Response of annual ring width of Tamarix spp. to groundwater depth in the hinterland of the Taklimakan Desert

[Objective] Tamarix spp. is a typical species in the arid desert ecosystem, which is important to study the response of Tamarix spp. to groundwater for its protection. [Methods] Based on the data of groundwater depth in the Daliyaboyi oasis at the hinterland of the Taklimakan Desert, this study analyzed the variation of tree-ring width of Tamarix spp. and discussed the relationship between tree-ring width and groundwater depth. [Results] The groundwater depth of the first sample site was increased year by year, ranging from 1.2-2.6 m. Tree-ring width of T . spp. was increased significantly from 2001 to 2020 with a range of 0.98-5.80 mm at the first sample site, and the interannual difference of tree-ring width was significant. The range of the groundwater depth of the second sample site was 2.7-4.5 m, which was increased first and then decreased with time. The tree-ring width of T . spp. at the second sample site changed as a sine function from 1977 to 2020, ranging from 1.46 mm to 4.41 mm, with no significant interannual difference. The standard chronological amplitude of T . spp. was ranging from 0.502 to 1.641 at the first sample site, which was larger than the second site that was ranging from 0.577 to 1.331. [Conclusion] A moderate increase in groundwater depth was beneficial to T . spp. growth at the first sample site, supported by the increase of tree-ring width. There was no significant correlation between treering width and groundwater depth at the second sample site. These results are helpful to understand the radial growth of T . spp. with the changes in groundwater depth.