Forestation is a widely accepted way to combat desertification. This approach can have tremendous beneficial effects on soil and environment. The United Nations Food and Agriculture Organization recommended Acacia victoriae for rehabilitation of degraded arid environments. For that purpose areas in the Northern Negev were planted with Acacia victoriae in the period of 1990–1993. The planting techniques were: sparse plantings (Contour trenching and Savanna), and dense planting of woodland. We divided each of those treatments into planted and control plots. In the plots planted by contour trenching the values of annual biomass per area, nutrient and Soil Organic Carbon (SOC) contents underneath the tree's canopies were the lowest, while those values in the planted savanna and woodland plots were significantly higher. Contour trenching also harmed the soil by causing erosion, and decreasing the soils water holding capacity. Therefore, Woodland and Savanna plantings should be preferred over contour trenching in arid areas.