Depending on their size, density, and placement, trees can either decelerate or accelerate wind. Trees also create turbulence in the prevailing wind flow, which reduces the efficiency of the wind turbine. To maximize turbine efficiency, there should be no obstructions to prevailing wind flow within a considerable distance of the turbine. Therefore, tall-growing trees must be kept a sufficient distance away from the turbine in the prevailing wind direction. If trees are desired in the vicinity of the turbine, small-stature species that stay short, even at maturity, should be used. Planting trees to accelerate wind near a turbine is impractical because the wind flowing across vegetation will become turbulent and reduce the efficiency of the wind turbine.