The National Park Service likes to emphasize that it strives to let natural processes play out in the parks, but there are times when rangers must intervene and take an active role in that process. That happened recently in Yellowstone National Park, where rangers killed an elk and bison that were in distress.

Living in the Rocky Mountains is a great asset when it comes to visiting national parks, for there are so many in just about any direction you head. The past year took me north and south through the region to a diverse collection parks, and I also ventured to Virginia to explore the National Park System.

This fall has been a tough one for those who love the wolves of Yellowstone National Park, as more than a few of the predators have been killed outside the park by hunters. Wolf hunting and trapping also is an issue in the Midwest, and the controversy around that issue prompted writer Greg Breining to take a close look at how wolves and science intertwine. It's not always as neat as you might think

While many national park lodges are on the National Register of Historic Places, not all lodges reflect the preservation and well-maintained appearance you might expect for such properties. In a two-part series, the Traveler looks at the highs and lows of upkeep in the National Park System.