Knowing the material of the clothes you're wearing is fairly easy, but being able to trace that material to its source, well, that's something. Particularly when you're wondering where the wool in your shirt came from.

Most folks who backpack or hike are looking for, or have made, a connection with the landscape. You can enhance that connection with garments from Icebreaker, a New Zealand-based company whose forte is making clothing from fine merino wool. Stitched into their products is a tag that carries a "Baacode" number that, when input into Icebreaker's website, traces the wool in your garment back to the sheep station, or stations, from which it came.

In my case, the "ingredients" for my GT 200 long-sleeved technical base layer (the LS Sprint Crewe, MSRP $100) hailed from three stations: The Glenmore Station, Muller Station, and the Otematata Station.

All are located on New Zealand's South Island, a rugged landscape of valleys and mountains where the sheep roam pretty much at will until it comes time for shearing. All are family operations, some tending sheep on land that's been in the family for a century. You'll find a little bio on the families, a map of where they're located, some details on their sheep, and even some family photos.

Can you learn that sort of detail from your cotton T-shirt or fleece mid-layer?

When I headed off into the Bechler region of Yellowstone National Park back in September, among the items in my pack was the Sprint Crewe and a GT 200 series pair of their Sprint boxers (MSRP $55). For comparison's sake, I also brought along a merino base layer from Dale of Norway. I figured I'd wear one during the day, and change into the other at night.

The results: Once you go to wool, you'll never go back.

Well, perhaps you will. But wool has some great things going for it: Not only does it wick moisture, as does poly, but it will keep you warm even if damp or wet. 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.

The GT series comes into two weights -- a 200 lightweight for aerobic sports, such as running, cycling, or training, and a 260 midweight for high aerobic winter sports, such as skiing or snowboarding. Of course, either can also be used for hiking or backpacking.

I found the long-sleeve to be extremely comfortable. It molds well to your body, is silky smooth and, perhaps best of all, durable. While the Dale also is comfortable and warm, I found it a bit more delicate; if I'm not careful when I slip it on, I can hear some threads snapping around the neck and shoulder seams.

The Icebreaker, perhaps due to a slightly larger opening for your head, so far has held up much better. Part of the reason might be the construction: Icebreaker integrates two thicknesses of merino yarns and tosses in 3 percent LYCRA for stretch.

I'm not sure, though, that the wool boxers are the way to go in the backcountry. Synthetic underwear seems to retain its elasticity much better if you like a secure fit. However, once you toss the Sprint boxers into the wash they retain their original fit.

As with the Dale baselayer, the Icebreaker garments can be tossed into the washing machine.

At the end of the day, wool garments might be higher priced than some synthetic garments. But when you consider how they wear, and their place in a sustainable world, they're worth your consideration.