The study was conducted to explore the sand and dust control effects by the protection forest system in Oasis from 1985 to 1987. The plot is located in the NO. 2 Experimental Field of Dengkou Experimental Bureau in the Inner Mongolia Autonomous Region of the Chinese Academy of Forestry, which is in the northeastern fringe of Ulanbho Desert and in the transition zone between desert and steppe.The results are as follows: 1. The Oasis Protetion Forest System established in the No 2 Experimental Field possesses great falling dust and sand-transporting control effects. 2. The main protective effects achieved within the networks of the protection forest are: (1) Angstrom turbidity coefficient βis reduced by 35-40%; (2) the amount of falling dust is decreased by 40%; (3) the amount of drifting sand is reduced by 80-90%; (4) the original structure of sand drift is changed. 3. As regards to the value of background turbidity, Angstrom turbidity coefficientβ of the region has already amounted to a very great
