Trees, the source of most paper products, are a renewable resource but take many years to replace. Although buying recycled paper gives trees a chance to grow back, not all recycled paper is the same. Look for paper with the highest possible post-consumer content. Post-consumer material has completed its life as a consumer item and has been discarded for disposal or recovery. Non-recycled paper products made from trees certified as sustainably harvested are also a good choice. This means that the forest has been well-managed, according to the criteria of established wood certifiers, such as the Forest Stewardship Council. Finally, Green Home recommends recycled paper that is processed without chlorine. Normal bleaching methods using chlorine compounds can create a variety of toxic or carcinogenic byproducts, such as dioxin and formaldehyde. These by-products turn up later in lakes and rivers.