to the cross cluster.ResumoEficiência do método de amostragem de Bitterlich e de área fixa com variações estruturais em plantações de Pinus taeda. O estudo visou comparar dois métodos de amostragem, sendo eles o de área variável, o qual foi representado pelo método Ponto de Bitterlich (PB) e o de área fixa, representado pela Parcela Circular (PC) e as variações estruturais em Conglomerado em Cruz (CC) e Conglomerado em Linha (CL) com subunidades circulares. Foram avaliadas a precisão e eficiência para a estimativa da variável DAP médio (cm), número de árvores (N/ha), área basal (m2/ha) e volume total (m3/ha), em três condições de plantações, localizadas no município de Carambeí, PR. Na análise simultânea das três condições para a estimativa da variável DAP médio (cm) e número de árvores (N/ha), o método de área fixa com Parcela Circular (PC) foi o mais preciso e eficiente. Para a estimativa da variável área basal (m2/ha) e volume total (m3/ha), o método de área variável Ponto de Bitterlich foi mais preciso e eficiente. As duas estruturas do método de área fixa, utilizando-se o Conglomerado em Cruz (CC) e o Conglomerado em Linha (CL) apresentaram resultados precisos e eficientes, entretanto, o CL foi superior ao CC.Palavras-chave: Eficiência relativa; precisão; reflorestamento.


Author(s):  
Nuru Mohammed

Aim: This study was conducted to assessing woody plant composition, population structure and regeneration status in lowland exclosure (EX) of Northern Ethiopia. Study Design: Investigation of parameters was undertaken from 71 plots with size of 20 m x 10 m laid systematically along transect lines for vegetation data. These 200 m2 plots were used for assessment of trees with DBH >5 cm. Small quadrats of 4 m*4 m (16 m2) nested within the bigger plots was laid at the four corners and center of each plots. These were used for measuring seedling and sapling individuals. To analyze species diversity, population structure and regeneration status of woody plants were by computing abundance, density, basal area, Importance value index (IVI) and using Shannon-Weiner diversity and evenness indices. Results: According to vegetation survey result, a total of 23, 17 and 26 woody species were recorded, at Kara, Erba and Shektekli exclosures (EXs), respectively. While 8, 7 and 5 species of woody plant were in open grazing land (OGL). The total mean densities of all woody plants were found to be 1530, 1480 and 2999 individual’s ha-1 at Kara, Erba and Shektekli in EXs. Conclusion: The study suggested that the regional government have to considering EXs as useful for restoration or rehabitation strategy in the region, the vegetation in all the EXs in the study sites have a higher species composition, diversity, density, increment of basal area and regeneration woody plants than OGL, as a result of management differences in EXs. However, there are also variation on species composition, diversity, density increment of basal area and regeneration woody plants among exclosures having similar age and altitude for instance the species recorded in Erba site is lower than with other of EXs, This could be due to among local site characteristic variation and high grazing happen before Ex establishment exists. Therefore, we need to apply soil and water conservation, enrichment planting with indigenous tree species and strengthen local management institution in effectively protect the exclosure.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Markos Kuma ◽  
Simon Shibru

Our current study was conducted in Oda forest to explore floristic composition, vegetation structure, and regeneration of woody species in a newly established Humbo Carbon Project. In the project, the above information for sufficient conservation and management of the forest is not well documented. Data were collected in October and December 2014. Thirty-two quadrats (20 m × 20 m) lying 100 m far apart were used for shrub and tree data. In each major plot, subplots (1 m2) were established at the center and corner for seedlings and saplings data. Altitude, slope, and aspect were measured using GPS and clinometers. DBH, basal area, and IVI were used for vegetation structure. Among 62 species confined in 32 families and 54 genera, Dodonaea angustifolia and Combretum molle were the densest and the most dominant and frequent species with higher IVI. Altitude and slope had significant effect (p<0.0001) on basal area and dominance. Bell and inverted J shaped patterns of selected woody species were identified. The seedling, sapling, and matured tree had 2.3%, 23.7%, and 74% density ha−1 of individuals, respectively. Generally, the study confirmed that very few species had dominance and abundance, influence of altitude and slope on species distribution, and fair regeneration of the forest.


2021 ◽  
pp. 1-9
Author(s):  
Keotshephile Kashe ◽  
Demel Teketay ◽  
Alison Heath ◽  
Mmusi Mmusi ◽  
Tumisang Mathope ◽  
...  

2014 ◽  
Vol 25 (2) ◽  
pp. 319-328 ◽  
Author(s):  
Muhamed Adem ◽  
Adefires Worku ◽  
Mulugeta Lemenih ◽  
Wubalem Tadesse ◽  
Jürgen Pretzsch

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1631
Author(s):  
Sajad Ghanbari ◽  
Christel C. Kern

The impact of fuelwood harvesting on forest structure and composition is not clear, especially on the understudied and scarce Arasbaran forests in Iran. This research compared woody species density, species diversity, forest composition, and regeneration status in areas of continuous and ceased fuelwood harvesting in Arasbaran forests. We expected fuelwood harvesting to decrease stem density, species diversity, tree size (diameter at the breast height (DBH) and height), and shift composition away from preferred fuelwood species. We measured woody species size and frequency and identified species in three fuelwood harvest and three no harvest sites, with six sample plots (100 m × 50 m) per site. Results tended to show differences in composition, diversity, woody species height, and density. Carpinus orientalis, a preferred fuelwood species, tended to be more dominant in no harvest (importance values index (IVI) = 173.4) than harvest areas (IVI = 4.4). The diversity or richness of woody species tended to be higher in harvest (20 ± 1 species per ha) than in no harvest (14 ± 2 species per ha) areas, and other measures of diversity supported this trend as well. Harvest areas tended to also be characterized by shorter tree height and lower density of trees, a higher density of regeneration, and fewer small pole-sized trees than no harvest areas. Ongoing fuelwood harvests may further shift composition and structure away from no harvest area, compromising future fuelwood availability, but further detailed research is needed. Close to nature practices may be useful in sustaining fuelwood harvest areas and diversifying areas where fuelwood harvesting has ceased.


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