Assessment of the Effectiveness of Tree Shelterbelts in Controlling Wind Erosion in Kano State

Tree shelterbelts established in Nigeria's semi-arid North West zone as components of the Great Green Wall and state-level land rehabilitation programmes have received limited rigorous effectiveness evaluation despite significant ongoing public investment. This study assesses the effectiveness of tree shelterbelts in controlling wind erosion and modifying microclimatic conditions in the agricultural landscape of northern Kano State. A paired-site methodology compared wind speed profiles, soil loss rates, and crop yield outcomes between fields protected by established shelterbelts and comparable open fields at twelve locations across four Local Government Areas. Shelterbelt composition, age, canopy cover, and structural integrity were documented through field inventory. Aeolian sediment traps were deployed to quantify wind erosion at windward and leeward measurement points relative to shelterbelt positions. Farmer interviews at 90 households assessed perceived benefits of shelterbelts on crop performance and farm operating conditions. Findings confirm statistically significant wind speed reductions of 42 to 68 percent in the leeward protected zone extending to ten times the shelterbelt height, with concurrent reductions in aeolian sediment transport of 55 to 74 percent. Crop yields of millet and sorghum in protected zones average 28 percent higher than in unprotected fields with comparable management. However, 38 percent of surveyed shelterbelts show evidence of significant degradation through firewood harvesting and uncontrolled livestock browsing. The study recommends community stewardship contracts for shelterbelt maintenance, dedicated firewood supply programmes to reduce pressure on shelterbelts, and expansion of the shelterbelt programme to cover high-priority erosion-prone districts in southern Kano State. Keywords: shelterbelts, wind erosion control, Kano State, agroforestry, dryland management.