Pine trees aren't viewed as food sources in these parts, but the nuts of the pine tree have been a valuable food source for millennia across the American southwest, Asia, Europe and Africa.

Pine nuts grow inside the pine cones; all pines have them, but many pine species have nuts too small to bother with. Harvesting and shelling the nuts is a lengthy process, driving up their cost to more than $20 a pound.

The cost varies with the source of the nuts. Mediterranean, Italian and New Mexican pinon pines deliver a sought-after premium pine nut, about a half-inch long, with a milder flavor. Cheaper Chinese pine nuts are shorter, shaped more like a stubby triangle, and sometimes packa pronounced pine sap flavor.

Classic pine nut dishes like pesto could have their flavor changed by nuts that taste like your Christmas tree smells, so check which kind you're getting.

Accept substitutes: If you run out of pine nuts or don't want to splurge on the little dears, you can use almonds or walnuts instead. The taste will be close enough for most palates.

Freezer friendly: The high fat content of pine nuts puts them at risk of turning rancid. In an airtight container, they can be safely refrigerated for about three months, or frozen for nine.

Here, pesto made with the traditional pine nuts anchors a Genoese classic in this Mark Bittman recipe. The pesto loses some punch when it's reheated, so try to get enough people together to enjoy this filling but flavorful dish.

>Pesto with Green Beans and Potatoes


2 cups fresh basil leaves

2 garlic cloves, peeled

1/2 cup grated pecorino Romano or Parmigiano-Reggiano

1/2 cup extra virgin olive oil, or more

2 tablespoons pine nuts

2 medium potatoes, preferably boiling potatoes

1 pound linguine or trenette

1/2 pound green beans, trimmed and cut into 1-inch lengths

Bring large pot of water to boil, and salt it. Peel potatoes and cut into 1-inch chunks.

Combine basil, garlic, salt to taste and cheese in blender or food processor. Pulse until roughly chopped. Add oil in a steady thin stream while blending until mixture is creamy, adding a little more oil or water if necessary. Add pine nuts and pulse a few times to chop them into the sauce.

Add potatoes to boiling water and stir, then add pasta and cook as usual, stirring frequently, about 10 minutes. When pasta is about half done -- strands will bend but are not tender yet -- add the beans.

When the pasta is done, the potatoes and beans should be tender. Drain the pasta and vegetables, toss with the pesto and more salt or olive oil if you like, and serve.