[Objective] To study the windproof efficiency of shelterbelt composed by Haloxylon ammodendron and Caragana korshinskii and its response to wind directions in order to provide theoretical basis for shelterbelt construction on the periphery of desert oasis

desert road and desert railway.[Methods] Prototypes of H. ammodendron and C. korshinskii with different individual characteristics were used to make simulation plants

and then constructed into high-low shelterbelt

which was recorded as AmBn pattern. Here

the capital letter "A" represented the simulated plant H. ammodendron

"m" represented that the planting space was 15 cm×40 cm

the capital letter "B" represented the simulated plant C. korshinskii

and "n" represented that the planting space was 8.5 cm×25 cm. When the wind direction was opposite

the shelterbelt was recorded as BnAm pattern. By the wind tunnel simulation experiments

the airflow field

wind speed acceleration rates and the windproof efficiency were analyzed with the controlled wind speed of 7

10

15 m/s.[Results] ① When the airflow reached to the front of the shelterbelt

the wind speed decreased overall. According to the variation intensity of wind speed

the air flow could be divided into 3 layers:the upper layer (above the 30 cm)

the middle layer (5-20 cm)

and the lower layer (below 3 cm). The speed recover point behind the shelterbelt in AmBn pattern and BnAm pattern was 23 H and 12.5 H

respectively. ② The wind shadow range of AmBn pattern was greater than that of BnAm pattern. The wind shadow core areas were formed at the canopy height of both "A" plant and "B" plant

namely

a dicaryon pattern was formed. ③ Under the controlling wind speed of 7

10

15 m/s

the average windproof efficiency of shelterbelt AmBn was 34.44%

34.98% and 32.51%

respectively. The average windproof efficiency of shelterbelt BnAm was 22.62%

19.70%

19.41%

respectively. ④ In vertical direction

the forest belt played a role in slowing down the airflow below the height range of about 1.5 H

which accelerated the airflow above this range. In the horizontal direction

the windbreak efficiency of the AmBn type forest belt was better than that of the BnAm type forest belt before

within and after the belt.[Conclusion] The windproof efficiency of shelterbelts is related to the occurrence order of the plants along the wind direction. In view of the protection efficiency and protection distance

the shelterbelt in AmBn pattern is suggested to be constructed.