Christopher Solomon in a Sunday Review opinion piece for the New York Times. Well done.

When we think of injuring nature, it is easy to point an accusing finger at mining companies and their strip mines or timber barons and their clear-cuts. But could something as mellow as backcountry skiing or a Thoreauvian walk in the woods cause harm, too?

More and more studies over the last 15 years have found that when we visit the great outdoors, we have much more of an effect than we realize. Even seemingly low-impact activities like hiking, cross-country skiing and bird-watching often affect wildlife, from bighorn sheep to wolves, birds, amphibians and tiny invertebrates, and in subtle ways.