I wonder if you could settle a question for me? A number of years ago we took a vacation to Canada. We went to Waterton Lakes National Park, which is the Canadian section of Waterton Lakes/Glacier International Peace Park. We also went to Lake Louise and Lake Banff.

At one of the lakes, I don't remember which one, we took a boat trip. At one point we noticed that a wide swath of trees had been completely cleared from the top of the mountains down to the water and the same from the other side of the water to the top of the mountains.It was a completely denuded strip that looked about 20 feet wide. They told us it marked the boundary between the U.S. and Canada. My family tells me it is impossible to have a boundary there. Will you please set us straight on this? - D.M., Salt Lake City.

The clear-cut strip does indeed mark the U.S.-Canadian border. According to a naturalist at Waterton Lakes National Park, the U.S.-Canadian border, which is under the jurisdiction of an International Boundary Commission, is marked from coast to coast. The border pretty much follows the 49th parallel from the west coast until it reaches the Great Lakes. In areas where there are trees, the border is marked by a swath like you describe. In the plains provinces the border is marked by stone or concrete markers.

The border was originally marked in the 1800s. In the early 1970s, the swath through the trees in Waterton Lakes/Glacier National Parks was maintained by spraying it with a herbicide. Park authorities protested and the border was cut manually the last time it was maintained, which was about three years ago.

"We would prefer the border not be marked. We'd prefer to let it grow in," said the naturalist.

He said the International Border Commission considers the clear-cut border necessary for border patrols to work effectively and for the enforcement of customs regulations.

As far as Lake Louise and Lake Banff are concerned, if you had looked at a map you would have realized that Lake Louise is too far north to be a consideration in your question. And there is no Lake Banff.