Land degradation and drought result in food shortage and malnutrition in people in Sahel region, West Africa. This paper clarify Hausa farmers' strategies to overcome ecological vulnerabilities based on their local ecological knowledge of tree species and shapes. Hausa people recognise tree shapes by eyesight and classify them into the following four categories: laubu, barau, matasi, and mayanci, in Hausa language. Laubu indicates small saplings, younger than one year, whose lower branches are not cut. Barau indicates over two-year-old trees, whose branches are neither cut nor pollarded. Matasi represents small trees with pollarded branches. Mayanci represents big-trunk trees that are taller than millets. Laubu and barau are used for accumulating sand and preventing land degradation. Matasi is intended for crop protection from wind and solar heat. Mayanci provides shade for livestock and people. It also provides food for humans and fodder for livestock. The local farmers have ecological knowledge to manage forests by tree shape. They have innovative uses of trees for their millet fields, based on the soil condition and yield of their fields.