Abstract: The morphological features of [WTBX]Tamarix ramosissima[WTBZ] nebkhas in three different sample plots in the internal, central and peripheral areas of the oasisdesert ecotone in Qira, Xinjiang were investigated. The relationships among the morphological parameters, spatial distribution pattern and corresponding variation were quantitatively analyzed. The results are as follows: ① The [WTBX]Tamarix ramosissima[WTBZ] nebkhases were convex and semiellipticalshaped, and they were covered with thickets. The values of nebkhas height and volume and crown area of [WTBX]T. ramosissima[WTBZ] varied in ranges of 0.27-3.21 m, 0.30-291.63 m3 and 2.39-128.76 m2 respectively. From the internal area to the peripheral area of the oasisdesert ecotone, the scale of nebkhas became larger, and the thickets grew luxuriantly;② There were the significant correlations among the morphological parameters of nebkhas. Among them the significant regression relationships between nebkhas length and width, nebkhas area and height changed gradually from linear relation to quadratic function for the nebkhases from the internal area to the peripheral area of the ecotone. There was a significant linear relationship between the crown area of [WTBX]T.ramosissima[WTBZ] and the nebkhas; ③ From the internal area to the peripheral area of the oasisdesert ecotone, the nebkhas density reduced, the spatial distribution pattern of nebkhas changed from aggregation to random pattern at spatial scale of 100-250 m, and the aggregation degree decreased. The nebkhases are currently still at growing stage, and it was considered that the formation and development of nebkhas is caused by land degradation.

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