Trees reduce the effect of erosive forces using their root systems and foliage. Tree roots begin as thick stems that branch into fine filaments to create a network of flexible tendrils that help stabilize the soil around the tree and hold it in place. The leaves and branches of trees create a flexible screen that reduces the force of wind and rain in the surrounding area. You can increase the beneficial impact of trees on areas with eroding soils by planting them in groups.Wind and rain are two of the main forces that erode bare soil. Droplets of rain water gain momentum as they fall which provides enough force to move particles of dirt when they reach the ground. Rain trapped on the surface of the soil can carry loose soil particles downhill under the influence of gravity. This problem is exacerbated in areas of bare soil since the soil is exposed to full force of wind and rain. Bare areas exposed to strong winds can lose significant amounts of soil if the ground is dry and there are no roots present to hold the soil in place.