Part of the transition to more symbiotic practices will involve improved technological efficiencies that can promote prosperity using less resources. Another part will involve changing from non-renewable or slowly renewable resources to quickly renewable ones. For example, fiber for paper and wood products now comes mainly from trees that take sixty to one-hundred years to grow. Trials are being undertaken to use fiber from hemp, which takes four months to grow. If feasible, such a shift would hopefully take less land, enable forests to be preserved and reforested, give a boost to agriculture, and provide abundant supplies of fiber for paper and wood products. Some environmental studies, such as that of the World Commission on Environment and Development (1987), place all their hopes on these technical solutions in order to reconcile ecological limits with economic growth.