Weyerhaeuser primarily grows and harvests trees, develops residential lots and builds homes, and makes a range of forest products. It manages 22 million acres of forests and generated $8 billion in net sales in 2008. Through the first nine months of 2009 it has generated just over $4 billion in sales, 35% behind the same 2008 period.

"This conversion will position us to be more competitive in our timberlands business," Dan Fulton, president and CEO, said in a statement.

A REIT distributes at least 90% of its taxable income to shareholders as dividends each year and then deducts those dividends from its corporate taxable income. If it distributes 100% of its taxable income it would owe no corporate income tax. Weyerhaeuser's current income tax rate is 35%.