Banko Janakari

Environmental conundrum: urgency of managing invasive alien species

Lila Nath Sharma — Sun, 31 Dec 2023 00:00:00 +0000

Developing stem taper of Shorea robusta in the far-western Terai of Nepal

Sun, 31 Dec 2023 00:00:00 +0000

Tree taper functions expressed in terms of height and diameter at breast height (BDH) can provide accurate and timely information on current growing stock. Taper equations are very important for calculation of growing stock in forest inventories, however, in the context of Nepal, these are still unavailable at the required level. The study aimed to develop taper equations, so that those can be used to predict the diameter anywhere along the stem, and estimate tree volumes at desired sections. The input data was a destructive sampling method of 81 sample trees of Shorea robusta distributed in ten locations of the far western Terai of Nepal (Kailali and Kanchanpur districts).

Using two independent B-Spline and 5th-degree polynomial taper models, the upper stem diameters were imputed. Both models were applied on the whole dataset, irrespective of DBH size, to get common fitted taper models. Later, the same models were tested for three different DBH classes to compare and evaluate the best-fit model.

Taper models, developed under the B-spline polynomial model of 3^rd degree, were found to be highly dependent on the tree (DBH) sizes. Thus, better models could be developed by classifying the whole dataset based on different DBH classes. On the other hand, developed models under the 5^th degree polynomial taper model did not exhibit their dependency on the tree (DBH) sizes and a better model was found for the unclassified datasets, i.e. for all DBH sizes.

Plant communities in Shivapuri Nagarjun National Park, Central Nepal

Sun, 31 Dec 2023 00:00:00 +0000

This study analyzes the plant communities in the Shivapuri Nagarjun National Park (SNPP), Nepal. A survey was done in the National Park in 2020 using quadrat sampling. The study sites were characterized by specific plant communities Four different sites, Sundarijal (SJ), Panimuhan (PA), Okhreni (OK), and Bagdwar (BD) were identified for the sampling based on elevation and aspects. The density, frequency, IVI, basal area, DBH, and diversity indices of plant species were measured. A total of 32 tree species representing 30 genera and 19 families were identified. Quercus semecarpifolia, Lindera nacusua, Castanopsis tribuloides, and Schima wallichii showed the highest density and IVI in BD, OK, SJ, and PA, sites, respectively. Q. semecarpifolia and, Pyrus pashia, S. wallichii and C. tribuloides were the most frequent species in BD, OK, SJ, and PA, sites, respectively. Similarly, the species Q. semecarpifolia, Pinus roxburghii, C. tribuloides and S. wallichii were the species having the highest basal area in the BD, OK, SJ, and PA sites, respectively. The BD site harbors numerous trees with DBH exceeding 50 cm, whereas the SJ site boasts a significant abundance of trees with DBH below 25 cm. The effect of the tree canopy, litter, and shrub cover, grazing, and cutting on species composition was found significant. Simpson's diversity index ranged from 0.72 - 0.88, and the Shannon-Weiner index from 1.79- 2.49. Similarly, Pielou’s evenness was 0.32 - 0.47.

Impact of silviculture system on regeneration status and species diversity: reflection from far-western lowland, Nepal

Prakash Ojha, Keshav Raj Acharya, Aliza Subedi, Siddhartha Regmi — Sun, 31 Dec 2023 00:00:00 +0000

Adoption of silvicultural system aims to enhance the regeneration of desired species. Irregular shelterwood system was initiated in Shorea robusta dominated forest under different forest management regimes including community forest in lowland forest of Nepal. The present study was conducted in 2023 to compare the regeneration status and species diversity between the two different management practices (scientific forest management and conventional forest management) in Patela Community Forest in far-western lowland of Nepal. A total of 27 quadrat sample plots (each with 4 m²) were established at a spacing of 50 m x 50 m across the three scientifically managed blocks, each with an area of 2.14 ha. An equal number of sample plots (27) were established within the conventionally managed blocks. Important Value Index, Sorenson’s Similarity Indices, and the distribution patterns of each species were calculated in both the management blocks to compare the species diversity. Shapiro-Wilk test was performed to check the normality of regeneration count, and a two-sample t-test was employed to examine the significant differences in the mean count of the plant species. The present study revealed that the conventionally managed forest block has higher species diversity; however, the number of seedlings was significantly high in the scientifically managed forest blocks. The Important Value Index Analysis indicated that S. robusta was dominant tree species in both the management blocks followed by Terminalia tomentosa; however, there was higher number of S. robusta regeneration under the scientifically managed blocks. The study concludes that irregular shelter-wood system is effective for regulating S. robusta forests in the western lowlands of Nepal.

Status, opportunities, and challenges of agroforestry practices: perspectives from Terhathum district, Nepal

Gyanendra Regmi, Utsab Thapa — Sun, 31 Dec 2023 00:00:00 +0000

Tree cultivation in agricultural and public spaces serves as an alternative to fulfill the rural population's demand for forest products. However, agroforestry practices in Nepal, categorized by agro-ecological areas, lack sufficient documentation and improvement. The current investigation, undertaken in the Myaglung Municipality of Terhathum district in Nepal, aimed to examine the current practices and preferences related to agroforestry. The study also sought to uncover potential opportunities and challenges inherent in agroforestry while gauging the local community's perceptions regarding agroforestry. The primary data collection employed household interviews, key informant interviews, focus group discussions, and direct field observations while the secondary data were gathered from various public and unpublished sources. The farmers' preferences were evaluated using a five-point Likert Scale. In the study region, seven agroforestry systems, mainly employed for subsistence, were identified. The popular timber species in agroforestry included Alnus nepalensis, Schima wallichii, Castanopsis hystrix, C. tribuloides, and Pinus roxburghii. The favored fodder species were Ficus roxburghii, F. nemoralis, Artocarpus lakoochaa, Litsea monopetala, and Morus alba. On the other hand, the top fruit choices were Citrus reticulata, C. limon, Musa paradisica, Mangifera indica, and Litchi chinensis. The key barrier for agroforestry growth was the lack of technical knowledge in cultivating, managing, and harvesting agroforestry species, requiring attention for future agroforestry development in the region.

Forest diversity and aboveground carbon linkage between the national park and community managed tropical forests of Nepal

Sunita Ranabhat, Rajesh Malla — Sun, 31 Dec 2023 00:00:00 +0000

The relationship of forest diversity and aboveground carbon has been poorly explored in tropical forests under different management regimes. An assessment of the linkage between forest diversity and carbon has become important, particularly to devise effective approaches to forest management and policy formulation. To assess the relation between forest diversity and carbon stock, we correlated the structural attributes (i.e., DBH, height, wood density, and stem density), diversity attributes (i.e., species richness, Shannon Weiner index and Shannon equitability index) and aboveground carbon of tree species ≥ 5cm in DBH from Bardia National Park and adjoining Buffer zone Community Forest. Our results showed that most structural attributes are correlated to aboveground carbon in both forest types. While the diversity attributes (i.e., species richness and Shannon index) and stem density had no relation with aboveground carbon in both forests. Similarly, species evenness had a significant inverse relation with aboveground carbon in both forests. The correlation of DBH and height was stronger with aboveground carbon in community managed forest while the same was moderate in national park. In addition, the carbon stock was found slightly higher in the community managed forest than in national park. This indicates that forest structural diversity enhances the aboveground carbon in tropical forests, and community managed forest promotes the better growth of vegetation. These results provide a better insight into forest management and its effects on forest diversity and aboveground carbon.

Wetland city accreditation in Nepal: an approach to wetland management for livable cities and urban resilience

Sun, 31 Dec 2023 00:00:00 +0000

The Ramsar Wetland City Accreditation encourages conservation and wise use of urban and peri-urban wetlands and promotes sustainable socio-economic benefits for local communities. It recognizes cities that value and protect their wetlands, fostering positive relationships with these ecosystems and increasing awareness in municipal planning and decision-making processes. A city's commitment to wetland conservation, awareness, active engagement in sustainable practices, and integration of wetland conservation into planning makes it a strong candidate for this recognition. Currently, 43 cities worldwide have achieved this accreditation since 2017; however, Nepalese cities, endowed with rich wetlands, are yet to be accredited. This study delves into the wetland-rich cities of Nepal, identifying five potential candidates for accreditation based on a comprehensive assessment. Following the assessment aligned with the Ramsar Convention requirements, Pokhara City (Kaski district) emerged as the top candidate for Ramsar Wetland City Accreditation in Nepal. The subsequent rankings include Sandakpur Rural Municipality (Ilam district), Bharatpur Metropolitan City (Chitwan district), Ghodaghodi Municipality (Kailali district), and Kapilvastu Rural Municipality (Kapilvastu district), respectively.