Abstract
Forests are essential for regulating global carbon balance, controlling the rise of greenhouse gas concentrations in the atmosphere, protecting biodiversity, and ensuring a stable global climate. Quantification of forest biomass is imperative to comprehend forest carbon cycling, resource development, and carbon storage estimates. The measurement, monitoring, and evaluation of forest aboveground biomass (AGB) have now become a growing area of interest for researchers worldwide. Moreover, it is critical to employ a proper and rigorous method to accurately assess forest biomass. The methodologies for AGB estimations of forest trees are covered in this chapter. Traditional ground-based techniques are described, including a destructive approach that necessitates tree felling and a nondestructive approach for AGB calculations. Although the conventional traditional destructive approach is seen to be the most precise and dependable approach, it is also the most time- and money-consuming, difficult, and cannot be used to cover vast regions. Nondestructive traditional techniques also take up a lot of time and resources. Allometric equations-based indirect methods of AGB estimations are established by relating AGB to various forest characteristics, including diameter at breast height and height of forest tree and are less time- and money-consuming. Geospatial approaches are also extensively used by researchers for estimating AGB of forest trees. This technique allows accurate spatiotemporal quantification of AGB and is both cost- and time-effective. It can be used to estimate AGB for sizable forest areas. For AGB estimations, a variety of geospatial data, including optical, microwave, combined optical and microwave, hyperspectral, light detection and ranging, drones, and unmanned aerial vehicles, are extensively investigated.