Hardwoods in Green Building: Plantation-grown Eucalyptus Makes its Mark as a Versatile, Sustainable Exotic Species  

As concerns grow about climate change and other potential impacts on the human and natural environment, design professionals are increasingly challenged in specifying sustainable architectural materials. Hardwoods have always been popular choices in architectural finish applications due to their natural appeal, beauty, and durability. Yet concerns about deforestation and illegal logging - especially in tropical areas - have led designers to question the role of hardwoods in green building.

As an overall class of materials, wood products can play a significant role in helping reduce greenhouse gases in the atmosphere. The best way to ensure that trees - and hardwoods in particular - will provide for future generations is to select those woods that have been harvested according to sustainable forestry practices. This course will discuss sustainable forestry and other design issues to consider when selecting and specifying wood over other materials for architectural finishes. Also highlighted will be plantation-grown eucalyptus that has been certified by independent sustainable forestry programs as one type of increasingly popular hardwood that can help meet green building objectives.

Environmental Advantages of Wood Products

A primary advantage of wood in green building projects is that it comes from a renewable natural resource. Unlike petrochemicals used in making plastics and ores used to make aluminum, iron and other metals, trees obtained from plantations and forests that are properly managed can be harvested and replanted in subsequent cycles to help ensure a continuous supply, making wood one of the few truly renewable materials. In addition to its renewability, wood products have several obvious advantages over other types of building materials: they are non toxic, waste efficient, biodegradable and recyclable, and can make a contribution to combating global warming.

Sustainably grown hardwoods help reduce greenhouse gases in the atmosphere. Photo courtesy of Weyerhaeuser

Storage of Atmospheric Carbon Dioxide

Selection of wood products actually helps remove carbon dioxide, a key gas implicated in global warming, from the atmosphere. Through photosynthesis, growing trees absorb carbon dioxide from the air and convert it to carbon and oxygen. The carbon becomes an integral part of the wood fiber where it remains stored in long-lived wood products well after the lumber is harvested. The amount of stored carbon adds up considerably. According to the Canadian Woods Council, a typical 2,400-square-foot wood-framed home holds 7 tons of carbon (28 tons of carbon dioxide), equivalent to the emissions of a fuel efficient car over seven years. Since young forests capture more carbon dioxide than older, more mature forests whose growth rate has slowed, harvesting mature trees and regenerating naturally or with tree seedlings can increase the amount of carbon sequestered from the atmosphere.

Wood comes from a natural, renewable resource. Photo courtesy of Weyerhaeuser

 

Primary Energy Requirements

Numerous studies attest to the fact that wood requires substantially less energy to manufacture than alternative materials. According to the Consortium for Research on Renewable Industrial Materials (CORRIM), solid hardwood flooring requires about one-half the energy to produce as vinyl composition tile and less than one tenth the energy of wool carpet tile. 

CORRIM further found that compared to steel and concrete, wood-based building materials require less energy to produce, emit less air and water pollution, and result in lower amounts of CO2 to the atmosphere. CORRIM researchers found that compared to a wood framed house, a steel-framed home used 17 percent more energy; had 26 percent more global warming potential; had 14 percent more air emissions and more than 300 percent water emissions. The concrete-framed home used 16 percent more energy; had 31 percent more global warming potential; had 23 percent more air emissions; had roughly the same level of water emissions and produced 51 percent more solid waste.

Source: CORRIM

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."

Forest Certification Programs

Managed forests and plantations can help support sustainability goals, but not all managed forests or plantations are properly, or even legally, managed. According to the World Wildlife Fund, illegal logging practices result in the loss of nearly 36 million acres of natural forests across the world each year, an area roughly the size of New York State.

There is justifiably widespread concern about deforestation around the globe. Taking the Amazon basin as an example, 60 to 70 percent of deforestation comes from cattle ranching, and the rest from small scale subsistence. "Large-scale farming contributes relatively little to deforestation in the Amazon. And commercial forestry - logging followed by reforestation - is not deforestation," says Anderson. "However, studies do correlate unsustainable logging with future clearing for settlements and farming."

Chart courtesy of Rhett A. Butler/mongabay.com

 

The immediate challenge, says Anderson, is to combat illegal harvesting, poor forestry practices and over-exploitation that lead to deforestation. In the U.S., recent changes to federal law make it illegal to import, export, sell, acquire or purchase illegal or illegally acquired plants, including any plant illegally harvested and illegally harvested wood or wood products. In 2008, Congress amended the Lacey Act with the Combat Illegal Logging Act that helps combat illegal logging and promotes fair trade for legally sourced wood. The Lacey Act defines illegal wood as wood taken in violation of relevant laws in the source country, and holds the importing entity responsible for avoiding illegal wood.

In the 1990s, concern over forest conservation prompted the establishment of several different sustainable forest management standards. The differences between these standards were, and to some extent still are, a function of their origins. They were founded by different interests and tailored to national differences in government regulation. Over time, however, business realities and societal expectations have narrowed the differences. Many observers maintain that all major certification systems are credible standards for sustainable forestry. All have third-party certification procedures that validate a participant's compliance with the requirements in standards that are controlled by independent boards and all have representation from environmental organizations, forest products companies, and the wider forestry community and represent the environmental, social, and economic values required for sustainable practices. Generally, sustainable forest management standards also set rules for documenting the source of wood used in a product and the conditions under which a product can carry a certified product label.

The labels of forest certification schemes are showing up on more and more products every year. Certification provides design professionals with the assurance that the wood comes from responsible sources. Several creditable organizations worldwide address the unique environmental aspects of forests in both temperate and tropical climates. In tropical areas, there are three prominent certifying bodies: the Forest Stewardship Council (FSC); Programme for the Endorsement of Forest Certification (PEFC), and the Brazilian Forest Certification Program (CERFLOR), which is endorsed by PEFC. FSC and PEFC are umbrella programs operating around the world, with regional certification schemes, including ones specific to tropical areas and distinct subregions therein.

All three, however, are voluntary programs. They are designed to promote sustainable forestry practices and include measures addressing water quality, wildlife habitat, and threatened and endangered ecosystems, and all three programs call for harvesting and regenerating forests at sustainable levels. Critical to certifying programs is the chain of custody system that tracks the amount of wood from certified forests flowing into a mill, and the amount of certified labeled products coming out. Chain of custody does not usually mean that a certain piece of wood comes from a certified forest, but it ensures that certification labels accurately reflect the volume of wood coming from sustainable forests. "Certification is especially critical when specifying tropical hardwoods since many developing countries have historically had illegal or unsustainable logging," says Anderson, noting that building professionals can have a significant influence on the situation by specifying only those wood products that have been independently certified as coming from sustainable forests.

Certification by country

 

Yet even with this increase in promotion and demand for certified wood products, 90 percent of the world's forests have no certification at all - which makes it all the more important to source tropical wood that has been certified and/or comes from a company with operations that have been accredited to ISO 14001 standards. 

Eucalyptus  -  A Sustainable Exotic Hardwood

Eucalyptus is the most commonly planted fast-growing hardwood in the world with more than 700 species in existence. Because of their fast growth, plantation eucalyptus trees were traditionally harvested as a source of pulp for the manufacture of tissue, printing and specialty papers. With demand escalating for rapidly replenishing and attractive hardwoods, eucalyptus plantations are increasingly being managed to produce solid wood for architectural finish products. Although eucalyptus is native to Australia and grows in the U.S.; it is in the tropical and subtropical regions where eucalyptus is not only prolific but also exhibits the strength and durability required for architectural finish applications.

Brazil is the top producer and exporter of eucalyptus roundwood and pulp. It was introduced into the country in 1910 and has thrived in the local environment; today there are around 5 million hectares of planted eucalyptus in Brazil. The growth rate of eucalyptus is unprecedented, with trees reaching the size needed for lumber in 14 to 16 years, ensuring reliable supplies for the foreseeable future. Some eucalyptus plantations are 11 times more productive on a per hectare per year basis when compared to a temperate forest, which may take 80 to 100 years to mature. A eucalyptus plantation can produce 30 times the volume of lumber per hectare per year when compared to an unmanaged temperate forest.

The key to this productivity has been a substantial investment in technological improvements in tree cultivation and manufacturing. Plantation-grown eucalyptus trees can now be selected, pruned and milled to provide straight boards with fewer knots than trees from unmanaged forests. It is the manual pruning or "lifting," that maximizes the clear wood in each trunk - in other words, limbs are removed, enabling the growth of tall trees with few knots. Because the trees come into the mill in a clearer, more uniform state, there is a high conversion of logs to clear lumber.

Characteristics

Plantation-grown eucalyptus was used extensively throughout the Boulder Ridge Club House in San Jose. Photo courtesy of Boulder Ridge Country Club

There are many eucalyptus species, the most common of which is Eucalyptus Grandis. A popular product on the market is a natural hybrid of Eucalyptus Grandis and Eucalyptus Urophylla, which is harder than the common grandis and offers wider flitch widths and fewer defects than many other species. Despite its short growth period, this eucalyptus compares favorably to mahogany and other tropical and domestic hardwoods in terms of appearance and strength, and is often valued by design professionals for conveying the feel and style of a more expensive wood at an affordable cost.

In appearance, plantation-grown eucalyptus has a grain that is straight, even and moderately coarse and a rich pink color. It is increasingly seen as a more cost-effective alternative to mahogany, which is among the most expensive woods due to its 50- to 60-year maturation process and its status now as a rare and protected hardwood.

Glenda Garcia, General Manager of the Boulder Ridge Golf Club in San Jose, California,  a member of the International Furniture Designers Association and a Certified Designer in the state of California, selected plantation-grown eucalyptus for extensive use in the Craftsman-style clubhouse because of its similarity to mahogany and cherry. "The eucalyptus offered the widest range of colors, from a blond to walnut," says Garcia, who specified the wood for a variety of applications including interior walls, moldings, doors and the club bar. Lumber was shipped to out-of-state fabricators for the door and the bar. "We worked very hard on the stain color," says Garcia. "All the eucalyptus was hand-rubbed. It has a very warm feeling that people really respond to."

Eucalyptus is also becoming a replacement species for Brazilian cherry and kaya, which have been known to have questionable forestry practices. (Architects interested in keeping current on endangered timber species should consult the CITES lists on United Nations websites. In addition to Brazilian mahogany, some timbers to avoid due to their endangered status are: sapelee, wenge, ebony, and teak.)

Eucalyptus has a high strength-to-weight ratio and a hardness rating greater than white oak, mahogany, red oak, and is similar to hickory, hard maple or beech. Plantation-grown eucalyptus has a variety of working qualities that make it appropriate for interior applications. It has good machining and turning properties, without the "fuzzing" of mahogany. Eucalyptus also glues and holds fasteners well and sands to a smooth surface. With a relatively close grain, it takes all common types of finishing, including water and solution-based lacquers, various types of pigments, and oil and wax. All of these characteristics make the wood appropriate for diverse high-end applications like furniture, cabinets, flooring and architectural millwork products that are hardwearing. Eucalyptus is particularly well-suited to high-use interior situations as it maintains its appearance; it does not oxidize to a muddy brown as walnut does as it ages, nor does it fade like cherry.

The lumber of plantation-grown eucalyptus varies from red to light pink; the heartwood is a medium pink and the sapwood is paler. For customer convenience manufacturers may offer color sorting, in which they sort the lumber by color into three groups, say according to light, medium or dark pink. Most lumber yards tend to stock only one of the three tones depending on local preferences, assuring consistency in color.

Eucalyptus was used in the interior of the Ohana House in Hawaii Photo © Art Grice

Depending on the finish used, eucalyptus can be made to look like a temperate or tropical wood species and a light or dark effect achieved to complement a wide range of designs. In the Ohana House on the Big Island of Hawaii within a protected conservation zone, James Cutler FAIA of Cutler Anderson Architects, Bainbridge Island, Washington, specified eucalyptus finished with several coats of lacquer for the floors, casework and wall panels. The result is a crisp, honey-colored interior that is light and inviting. Cutler says that the firm always tries to use local materials, but that the native ohia was not long enough or available in quantity for this specific architectural application, so an imported eucalyptus hybrid was used. "We were drawn to the beauty of the wood," says Cutler. "It felt tropical and it was the right color to go with the lava rocks outside."

Traditionally, domestic eucalyptus has been known for its tendency to cup or warp. However, new methods of growing and harvesting the lumber have rectified the situation. Cutting the trees after 14 to 16 years of growth when they reach about 150 feet and have a diameter of 2 feet achieves the best results - superior to more quickly growing wood, and just as good as wood that takes longer to mature. Keeping the plantation grown eucalyptus straight enough to work is a function of many factors, beginning with careful handling when the tree is cut down and minimizing the time from harvest to opening up the log. The drying process is the single most important factor in keeping the wood straight and can involve air drying the lumber prior to kiln drying. The industry standard is to dry wood to 12 to 14 percent moisture content. Some eucalyptus manufacturers exceed that, drying lumber down to a 6 to 8 percent moisture content to assure a dimensionally stable product and to add value. In addition to being lighter and thus incurring reduced transportation and handling costs, dried timber is stronger than green timber; has better insulation properties; works, machines, finishes and glues better; and results in longer lasting finishes.

Applications of Eucalyptus

Eucalyptus is available in flooring, lumber and veneer for a wide range of residential and commercial applications. Manufacturers offer plantation-grown eucalyptus flooring in both solid strip lumber and engineered pieces. Solid strip eucalyptus flooring is harder than oak with the aesthetics of Brazilian cherry and typically costs less than walnut. Single-strip engineered flooring is made of a plywood base with a eucalyptus wear layer. As with solid flooring, some manufacturers offer tongue and groove construction, enabling it to be stapled, glued down or floated.

Photos and chart courtesy of Weyerhaeuser

Cabinets can be manufactured either from solid eucalyptus hardwood pieces or with veneers. Plantation grown eucalyptus is available as both flitches for custom applications and layons for plywood layup. Common characteristics of plantation-grown eucalyptus veneer are as follows:

Thickness: .6 mm (1/42 inch) and 1.6 mm (1/16 inch)
Width: 10 cm+ (3.9 inches +)
Length: 200 cm+ (78 inches+)
Grades: AA, A, B, C
Grain pattern: flat cut and quarters, with some specialty patterns available such as burl

Photos and chart courtesy of Weyerhaeuser

 

A consistent look was achieved with eucalyptus at Michigan State University�s Wharton Center for Performing Arts. Photo courtesy of TMP Architecture

The machining and turning properties of plantation-grown eucalyptus enable it to be used for a wide range of millwork from stair parts to columns to wainscoting and other architectural finishing applications.

For its $18.5 million, 24,000-square-foot expansion and renovation, Michigan State University's Wharton Center for Performing Arts chose plantation-grown eucalyptus for several applications including its donor wall, wooden cases and all the wooden doors in the four-story building. Laura Casai, IIDA, LEED AP, Interiors, TMP Architecture in Bloomfield Hills, Michigan, explains that while the project did not go for LEED certification, it was certainly LEED inspired. "The owner was interested in being as environmentally responsible as possible without directly going for LEED. Eucalyptus was a perfect solution given its striking resemblance to cherry in its darker range, and its rapid growth cycle. Its roughly fifteen years cycle is just shy of the ten needed to be considered ‘rapidly renewable' by LEED, but it is close," says Casai. "It was an interesting material and easy to work with," says Casai, noting that she oversaw multiple suppliers for veneer and hardwood pieces. "There was quite a range of color to the wood, but we were able to achieve a very consistent look," she adds.

Sustainability of Eucalyptus Plantations

While there is enthusiasm for the physical characteristics of plantation-grown eucalyptus, there are differing schools of thought on the sustainability of the plantations. Critics contend that fast-growing tree plantations can be detrimental to the environment, maintaining that uniform stands of the same species, particularly non-native species, do not provide appropriate wildlife habitats and they diminish soil and water resources. On the other hand, studies by Aracruz Celulose, a Brazilian pulp producer, in conjunction with universities, research centers, non governmental organizations and environmental agencies both inside Brazil and internationally, have found that when professionally managed, a eucalyptus crop does not degrade the soil or impact its physical, chemical, and biological characteristics. Some experts also counter that when it comes to sustainability not all plantations are created equal, and that the merits of a plantation should be judged on a case-by-case basis, with plantation planning having the capacity to mitigate potential problems. For example, significant areas of native vegetation that provide habitat for native fauna can be retained in areas that are wet, steep or rocky, or otherwise not conducive to commercial tree growing, and linked to wildlife corridors to connect with native species on surrounding lands. In Australia, the Victorian Arthur Rylah Institute for Environmental Research is studying birds and mammals in eucalyptus plantations, and has found that these plantations can have a positive effect on conserving biodiversity that is higher than open farmland, though lower than native forest.

In Brazil, highly productive eucalyptus plantations are sometimes interspersed with reintroduced indigenous trees, all within larger areas of native forest preserve-a strategy that helps create and maintain biodiversity and preserve native ecosystems. In some cases, more than 30 percent of these plantations are managed as permanent native forest dedicated to environmental protection. Brazilian eucalyptus plantations are often located on what was originally Brazilian rainforest, but was deforested for agriculture up to one hundred years ago. In many instances, original species native to the area a century ago have been reintroduced into this ecosystem.

Although eucalyptus is considered to be a tree with high water demand, Aracruz studies conducted have shown that water consumption of the plantation-grown eucalyptus trees was similar to that of native forests. From 1998 to 2004, evapotranspiration (average water consumption by eucalyptus) was 1,092 mm/year (or liters/m2/year) which is similar to the average amount of rainfall (1,147 mm/year) and approximately the same average consumption of the native forests (1,167 mm/year). Studies of other crops such as coffee, sugarcane, and citrus fruits show similar water consumption to that of the eucalyptus trees in the study area.

In terms of diminishing soil and water quality, an Aracruz nutrient balance survey during a complete eucalyptus crop cycle found that compared to geochemical surveys of agricultural areas in Europe and the United States, the flow of nutrients in the study area were low, due primarily to the small amount of nutrients required by eucalyptus in comparison with other crops. Nitrogen was the only nutrient with a slightly negative balance. To address this deficiency plantation owners can increase the amount of nitrogen applied in fertilizing to ensure its cycling through to maintain appropriate levels of organic matter. The study further found no relation between the fertilizer applied to the trees and the level of nutrients in the water bodies, nor any losses of applied nutrients to impact the quality of the streams and rivers.

Some eucalpytus plantations integrate native species to increase biodiversity. Photos courtesy of Weyerhaeuser

 

A 10-year study also by Aracruz that used birds as bioindicators of environmental quality in a eucalyptus plantation integrated with natural forest demonstrated a number of important considerations. Before the eucalyptus harvest, the watershed functioned as a forest environment, as demonstrated by the number of species that were spotted in both the remnants of the Atlantic Rainforest in the slope areas, as well as in the plantation stands. At the end of the wood cultivation/pulp cycle, a total of 85 species used resources that were encountered in both environments. Furthermore, individual birds of these species established their territories in the plantation stands, some of them hundreds of meters distant from the indigenous vegetation. Since birds only remain in locations where they are able to obtain food and protection from predators and climatic constrains, they bear witness to the use of local resources in eucalyptus stands and the associated understory of native species. Following the harvest, the native vegetation served to shelter these birds, maintaining local populations of the species. Once the denser growth of the plantation trees and understory appeared, the birds returned to the plantation areas. The study found that no species present before felling in the watershed disappeared from the commercial stands during the period following the eucalyptus harvest. Four bird species were discovered living entirely within the commercial plantations. A number of individual birds that had been banded before the felling of the watershed stands returned during the course of the new eucalyptus growth cycle. Others were absent during the first years after new planting, reappearing four years later.

Further, in the movement to re-colonize replanted stands or where eucalyptus stumps are regenerating, the birds also act as seed dispersal agents for a number of different plantation understory plants. In this way, they accelerate the restoration process of this vegetation layer under the eucalyptus canopy. This has the effect of restoring both the pre-harvest structure as well as the permanence of species that have adapted to the plantations and the associated understory. As a result, in areas where commercial stands are interspersed with native vegetation and dense understory, bird species have been shown to flourish.

Rating Systems

Design professionals specify certified wood to meet their own green building criteria or as part of earning points under designated green building certification programs. In the United States, three main building programs rate the green aspects of building programs: Green Globes, Leadership in Energy and Environmental Design (LEED), and the National Association of Home Builders National Green Building Program. As can be seen in the accompanying figure, all three rating systems award points for wood as a bio-based material, but vary in the types of certified wood they currently recognize. Currently, FSC certified products are the only certified wood products accepted by LEED, which is currently considering developing its own rating criteria. The NAHB standard recognizes all credible forest certification programs.

Chart: Weyerhaeuser

 

CONCLUSION: Hardwoods - A Viable Green Option

Given the environmental advantages of wood and the availability of third party sustainability certification, hardwoods - including tropical woods - can be a viable part of green building. As architects seek cost-effective, sustainable materials, properly sourced tropical woods like eucalyptus, which can be rapidly replenished, have the potential to provide an attractive, durable solution that is a replacement for other more expensive and possibly dwindling species.

Weyerhaeuser Company, one of the world's largest forest products companies, was incorporated in 1900. In 2008, sales were $8 billion. It has offices or operations in 10 countries, with customers worldwide. Weyerhaeuser is principally engaged in the growing and harvesting of timber; the manufacture, distribution and sale of forest products; and real estate construction and development. Additional information about Weyerhaeuser's businesses, products and practices is available at www.weyerhaeuser.com.