Weyerhaeuser Company (NYSE: WY) is one of the largest integrated forest product companies, with annual revenues of nearly $5.53 billion in 2009. As an oft-cited example of vertical integration, Weyerhaeuser has businesses in timberland management, wood products, cellulose fiber, containerboard, and real estate. Cooperation between its segments allows the company to minimize transaction costs and to coordinate supply and demand internally.

However, despite these inter-segment synergies, Weyerhaeuser may decide to focus on its core timber business in restructuring efforts. In 2006, the company sold its fine paper business to Domtar, a Canadian pulp and paper company, giving Weyerhaeuser $1.35 billion in cash (used to pay off long-term accumulated debts) as well as stock in the newly merged company. There is speculation that Weyerhaeuser's possible future focus on the timberlands business is an effort to become a real estate investment trust (REIT), which would secure it significant tax benefits.

(Read more at Wikinvest )