## 1 Introduction  
The global population in urban areas grew tenfold in the last century and over half of the people live in towns or cities today, with a projected number of more than 60% by 2030 [1, 2]. Cities provide more advanced infrastructure such as recreation spots, convenient transportation, and better health care systems than in the countryside. The advantages of living in cities combined with the population growth attract more people crowding into cities, causing loss or degradation of green vegetation space [3, 4], which in turn degrades vegetation carbon sequestration. Vegetation in urban landscapes plays multiple roles, including mitigation of heat islands, purification of air quality, and reduction of urban noises [5, 6]. Urban vegetation also contributes to atmospheric carbon dioxide (CO\({}_{2}\)) removal. Cities are responsible for more than 70% of the greenhouse gas (GHG) emissions with CO\({}_{2}\) as the primary component [7]. A growing number of cities have recognized their potential contribution to mitigate climate change and asypied to achieve net-zero [8]. Clean energy and energy efficiency are probably the mainstream topics to achieve carbon-neutral cities [9]. Cities cannot achieve net-zero by reducing emissions without improving vegetation carbon sequestration from urban and regional landscapes [8]. Land-based GHGremoval options can contribute positively to urban ecosystem services [10]. One of the important issues for sustainable urban development is to protect vegetation cover and increase carbon sequestration [11]. An urban ecosystem involves social, ecological, and physical components which interact to create a unique environment and urban infrastructure [12]. Land-based carbon sequestration is the process of capturing and storing organic carbon in biological forms, driven by vegetation assimilation of CO\({}_{2}\) from the atmosphere through photosynthesis [13]. Vegetation is the pivotal element for the carbon sequestration process. Several indices have been proposed to measure and evaluate carbon sequestration from vegetation, including gross primary productivity (GPP), net primary productivity (NPP), and net ecosystem productivity (NEP) which are, though from different aspects, closely correlated [14; 15]. The indices are important for assessing and comparing vegetation carbon sequestration from urban ecosystems at regional or larger scales. Urban areas characterize different land (vegetation) cover types, including build-up of settlements as well as croplands, pastures, and/or forests [16; 17]. Vegetation is a core component of nearly all the urban land cover types [18]. Urban land management intends to maximize land benefits with consideration of landscape of vegetation cover. Land management can have location-specific impact on urban vegetation [10]. Several methods have been proposed to improve urban vegetation cover, including reducing roadside constraints, tackling underground utility restrictions to allow tree root growth, and even tree trunk injection for better protection from pests and diseases [19]. Further, from landscape and urban ecology principles, designing shape and connectivity of green spaces and creating green wedges are also among the land management practices for vegetation recovery and enhancement [20; 21]. Optimal land management for a sustainable urban development is a harmony between the nature and the interventions that take full advantage of nature to provide solutions to specific targets, e.g., climate mitigation and adaptation challenges, which is also the core notion from nature-based solutions (NBSs) [22]. Though traditional land use and land cover changes, e.g., converting croplands to forests (afforestation), are capable of increasing vegetation cover, large scale afforestation is rarely practical due to food security [23]. Remote sensing technology allows the mapping of key environment variables, vegetation cover, and carbon sequestration from vegetation in an efficient and effective manner [24; 25].