Abstract: Based on the fractal theory, the adaptive cluster sampling technique for Nitraria tangtorum sand dune was studied by using the method of integrated remote sensing data and the actual survey data in Ulan Buh Desert. The linear regression equation for describing the relationship between perimeter and area of N. tangtorum sand dunes was established based on fractal theory. On the basis of the regression equation, the area of N. tangtorum sand dunes was estimated using perimeter and the prediction precision is 89.8%. Based on the estimated value of the area, effect of the adaptive cluster samples was analysed. The results showed that the precision of the adaptive cluster sampling can reach 96.9% and the relative efficiency of adaptive cluster sampling is 5.65 times of the simple sampling when the adaptability standard value (each plot area of N. tangtorum sand dune) is 50 m² which nearly equals the sample average value of the dune. The results will provide more effective inventory method for vegetation with cluster distributing in desert.

Key words: fractal, adaptive cluster sampling, Nitraria tangtorum, Ulan Buh Desert