For years it's been hammered into us to dress in layers when we head outdoors for extended periods. But should your base layer be wool or polypropylene when you set off into a national park's backcountry?

Mention wool and many of us have bad memories of an itchy fabric that was incredibly uncomfortable to wear next to our skin. Talk about "poly" layers and we often think about quick-drying fabrics that wick moisture away from our bodies.

Well, wool has all of the beneficial characteristics of poly, and then some. And just as, if not more, importantly, finer wool threads are being used in today's garments than those of yesteryear, threads finer than a human hair, threads that feel almost silky next to your body.

Now, someone in the fabric industry told me earlier this year that if you're just heading out for a quick workout and will be heading back inside afterward, poly is a great base layer. But if you're going on for extended periods, wool should be on your body as it'll keep you warmer while performing the same chores as a comparable poly garment.

Why is that? Well, wool not only wicks moisture, as does poly, but it will keep you warm even if damp or wet. Those in the business say it can absorb 35 percent of its weight in water vapor and will still feel dry. Finer blends (those made with Merino wool threads in the range of 17.5-18.5 microns in diameter go into base layers; outerwear often is made with threads in the neighborhood of 24.5 microns) can be almost silky smooth against your skin, and, unlike poly, wool has a natural antibacterial quality to it to combat your odor after days in the woods.

Plus, it's hypoallergenic and, if you lean too close to your campfire, it's not going to melt like poly. And, in today's enlightened consumerism, wool is not only a long-lasting product, but renewable.

So valued is wool for its properties that you can easily find it in socks, mittens and gloves, base layers, mid-layers and outer layers, mated with Windstopper membranes for jackets, woven into hats, hiking pants, and even cycling shorts and knickers.

Among the companies that make wool base layers (and other layers and garments) are Smartwool, a somewhat new company (dating to the 1990s) that got its start in New England making socks; Ibex Outdoor Clothing, a somewhat older (it dates to the 1970s) company, also from New England, and; Dale of Norway, a venerable Norwegian company that has been making wool clothing since 1879.

Later this fall (possibly as soon as September), Dale will be sending to market its latest base layers. The "180 Baselayers" for men and women (cut specifically for women) will come in both short-sleeve and long-sleeve versions, as well as a partial zip long-sleeve model. Befitting Dale's fashion reputation (Have you seen their ski sweaters? Gorgeous!), the base layers come a bit splashy with a print design that runs down the sleeves.

These 180-gram Merino wool products feel somewhere between cotton and silk next to your skin. During a ski outing last weekend the sample I obtained stayed dry beneath my mid-layer and outer shell jacket. No chills ran through my body after numerous long mogul runs followed by slow rides back up the hill on the lift.

As a bonus, Dale's base layers are machine-washable, so no trips to the sink for hand-washing and rinsing.

These base layers, made from 18.5 micron threads, will retail for $69 in the short-sleeve version, $74 for the long-sleeve crew, and $79 for the zip long-sleeve rendition. Sizes run S-XL for women, S-XXL for men.

True, while shopping for wool layers you might catch your breath at the pricing. The reason, I've been told, is that the companies that make these garments head to much the same Merino wool marketplace as do those high-end suit makers (check the price of an Armani lately?).