Material Utilization

The forest products industry uses virtually every portion of the log. Byproducts of converting a log to lumber - sawdust, bark, chips and slabs - have nearly a 100 percent utilization rate. Bark and sawdust may be used as bedding materials for nursery use, chips for paper-making processes, or wood fiber converted to plywood. Other wood byproducts are burned and converted to energy, with some manufacturers able to produce sufficient electricity to power their operations using residuals as bioenergy for heating on-site boilers for conditioning and drying processes. According to the Virginia Department of Forestry, the forest products industry consumes enough of its own by-products to save over 2 million barrels of oil annually.

Recycling

Because building construction uses large quantities of materials, considering recyclability and recycled content during product specification can help make more efficient use of raw materials and minimize waste going to landfills. While wood has not been a primary recycled material in the past, building professionals are paying closer attention to how it can be reused. Architectural finishing materials can often be salvaged from demolished buildings and recovered wood can be used to manufacture new products such as medium-density fiberboard and particle board or if untreated converted into mulch or used as fuel to help conserve other natural resources.

At the end of life, wood products are used in various ways:
8 percent is composted; 9 percent is recovered for reuse; 14 percent is burned for fuel; and 69 percent goes to landfills or dumps. Once in a landfill, only 23 percent of the stored carbon is estimated to be emitted over time; the remainder represents a landfill sink of carbon.

Managing Forests for Sustainable Supply

While the advantages of wood products are clear, where and how the wood is obtained ultimately determines its credibility as an environmentally sound building product. Basically, there are three forest types.

Protected forests. National parks or wilderness areas are protected areas and are not intended to produce forest products. These lands remain as protected forests to promote biological diversity, recreation, and other social and environmental values.

Wood-supplying forests. Among forests managed to supply wood, some are sustainably managed and some are not. Forests relying on natural regeneration can be sustainably managed, but timber harvesting in these natural forests can also be exploitative and not sustainable. An unsustainable forest is one in which the rate of removal of wood exceeds that of either the natural regeneration or replanting of trees. Sustainable forests are those in which trees are harvested, replanted or left to naturally regenerate, and managed over their life to ensure vibrant and healthy growth. This category of forest is managed to maintain more natural qualities, both to meet global needs for wood and to sustain local communities.

Intensely cultivated forests. A third type is a forest or tree plantation that is intensively cultivated, harvested and replanted to maximize the volume of wood produced, using tree planting or other practices derived from agriculture to grow high quality wood quickly and renewably. By enhancing the annual wood yield from each acre of land, managed forests and plantations reduce the footprint needed to produce wood products. The enhanced yield is a function of several factors: trees bred for both quality and growth; managed tree spacing and density that optimize wood growth and quality, and replanting trees, which speeds regeneration dramatically over seed fall. Also, by focusing growth and harvesting in specific, planned areas, tree plantations can minimize adverse impacts to environmentally sensitive areas such as waterways and steep slopes and protect wildlife habitat. 

Each type of forest has its own carbon implications. In a protected forest, trees store carbon as they grow and eventually mature, die and decompose, which releases their trapped carbon back into the atmosphere. Over their full life cycle, trees are carbon neutral. In a managed forest, the harvested trees are converted into wood products, a portion of which store carbon long-term, making them net sequestering or carbon positive. An intensively managed forest like a plantation removes larger amounts of carbon dioxide from the atmosphere than a slower growing forest. The shorter harvest intervals increase the volume of wood produced, providing a greater amount of carbon storage capacity in finished wood products.

"There is a vision emerging among governments and nongovernmental organizations that the best way to sustain forest resources globally is through a balance of these three approaches," says Eric Anderson of Weyerhaeuser Forestlands International. "The idea is to manage plantations intensively to produce as much wood and fiber as possible while protecting the environment. This relieves pressure on the other two types of forest even as the demand for wood and wood products continues to grow."