Virtual timber

Plum Creek Timber (PCL) owns 8.2 million acres of timber in 18 states. Divide the market cap by the acres and you get about $900 per acre. Cheap land, professionally managed, 4% dividend. Land and timber are hard assets, so they should stay even with inflation, plus GDP growth. You're diversified across 18 states, so there's less risk from natural disasters.

But wait, there's more! If the price of lumber goes down (can you say "real estate bubble"?), management can always just... do nothing. The trees will keep growing, and when the price of lumber goes back up, the trees will be bigger. As opposed to corn, which will rot in the fields if it isn't harvested. The only downside is that there is no specific acreage that you can walk on, no actual trees that you can hug.

All in all, and over the long term, virtual timber should provide a return comparable to that of stocks. PCL, a single company, is riskier than a broad-based index like the S&P 500, but a little bit of PCL should reduce overall portfolio risk.

Disclosure: I do own a few acres of virtual timber.