A steelframed 2 by 4 wall with R12 fiberglass bats has an overall Rvalue of only 6 to 6.85, while a wood 2 by 4 wall has an overall Rvalue of about 10.9. Wood is the only building material derived from a renewable resource. It is considered an agricultural crop that is harvested and replanted in a continually regenerating cycle while nonrenewable resources such as iron ore are mined on a permanently depleting basis. A 1976 study by the National Research Council committee on Renewable Resources concluded that producing 1 Ton of steel requires 50.3 million BTU oil equivalent, compared to 2.9 million BTU oil equivalent for 1 Ton of softwood lumber. A 1991 U.S. EPA listing of toxic substances released and transferred in the manufacturing process, indicated primary metals at 757 million pounds, fabricated metals at 103 million pounds, plastics at 195 million pounds, petroleum at 103 million pounds and wood at 38 million pounds.
Trees are a renewable resource.
Forest products are also recyclable and biodegradable. We sometimes forget that wood is naturally reusable, recyclable and biodegradable. It is the best insulator of all structural building materials, thus conserving finite fossil fuels and coal by requiring less energy to heat and cool a home built with wood. One mature tree absorbs approximately 13 pounds of carbon dioxide per year. For every ton of wood a forest grows, it removes 1.47 tons of carbon dioxide and produces 1.07 tons of oxygen.