scholarly journals Forest Structure and Composition under Contrasting Precipitation Regimes in the High Mountains, Western Nepal

2021 ◽  
Vol 13 (13) ◽  
pp. 7510
Author(s):  
Kishor Prasad Bhatta ◽  
Anisha Aryal ◽  
Himlal Baral ◽  
Sujan Khanal ◽  
Amul Kumar Acharya ◽  
...  

The high mountains stretch over 20.4% of Nepal’s land surface with diverse climatic conditions and associated vegetation types. An understanding of tree species and forest structural pattern variations across different climatic regions is crucial for mountain ecology. This study strived to carry out a comparative evaluation of species diversity, main stand variables, and canopy cover of forests with contrasting precipitation conditions in the Annapurna range. Firstly, climate data provided by CHELSA version 1.2, were used to identify distinct precipitation regimes. Lamjung and Mustang were selected as two contrasting precipitation regions, and have average annual precipitation of 2965 mm and 723 mm, respectively. Stratified random sampling was used to study 16 plots, each measuring 500 m2 and near the tree line at an elevation range of 3000 to 4000 m across different precipitation conditions. In total, 870 trees were identified and measured. Five hemispherical photos using a fisheye lens were taken in each plot for recording and analyzing canopy cover. Margalef’s index was used to measure species richness, while two diversity indices: the Shannon–Wiener Index and Simpson Index were used for species diversity. Dominant tree species in both study regions were identified through the Important Value Index (IVI). The Wilcoxon rank-sum test was employed to determine the differences in forest structure and composition variables between the two precipitation regimes. In total, 13 species were recorded with broadleaved species predominating in the high precipitation region and coniferous species in the low precipitation region. Higher species richness and species diversity were recorded in the low precipitation region, whereas the main stand variables: basal area and stem density were found to be higher in the high precipitation region. Overall, an inverse J-shaped diameter distribution was found in both precipitation regions signifying uneven-aged forest. A higher proportion of leaning and buttressed trees were recorded in the high precipitation region. However, similar forest canopy cover conditions (>90%) were observed in both study regions. The findings of this research provide a comprehensive narrative of tree species and forest structure across distinct precipitation regimes, which can be crucial to administrators and local people for the sustainable management of resources in this complex region.

2005 ◽  
Vol 35 (1) ◽  
pp. 175-188 ◽  
Author(s):  
Toshiya Yoshida ◽  
Yoko Iga ◽  
Megumi Ozawa ◽  
Mahoko Noguchi ◽  
Hideaki Shibata

Scarification is widely conducted in northern Japan to remove understory dwarf bamboo species in degraded forests for replacement with tree species. To explore ways to enhance species diversity and restoration of mixed forest at the treated site, we clarified the mechanisms that lead to compositional heterogeneity of plant species. We evaluated the relative importance of environmental factors (scarification properties, soil properties, light conditions, litter cover, and presence of canopy trees) for the demography of tall tree species (emergence, mortality, and growth) and whole vegetation structure (species diversity and composition) over the two growing seasons immediately following scarification. Of tall tree species, Betula spp. were dominant (60% in total density), followed by Abies sachalinensis (Fr. Schm.) Masters, Acer mono Maxim., and Phellodendron amurense Rupr. Light intensity was an important factor, having mostly negative effects on the demography of these species. Soil factors (e.g., nitrogen content, moisture) affected the demography mainly of shade-intolerant or hygrophilous species. In general, extreme environmental conditions led to the dominance of grasses, forbs, and lianas rather than tall trees. Maintenance of canopy cover, which limits light and supplies seeds as well as litter, proved to be most important in promoting plant species diversification on the scarification site.


2016 ◽  
Vol 27 (6) ◽  
pp. 1151-1163 ◽  
Author(s):  
Christopher R. Hakkenberg ◽  
Conghe Song ◽  
Robert K. Peet ◽  
Peter S. White

Plant Ecology ◽  
2010 ◽  
Vol 210 (1) ◽  
pp. 67-84 ◽  
Author(s):  
Robin M. Reich ◽  
Charles D. Bonham ◽  
Celedonio Aguirre-Bravo ◽  
Migel Chazaro-Basañeza

Tropics ◽  
2003 ◽  
Vol 12 (2) ◽  
pp. 85-102 ◽  
Author(s):  
Sakhan TEEJUNTUK ◽  
Pongsak SAHUNALU ◽  
Katsutoshi SAKURAI ◽  
Witchaphart SUNGPALEE

Author(s):  
Alebachew Abebe Alemu ◽  
Habtamu Kiros ◽  
Eba Muluneh Sorecha

Clearing of natural ecosystems and land degradation due to unsustainable agricultural practices are becoming threats to the sustainability and productivity of agricultural systems in Burie town administrative, Amhara National Regional State, Ethiopia. The aim of this paper is therefore to assess the fruit tree species diversity in home garden agro-forestry and their role for supporting local people’s livelihoods in Burie town administration. Cultivated plants of 72 home gardens were surveyed and critical information were collected through questioner and focus group discussion from 12 households. Fruit tree species diversity (expressed in species richness and evenness) in home gardens in the study sites was determined using the Shannon-Weiner Index. The study basically considers the human consumption fruit trees species. A total of 18 fruit tree species represented by 9-genera and 7-families were recorded in home garden agro-forestry within the three wealth status (poor, medium, and rich) of the selected respondents commonly. From all wealth categories, the highest Shannon diversity index was recorded in rich and the lowest was in poor class category. Similarly, the highest species evenness was recorded in rich wealth category. However, there was no significant difference among rich and medium wealth categories for species richness. The study also revealed that age, land hold size, education status is the cause for species diversity in addition to the wealth status in the study area. Older respondents had significantly higher species richness and diversity than youngsters. It has been also found that almost all (100%) of the sampled households harvest and use at least four types of home garden products for various purposes. Lacks of management practices were the factors which puts the species diversity in question in the study area.


Author(s):  
Sabelo Madonsela ◽  
Moses Azong Cho ◽  
Abel Ramoelo ◽  
Onisimo Mutanga ◽  
Laven Naidoo

2004 ◽  
Vol 34 (3) ◽  
pp. 435-443 ◽  
Author(s):  
Rodolfo Salm

This study investigates patterns of forest structure and tree species diversity in an anthropogenic palm grove and undisturbed areas at the seasonally-dry Pinkaití research station, in the Kayapó Indigenous Area. This site, managed by the Conservation International do Brasil, is the most southeastern site floristically surveyed in the Amazon until now. The secondary and a nearby undisturbed forest were sampled in a group of 52 floristic plots of 0.0625-ha (25x25-m) where all trees with DBH > 10 cm were measured and identified. The analyses were complemented with other two floristic plots of 1-ha (10x1000-m). The present study has shown that the Pinkaití, like other seasonally-dry forests, have great heterogeneity in forest structure and composition, associated with biotic characteristics of the most important tree species, natural disturbance and history of land-use. The palm grove, moderately dominated by the arborescent palm Attalea maripa (Aubl.) Mart., presented high tree species diversity and was floristically similar to undisturbed forests at the study site. It is discussed the importance of large arborescent palms for the seasonally-dry Amazon forests regeneration.


2021 ◽  
Author(s):  
Van Vien Pham ◽  
Christian Ammer ◽  
Peter Annighöfer ◽  
Steffi Heinrichs

Abstract Background: Forest regeneration is decisive for future forest development and therefore of major concern to forest ecologists. The ability of overstory tree species to regenerate successfully is important for the preservation of tree species diversity and its associated flora and fauna. This study investigated forest regeneration dynamics in the Cat Ba National Park, a biodiversity hotpot in Vietnam. Data was collected from 90 sample plots and 450 sub-sample plots in the regional limestone forests. We compared species richness between the regeneration and overstory tree layers and examined the effect of environmental factors on the occurrence of regeneration. We developed five ratios to relate overstory and regeneration richness and diversity. Results: We found 97 tree species in the regeneration layer compared to 136 species in the overstory layer. Average regeneration density was 3,764 ± 1,601 per ha. Around 70% of the overstory tree species generated offspring. Of the tree species threatened according to The International Union for Conservation of Nature’s Red List of Threatened Species, only 36% were found in the regeneration layer. A principal component analysis provided evidence that the regeneration of tree species was linked to terrain factors (percentage of rock surface, slope) and soil properties (Cation exchange capacity, pH, humus content, soil moisture, soil depth). Contrary to our expectations, the prevailing light conditions (total site factor, gap fraction, openness, indirect site factor, direct site factor) had no influence on regeneration density and composition, probably due to the small gradient in light availability. Conclusion: We conclude that tree species richness in Cat Ba National Park appears to be declining at present. We suggest similar investigations in other biodiversity hotspots to learn whether the observed trend is a global phenomenon. In any case, a conservation strategy for the threatened tree species in the Cat Ba National Park needs to be developed if tree species diversity is to be maintained.


2014 ◽  
Vol 6 (4) ◽  
pp. 448-453 ◽  
Author(s):  
Dumpa PREMAVANI ◽  
Maradana TARAKESWARA NAIDU ◽  
Malleboyina VENKAIAH

The tree species diversity and population structure were studied in four stands of the tropical forests in the north-central Eastern Ghats, based on tree inventories conducted on four 1-ha plots. In the four independent plots, two 5 x 1000 m transects were established and all trees with ≥ 15 cm girth at breast height were enumerated. The density, frequency, basal area and IVI along with diversity indices viz. Shannon index, species richness, equitability and species dominance were computed to see the variation in tree community. A total of 92 species representing 73 genera under 40 families of angiosperms were recorded. Tree species richness was as low as 34 species per hectare plot in Geddapalli to as high as 48 species in Koruturu. Tree density ranged from 360 stems per hectare in plot Geddapalli to 526 stems in plot Chintapalli and that of total basal area from 16.31 m2 ha-1 in Koruturu to 31.15 m2 ha-1 in Chintapalli. The number of species and stems decreased from the smaller to the largest girth classes. The tree inventories of the study area when compared to those of the other tropical forests showed great differences in density and basal area. This may probably be due to differences in geography and annual rainfall patterns. The information on tree species structure and function can provide baseline information for conservation of the biodiversity.


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