Experimental study on the effect of plant spacing, number of rows and arrangement on the airflow field of forest belt in a wind tunnel

Forest belts play an important role in soil wind erosion control and the prevention of aeolian sand movement in arid and semiarid regions. In order to reveal the effect of plant spacing, number of rows, and arrangement on airflow of forest belt, the airflow fields were measured in a wind tunnel for artificial single-row forest belts with different plant spacings, forest belts with different numbers of rows with the same plant spacing, and two rows of forest belts with different arrangements. The results indicate that for the single-row forest belt, the downwind airflow decreases in the canopy area and then recovers exponentially. As the plant spacing increases, the characteristic length of the downwind airflow recovery of the forest belt and the distance at which the minimum wind speed is located both decrease approximately exponentially. As the number of rows in a forest belt increases, the downwind airflow speed in the canopy area decreases. The average reduction of downwind relative wind speed decreases with plant spacing and increases with the number of rows. A forest belt with staggered arrangement has lower downwind speeds and a longer characteristic length of airflow recovery than that in rectangular arrangements.