(FORTUNE Magazine) – Looking for a backdoor play on the housing boom? Try timber companies, which not only grow and harvest trees but also supply lumber, plywood, and other wood products to builders. Two we like are Plum Creek Timber (PCL, $32) and Rayonier (RYN, $44). Both are organized as REITs and offer yields of more than 4%. Plum Creek is one of the largest timberland owners in the U.S., with about eight million acres in 20 states. Rayonier owns 2.2 million acres of timberland in the U.S. and New Zealand.

Both firms are now benefiting from the strong recovery in lumber prices. For years the industry was plagued by oversupply brought on by increased foreign imports. But imports have cooled recently because of the weakened dollar. Meanwhile, the demand from homebuilders for lumber and other wood products should continue.

Betting on timber is also a good way to diversify. Historically, its value is negatively correlated with stocks. That could help soften the blow during a downturn. --David Stires