When renovating or remodeling, sourcing products and materials from ecologically wise sources, maximizes energy efficiency, reduces waste, and promotes a healthy environment. Green building materials include renewable plant materials like bamboo and straw, lumber from forests certified to be sustainably managed, recycled stone, recycled metal, and other products that are non-toxic, reusable, renewable, and or recyclable. There are many green building resources and materials available locally, resale and wholesale, through consultants, contractors, city offices and non-profit groups that increase efficiency of resources — energy, water, and materials — while reducing building impacts on human health and the environment during the building's lifecycle.