A review on biomass estimation methods using synthetic aperture radar data

Due to the important role of forests in the global carbon cycle, it's necessary to pay more attention to these regions. Among forests biophysical parameters, Biomass estimation as the most influencing factor on the ecosystem is the most important. Due to limitations of traditional forest inventory technique to measure biomass, remote sensing has been widely used for biomass estimation in the past decade. In areas with complex structure, various species and multilayer vegetation cover, using microwave images would be the only solution because of the limitation of optical images. According to recent studies about biomass estimation with microwave images, the interferometry technique yields the best results but still is limited and not tested in all forest types. Because using microwave images has its own problems, focusing on the development of the new approaches which can handle multi source data, identify and decrease uncertainty sources in biomass estimation is required in future studies.