Engineered Wood and the Environment: Facts & Figures
The folklore notion of the flannel-shirt-clad lumberjack chopping his way through forests persists in the minds of many. But the reality has changed by leaps and bounds since Paul Bunyan's days. The modern forest industry has sustainable forestry down to a science, embracing wood's environmental merits without depleting the resource. Consider the following facts and figures.
Forest Growth Exceeds Harvest
Contrary to popular belief, we're not running out of trees. In fact, forest growth in the U.S. has continually exceeded harvest since the 1940s. The geographic area that encompasses the United States today has a greater extent of forest cover—one-third of the land mass—than it did in 1920. Indeed, American landowners plant more than 2 billion trees every year, and many more seed naturally. The forest products industry, which comprises about 15 percent of forestland ownership, is responsible for 41 percent of all replanted forest acreage. That works out to more than 1 billion trees a year, or about 3 million trees planted every day. Trees flourish in Canada as well, where forests cover half of the land mass and the replanting record continues to be strong.
Renewability Completes Natural Cycle
Wood is the only naturally renewable building material, and that cycle of growth has an added benefit. When a young forest is growing, it produces 1.07 tons of oxygen and absorbs 1.47 tons of carbon dioxide for every ton of wood. But as the forest matures, growth slows, and the absorption rate drops off. Harvesting a mature forest sequesters the carbon in the wood, meaning it will not be released into the atmosphere. A 2,400-square-foot wood-frame house, for example, has 28.5 tons of carbon dioxide sequestered, roughly equivalent to seven years' worth of emissions from a small, light-duty car. Harvesting mature forests also allows new, young forests with a rapid rate of carbon absorption to take their places, continuing the naturally perfected cycle.
Sustainable Forestry Encourages Growth
Private forest owners ensure that quality land management, including aggressive reforestation efforts, will keep their business going in the future. But if demand for wood falls off, private landowners might replace the forests with a crop in higher demand, reducing the environmental benefits a growing forest produces in our ecosystem. Demand for wood products keeps our forests growing; it does not eliminate them.
Technology Improves Manufacturing Efficiency
Technological innovations continue to dramatically improve the efficiency of wood product manufacturing. Modern sawmills produce more than twice the amount of usable lumber and other products per log than they could a century ago. Technological advances have increased the industrial output per unit of wood input 40 percent in the last 50 years. Modern technology can assure the quality of the product before it leaves the production line.
Engineered Wood Maximizes Resource
Engineered wood products make far more efficient use of the available resource today than ever before. Engineered wood can be manufactured from fast growing, underutilized, and less expensive wood species grown in privately managed forests. That helps safeguard older forests that as a society we have chosen to preserve. Byproducts from other production processes—small chips or unusable bits of wood—can be recycled and reused in engineered wood products. Engineered wood also eliminates many of the defects found naturally in wood, thereby improving upon many of the material's inherent structural advantages.
Wood Offers More Product for Less Energy
Simply put, manufacturing wood is energy efficient. Compare the amount of energy it takes to produce one ton of cement, glass, steel, or aluminum to one ton of wood:
- 5 times more energy for one ton of cement
- 14 times more energy for one ton of glass
- 24 times more energy for one ton of steel
- 126 times more energy for one ton of aluminum
Wood products make up 47% of all industrial raw materials manufactured in the United States, yet consume only 4% of the total energy needed to manufacture all industrial raw materials. Wood's manufacturing process alone makes it the environmentally friendly choice in building materials.
Green Building Fact Sheets:
• Trends in Wood Buildings (213 KB PDF)
• Wood and Green Building - Why using wood from North American forests is a sustainable choice (217 KB PDF)
• U.S. Wood Products - Good for jobs, rural communities and the environment (220 KB PDF)
CORRIM (Consortium for Research on Renewable Industrial Materials) fact sheets:
• Maximizing Forest Contributions to Carbon Mitigation, Fact sheet 5 (416 KB PDF)
• Product and Process Environmental Improvement Analysis for Buildings, Fact sheet 6 (166 KB PDF)
Wood and Green Building fact sheets produced by the Wood Promotion Network:
• LEED® vs. Green Globes™, Form WP G330 (778 KB PDF)
• Home Builder Guidelines, Form WP G335 (769 KB PDF)
• The Role of Life Cycle Assessment, Form WP G340 (901 KB PDF)
• Using Wood to Fight Climate Change, Form WP G345 (773 KB PDF)
Wood: Sustainable Building Solutions, Form F305 (3 Mb)