Forests provide immense economic benefits. They are a source of timber and wood as well as non-timber products like rubber, cotton, and medicinal products. Fuel wood and fodder from forests are especially important for developing nations where people rely on wood for household energy. However, the growing demand for commercial timber and other forest products coupled with a rising population is resulting in overharvesting of forests and a shortage of tropical hardwoods. Forests also accumulate large amounts of biomass and represent stores of potential energy. Disturbances like fires and tree falls radically alter the environment, while the rapid growth of trees also induces environmental changes at a slower pace.