scholarly journals Altitudinal variation in plant community, population structure and carbon stock of Quercus semecarpifolia Sm. forest in Kumaun Himalaya

2022 ◽  
Vol 43 (1) ◽  
pp. 133-146
Author(s):  
A. Fartyal ◽  
◽  
K. Khatri ◽  
K. Bargali ◽  
S.S. Bargali ◽  
...  

Aim: To study the impact of altitudinal variation on plant community composition, structure, dispersion and regeneration status of Quercus semecarpifolia forest in Kumaun Himalaya. Methodology: Along the altitudinal gradient, the forest stands between 2400 and 2610 m asl were selected at low, mid and high altitude. The phyto-sociological analysis was carried by laying ten quadrats of 10m × 10m at each site. Soil samples were collected with the help of soil corer from two depths. Various ecological indices and population structure were investigated for each forest stand and regeneration status of forest was predicted by the population size of seedlings, saplings and trees. Tree biomass was estimated using allomatric equations and carbon stock was determined by multiplying biomass of species to factor 0.475. Results: With increasing altitude the number of tree species decreased and the shrub species richness increased, while herb species showed a unimodel pattern. Q. semecarpifolia was the dominant tree species at all the three sites with the IVI values of 220.14, 255.22 and 286.23 at LA, MA and HA, respectively. A complete absence of Q. semecarpifolia seedlings indicated no regeneration in low and high altitude stands while low proportion of seedlings in mid altitude forest stand indicated poor regeneration. Soil was acidic (pH 5.66-5.86), with higher silt content and showed decreasing pattern in physico-chemical properties with increasing altitude. The biomass of tree layer ranged from 871.49 to 1050.17 t ha-1. The tree layer carbon stock was maximum in high altitude forest (498.84 t ha-1) which was largely contributed by bole, stump roots and branches. Interpretation: Variation in species richness, distribution pattern and regeneration potential is related to site characteristics governed by altitude and require various efforts to conserve and protect these forests to check ecosystem imbalance.

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.


2020 ◽  
Vol 44 (1) ◽  
Author(s):  
Man Kumar Dhamala ◽  
Prakash Chandra Aryal ◽  
Madan Krishna Suwal ◽  
Sijar Bhatta ◽  
Dinesh Raj Bhuju

Abstract Background The Himalayan forests are of great importance to sustain the nature and community resource demands. These forests are facing pressures both from anthropogenic activities and ongoing global climatic changes. Poor natural regeneration has been considered a major problem in mountainous forests. To understand the population structure and regeneration status of Larix (Larix griffithiana and Larix himalaica), we conducted systematic vegetation surveys in three high-altitude valleys namely Ghunsa (Kanchenjunga Conservation Area, KCA), Langtang (Langtang National Park, LNP), and Tsum (Manaslu Conservation Area, MCA) in Nepal Himalaya. The average values of diameter at breast height (DBH), height, and sapling height were compared for three sites and two species using Kruskal-Wallis test. Population structure was assessed in terms of proportion of seedlings, saplings, and trees. Regeneration was analyzed using graphical representation of frequencies of seedlings, saplings, and trees in histograms. Results The results showed that the population structure of Larix in terms of the proportion of seedling, sapling, and tree varied greatly in the three study areas. KCA had the highest record of seedling, sapling, and tree compared to other two sites. Seedlings were the least among three forms and many plots were without seedlings. We found no seedling in MCA study plots. The plot level average DBH variation among sites was significant (Kruskal-Wallis χ2 = 7.813, df = 2, p = 0.02) as was between species (Kruskal-Wallis χ2 = 5.9829, df = 1, p = 0.014). Similarly, the variation in average tree height was significant (Kruskal-Wallis χ2 = 134.23, df = 2, p < 0.001) among sites as well as between species (Kruskal-Wallis χ2 = 128.01, df = 1, p < 0.001). All the sites showed reverse J-shaped curve but more pronounced for KCA and MCA. In comparing the two species, Larix griffithiana has clear reverse J-shaped diameter distribution but not Larix himalaica. Conclusion The varied responses of Larix manifested through regeneration status from spatially distinct areas show that regeneration limitations might be more pronounced in the future. In all the three studied valleys, regeneration of Larix is found to be problematic and specifically for Larix griffithiana in MCA and Larix himalaica in LNP. To address the issues of disturbances, especially serious in LNP, management interventions are recommended to sustain the unique Himalayan endemic conifer.


Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 552
Author(s):  
Janez Kermavnar ◽  
Lado Kutnar ◽  
Aleksander Marinšek

Forest herb-layer vegetation responds sensitively to environmental conditions. This paper compares drivers of both taxonomic, i.e., species richness, cover and evenness, and functional herb-layer diversity, i.e., the diversity of clonal, bud bank and leaf-height-seed plant traits. We investigated the dependence of herb-layer diversity on ecological determinants related to soil properties, climatic parameters, forest stand characteristics, and topographic and abiotic and biotic factors associated with forest floor structure. The study was conducted in different forest types in Slovenia, using vegetation and environmental data from 50 monitoring plots (400 m2 each) belonging to the ICP Forests Level I and II network. The main objective was to first identify significant ecological predictors and then quantify their relative importance. Species richness was strongly determined by forest stand characteristics, such as richness of the shrub layer, tree layer shade-casting ability as a proxy for light availability and tree species composition. It showed a clear positive relation to soil pH. Variation in herb-layer cover was also best explained by forest stand characteristics and, to a lesser extent, by structural factors such as moss cover. Species evenness was associated with tree species composition, shrub layer cover and soil pH. Various ecological determinants were decisive for the diversity of below-ground traits, i.e., clonal and bud bank traits. For these two trait groups we observed a substantial climatic signal that was completely absent for taxonomy-based measures of diversity. In contrast, above-ground leaf-height-seed (LHS) traits were driven exclusively by soil reaction and nitrogen availability. In synthesis, local stand characteristics and soil properties acted as the main controlling factors for both species and trait diversity in herb-layer communities across Slovenia, confirming many previous studies. Our findings suggest that the taxonomic and functional facets of herb-layer vegetation are mainly influenced by a similar set of ecological determinants. However, their relative importance varies among individual taxonomy- and functional trait-based diversity measures. Integrating multi-faceted approaches can provide complementary information on patterns of herb-layer diversity in European forest plant communities.


2017 ◽  
Vol 7 (23) ◽  
pp. 10233-10242 ◽  
Author(s):  
Jacob Nabe-Nielsen ◽  
Signe Normand ◽  
Francis K. C. Hui ◽  
Laerke Stewart ◽  
Christian Bay ◽  
...  

2021 ◽  
Vol 272 ◽  
pp. 01002
Author(s):  
Huan Dai ◽  
Wei Li ◽  
Yan Zeng ◽  
Xinyang Zhang

Studying on Qinglongshan Forest Park in Wuhan by typical plot method, 15 typical plots in the park were investigated, and the species richness index, diversity index, evenness index, frequency and important value index were calculated. The results showed that there were 139 species of woody plants belonging to 46 families and 97 genera, including 41 species of evergreen trees, 32 species of deciduous trees, 62 species of evergreen shrubs, 25 species of deciduous shrubs, and 4 species of bamboo belonging to 1 family, 3 genera. Species richness index and Simpson diversity index were all expressed as tree layer > shrub layer, evergreen species > deciduous species. Pielou evenness was tree layer > shrub layer. This study can provide some reference for understanding the existing plant status of forest parks, carrying out science popularization, scientific research, protection and improvement of forest landscape quality.


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