Scale-Compatible Aboveground Biomass Estimation Using Canopy Cover: Evidence from the Gobi Desert of Northwest China

Multiple morphological factors of desert plants were employed to construct aboveground biomass (AGB) estimation models in the Gobi Desert, located in the northwestern part of Gansu Province, China, where gravel surfaces account for more than half the area. At the individual scale, estimation models incorporating variables related to canopy cover accurately estimated AGB (R2 = 0.623~0.848). At the quadrat scale, the cover-allometric model effectively estimated multi-species AGB (AGB = 0.302 × Ct0.900, R2 = 0.725). At the regional scale, the model incorporating relative canopy cover was effective for estimating aboveground biomass density (AGBD) and could be combined with regional area estimates to determine the AGB of desert plants at any spatial scale (AGBD = 20.114 × Cr1.043, R2 = 0.8313). AGB estimation models based on canopy cover not only overcome scale limitations but also exhibit a tendency toward improved model fit with increasing scales. However, when applied to remote-sensing data, the model exhibits relatively low fitting accuracy (AGBD = 4.398 × Cr0.538, R2 = 0.3656). It demonstrates good stability when applied to Gobi Desert habitats similar to the study area, but its applicability in other arid regions still requires further validation.