Diesel fuel, much like cold, hard, cash, is a rare and precious resource.

And, much like money, it doesn't grow on trees... Or does it?

Amazingly, it's true: The Copaifera langsdorffii, or so-called "diesel tree," from Brazil produces a form of oil that can be used to power both cars and farm equipment. A single hectare crop (approximately 2.5 acres) can provide 12,000 liters of oil each year: enough to fuel all the equipment on a standard family's farm.

So why aren't we all growing these trees in our backyards, using their natural diesel to fuel our cars and trucks, rather than relying on Mobil or Exxon? Well, for one thing, you'd be waiting quite a while to fill your tank: These trees don't start to produce significant amounts of oil until after decades of growth.

"Principally, they are an ideal plantation tree for a family farm where, from generation to generation, you will harvest this oil so that your grandson and your great-grandson can still be virtually getting free fuel from these trees 30 to 50 years in the future," Mike Jubow, a nursery wholesaler from Queensland, Australia, told the Australian Broadcasting Corporation.

Fortunately, plenty of farmers have realized that helping the planet is worth waiting for: Jubow is selling about 20,000 of the diesel trees each year to farmers around Queensland. Eventually, if the owners decide to chop down the trees, "you've got plantation-grown timber, which is a very high-grade timber that is suitable for cabinet-making," said Jubow.

Free fuel and kitchen cabinets, all in one? You won't see a deal like that at your local Shell station.