Abstract:

In order to explore the importance of the complete structure of the forest belt on the windward side of the windbreak and sand-fixing forest to the law of wind-sand activity， this study used the wind tunnel test to analyze the windbreak effect， sand transport rate， sand fixation effect and sand accumulation form of the structurally complete forest belt and the structurally incomplete forest belt （discrete type missing 1-5 plants， continuous type missing 3/2H-7/2H， broken belt 1/2H-5/2H） under the wind speed of 12 m·s^-1. The results showed that： （1） With the weakening of the structural integrity of the forest belt， the windbreak effect and sand fixation effect of the forest belt decreased， while the wind erosion amount and wind erosion range increased. When the number of missing trees ≥5， the distance of missing trees ≥3H， and the distance of broken belts ≥3/2H， the windbreak effect <25% （H is the height of the plant model）， the sand fixation effect is weakened by 107.42%-291.48%， and the wind erosion amount is increased by more than 200% compared with the complete forest belt， and the wind erosion range accounts for more than 50%. The interception effect of the forest belt on wind-sand activity is weakened and the wind erosion effect on the windward forest belt is increased. That is to say， the proportion of missing plants in the windward side of the field is ≥25%， the distance of missing plants is ≥6 m， and the distance of broken belts is ≥3 m. Timely replanting and reinforcement measures should be taken.

Key words: windbreak and sand-fixing forest, structural integrity of forest belt, wind tunnel simulation, windproof and sand-fixing ability