Morphological characteristics of tree shelterbelts and their impact on wind regimes, air temperature and soil quality

Abstract

The morphological characteristics of different shelterbelts can give a definite clue about their efficiency for providing sheltered area on their downwind sides and thus minimizing hazardous effects of wind and creating favorable micro-environment for farm crops. The effect of Acacia tortilis, Eucalyptus camaldulensis, Dalbergia sissoo, Tecomella undulata shelterbelts varying in their morphological characters was assessed on wind regimes, air temperature and soil properties in arid Western Rajasthan. The findings revealed that in comparison to upwind reference, all the shelterbelts caused maximum reduction (21.5 to 36.0%) in wind speed on downwind side at a distance of 2H (H is average height of shelterbelt). The reduction was more pronounced between 2H and 10H, and slowly nullified up to 20H. On an average, more reduction in speed of upwind was caused by double-row shelterbelts, however, single-row belts provided more sheltered area on lee side. Minimum wind turbulence at the ends was provided by the shelterbelts having maximum L/H ratio. The porosity played overriding role in deciding sheltered area on downwind side as well as tunneling effects at the ends. Besides reducing speed of wind, presence of shelterbelts also enhanced soil organic carbon and reduced daily air temperature in sheltered area. The enrichment of soil and moderation of micro-environment on downwind side was more pronounced up to distance of 5H. Fairly tall (~10m) and dense (double-row) shelterbelts having length and height (L/H) ratio of 10 to13 were most suitable and efficient in providing protection against wind hazards.