Urban trees are valuable resources for urban areas as they have the capacity to reduce ambient temperatures, mitigate urban heat island effects and reduce runoff of rainwater playing an important role in mitigating the impacts of climate change by reducing atmospheric carbon dioxide (CO2). It also helps to reduce aerial suspended particulate matter, add visual appeal to the urban landscape sequestrating a significant amount of carbon from ambient atmospheric CO2. Carbon storage by urban trees in the ring road area of the Kathmandu Valley was quantified to assess the magnitude and role of urban forests in relation to mitigate the impact of global climate change. A total of 40 sample plots were placed randomly for the detailed carbon assessment. Aboveground and belowground carbon pools were considered in the detailed assessment. Furthermore, quality assurance (QA) and quality control (QC) were maintained through regular monitoring and capacity building of the field crews while collecting the bio-physical data. The assessment recorded a total of 33 different species of plants in the avenue’s plantation sites in ring road. The mean seedling, sapling, and tree density was found to be 2149585 and 185 per hectare. The mean carbon stock per hectare in the avenue plantation of the ring road area was 24.03 tC ha1 and the existing total carbon stock was 7785.72 tC in 2021. Likewise, the total baseline carbon dioxide equivalent (tCO2e) in the avenue plantation was found to be 28573.60 tCO2e. The carbon dioxide emission from the transport sector in the ring road area in a full movement scenario was 312888.00 tCO2e per annum, while the net emissions was 42547 tCO2e. There was a deficit of carbon dioxide in terms of stock by avenue plantations of 14000.8 tCO2e.This study indicates that the existing urban forest plantation is unable to sequestrate or offset the carbon dioxide that is emitted through the transportation sector. Consequently, open spaces like riverbanks and any other public lands, in which urban forests could be developed has to be planned for the green infrastructure and plantation of the multipurpose trees. The distinct values of forests in and around urban areas have to be recognized in the specific policies and plans for the sustainable management of urban and peri-urban forests to meet the adverse impact of global climate change. In addition, this study provides insights for decision-makers to better understand the role of urban forests and make sustainable management plans for urban forests in the cities like in Kathmandu Valley.

Low efficiency of earth kilns used in the carbonising process of wood to make charcoal has been reported as one of the sources of increasing charcoal wastes in the global south. However, the potential link and approaches of converting charcoal wastes-to-valuable energy and for the environmental health is not well known in Africa. Promoting local community capacity engagement in the production and reutilisation of recycled charcoal wastes at the households’ level is one of important measures to maintain environmental services for sustainability since households make decisions on the type of energy used. This paper, presents an approach of converting charcoal wastes to fuel energy for rural households and environmental health in Kilosa District, Tanzania. To achieve the objective of this research, the primary data were collected through interviews held with 298 randomly selected households, Focus Group Discussions and observations. IBM SPSS statistics version 20 Cross tab tools were used in the data analysis. Results revealed that the conversion of charcoal wastes-to-fuel energy approach used in this research demonstrates the ability of recyclable briquettes made from the locally available charcoal pollutants collected at different stages from earth kilns, to selling centers, improves tree harvest behaviour, adds another fuel energy source through reutilisation, and ultimate reduces pollution at the local level. Thus, the study provides a basis for policymakers to adopt charcoal wastes recycling strategies to address matters related to energy and ultimately enhances environmental health for sustainable development in Tanzania and beyond.

科学识别生态空间、合理预测主导生态系统服务功能时空变化趋势，是构建国土空间生态保护格局的基础，具有重要的理论意义和应用价值。目前，生态空间识别、功能分区和格局重构大多数以当前生态系统服务功能及其结构信息为参照，忽略了生态系统服务综合功能和主导生态系统服务功能的时空动态性，对未来生态空间主导生态系统服务功能变化模拟不重视，一定程度上影响了生态空间保护格局构建的合理性。本研究提出了一种基于生态系统服务功能动态变化特征的生态空间划定方法，实现了邛崃市生态空间范围识别，解决了当前研究忽略生态系统服务功能时空动态性的问题。在此基础上，研究还应用Markov-CA模型，集成主导生态系统服务功能时空变化特征，实现了2025年邛崃市生态空间主导生态系统服务功能时空变化模拟，为生态空间变化模拟寻找到了合适的方法，也为合理构建生态空间保护格局提供了基础支撑。研究发现邛崃市生态系统服务综合功能量及其年际变化率呈现出明显的动态性，这一发现证实我们在识别生态空间时考虑生态系统服务功能动态特性的必要性。应用本文提出的生态空间识别方法确定邛崃市生态空间面积为98307 ha，与地方生态文明建设规划中确定的相应生态空间范围基本一致，证实了立足于生态系统服务功能动态特性的生态空间划定方法的可靠性。研究结果还表明：2003—2019年，邛崃市主导生态系统服务功能表现出较强的非平稳性，这说明我们应当在生态空间保护格局构建中充分考虑主导生态系统服务功能动态性对未来生态空间功能格局的影响。Markov-CA模型高精度实现了邛崃市主导生态系统服务功能时空变化模拟，Kappa系数达到0.95以上，说明应用该模型模拟未来主导生态系统服务功能空间格局是可行的。模拟结果显示，2019—2025年，受生态系统服务功能非平稳性影响，邛崃市主导生态系统服务功能仍将发生相互转换，预计到2025年，生态空间仍然会保持初级产品生产、气候调节、水文调节三大主导生态系统服务功能，但面积将会发生变化，分别为32793 ha、52490 ha、13024 ha。研究可以为生态保护红线划定、生态功能分区和生态空间保护格局构建提供科学参考。

Abstract: By studying the structural characteristics and carbon storage of the mangrove island ecosystem in the 
Beibu Gulf, this study provides a scientific basis for mangrove ecological compensation in the coastal areas of 
Guangxi, South China Sea. On the basis of the unmanned aerial vehicle remote sensing images and a sample plot 
survey, the object-oriented multi-scale segmentation algorithm is used to extract the mangrove community type information, and one-way analysis of variance is conducted to analyse the structural characteristics of the mangrove 
community. The carbon storage and carbon density of different mangrove ecosystems were obtained based on the 
allometric growth equation of mangrove plants. The analysis yielded four main results. (1) The island group covers 
about 27.10 ha, 41.32% (11.20 ha) of which represents mangrove areas. The mangrove forest is widely distributed 
in the tidal flats around the islands. (2) The main mangrove types were Aegiceras corniculatum, Kandelia obovata + 
Aegiceras corniculatum, Avicennia marina + Aegiceras corniculatum and Avicennia marina communities. (3) 
Amongst the mangrove plants, Avicennia marina had the highest biomass (18.52 kg plant–1), followed by Kandelia 
obovata (7.84 kg plant–1) and Aegiceras corniculatum (3.85 kg plant–1). (4) The mangrove carbon density difference 
was significant. Kandelia obovata had the highest carbon density (148.03 t ha–1), followed by Avicennia marina
(104.79 t ha–1) and Aegiceras corniculatum (99.24 t ha–1). The carbon storage of the mangrove island ecosystem 
was 1194.70 t, which was higher than in other areas with the same latitude. The carbon sequestration capacity of 
the mangrove was relatively strong.