## 1 Introduction  
Forests are ecosystems maintaining bioresources and providing a range of products and services to meet human needs [1, 2]. As reported, 31% of the total Earth's land surface is covered by forests that play a significant role in maintaining ecosystems and providing food, fodder, and shelter. Forests are also instrumental in controlling land degradation by minimizing soil erosion and desertification. Furthermore, even biological diversity in a regional ecosystem is directly affected by surrounding forest cover [3]. Forest biomass is considered reservoirs of carbon. Forests directly have a crucial role in the carbon and water cycle, gross and net primary production (_GPP_ and _NPP_), climate changes and global warming, radiation and environment balance, even air quality, and human activities [1, 4]. Accurate forest above ground biomass (_AGB_) assessment is crucial for forest resources evaluation, carbon cycle assessment, and sustainable forest management [1, 2, 3, 4]. Therefore, forest _AGB_ evaluation is essential to recognize possible climate change due to deforestation and global ecological balance, as well as promoting global biological evolution, community succession, and mitigation processes [1; 5; 6]. Globally, the rapidly deteriorating forest might be a big threat not only for forest resources but also for future ecological balance [1]. Thus, accurate assessment and monitoring of forest \(AGB\) for sustainable management and mitigation, and also to recognize climate change scenario due to deforestation are important and crucial [1; 5; 6]. Forests have great potential to fuel the next generation by harvesting byproducts (e.g., brushwood, lumber, firewood) and supplying a large portion of renewable materials (e.g., edible fruits, nuts, paper, medicinal herbs) that can be converted into renewable energy [1; 2; 3; 4; 7; 8; 9]. The forest biomass evaluation is extremely important to assess renewable energy sources and future planning to keep balance in our environment, economy, and energy security [1; 2; 3; 4]. Therefore, forest biomass evaluation and monitoring are crucial to assess the bioresources and terrestrial ecosystem. Forests are considered to be a carbon sink. Forests absorb carbon from the atmosphere through photosynthesis and store it in plant tissue. At a regional as well as global level, estimating the biomass of forest vegetation is an important exercise in determining the storage of carbon in the dominant tree component and computing carbon cycling. It then becomes deposited in forest biomass (that is, trunks, branches, roots, and leaves), in dead organic matter (litter and deadwood), and in soils. This process of carbon absorption and deposition by the forest vegetation is known as carbon sequestration, which can help sustainable management of natural resources. For mitigating \(CO_{2}\) emissions through carbon sequestration, this driver of climate change has drawn considerable attention to forest ecosystems as a viable option [10]. Globally, the advanced and rapid global observation systems and analyses of geospatial natural resources using remote sensing techniques are being developed. Remote sensing is state-of-the-art, fast, cost-effective, and ecofriendly technique for monitoring and mapping many geospatial natural resources and climate including forest, vegetation water dynamics and change monitoring, and biomass evaluations [1; 11; 6; 12; 13; 14]. Advanced and high-quality data acquisition and distribution facilities are offered by different space organizations, including the National Aeronautics and Space Administration (_NASA_), Canada Centre for Remote Science (_CCRS_) and the European Space Agency (_ESA_) [1; 15]. Generally, remote sensing techniques do not derive forest biomass directly but enable acquisition of parameters for forest biomass estimation, such as forest height, leaf area index, the fraction of vegetation cover (_FVC_), or net primary production.