Spatial distribution and carbon stock of the Saxaul vegetation of the winter-cold deserts of Middle Asia

Carbon stocks and carbon accumulation in the earth's drylands have gained increasing attention. The winter-cold deserts of Middle Asia, i.e. in Kazakhstan, Uzbekistan, and Turkmenistan, cover an area of 2.5 million km2. Within these deserts, the two Saxaul species White Saxaul (Haloxylon persicum Bunge ex Boiss. & Buhse) and Black Saxaul (Haloxylon aphyllum (Minkw.) Iljin) are dominant woody species with a potential distribution area of about 500,000 km2. From the 1950s until today, the Saxaul vegetation has been degraded through logging and over-grazing. In this paper, we estimate the current and potential living above ground and below ground biomass of the Saxaul vegetation and its carbon stock. The living above ground biomass ranges between 1.5 t/ha and 3 t/ha. The potential carbon stocks above ground and below ground amount to 29.4–52.1 million t and 22–81.4 million t, respectively. Today, only 11%–28% of the potential biomass and carbon stock have remained. The carbon stock of the Saxaul vegetation is low compared to other ecosystems of the earth, but restoration and conservation of Saxaul vegetation is one way to sequester carbon through vegetation for Uzbekistan and Turkmenistan, which do not have much other woody vegetation. ► We estimate the potential biomass and carbon stock of Saxaul deserts in Middle Asia. ► The above ground biomass ranges mostly between 1.5 t/ha and 3 t/ha. ► The potential above ground carbon stock is 29.4–52.1 million t. ► The potential below ground carbon stock is 22–81.4 million t. ► Today, only 11%–28% of the biomass of the potential Saxaul deserts have remained.