Productivity and carbon sequestration of Populus euphratica at the Amu River, Turkmenistan.

摘要

Deserts belong to the least productive terrestrial ecosystems, but along rivers, they may exhibit a high productivity. In central Asia, Populus euphratica Oliv. is the dominant tree species of the riparian 'Tugai' vegetation. In terms of climate change mitigation, 'Tugai' restoration may be traded for on the international carbon market. However, detailed knowledge of 'Tugai' productivity is lacking. Within this study, we modelled the productivity of P. euphratica based on tree-ring data (r2=0.73, P0.001) and applied the derived model to estimate the stand productivity of this species within the Kabakly nature reserve on the Amu River, Turkmenistan. Productivity estimates ranged from 0.3 to 3.0 t ha-1 year-1 and expressed the same magnitude as the data mentioned previously in the literature. Forest productivity appeared to be negatively correlated with distance from the river, which was consistent with Quickbird remote sensing data. Quickbird net differenced vegetation index (NDVI) was strongly correlated with Landsat NDVI (r=0.91, P<0.001), indicating the general potential to upscale net primary productivity estimates for P. euphratica. Tree ring series expressed no synchrony, for which possible explanations are discussed. Under ideal conditions P. euphratica sequesters CO₂ and thus may be considered a suitable tree species for carbon trade mechanisms and climate change mitigation.