April 1949 (age 50)

Sigurd spent the beginning of the month (and his 50th birthday) in Toronto, where he finished his work organizing a Canadian Quetico-Superior Council to generate public support for the canoe country north of the border. He also made arrangements to introduce a Canadian version of his documentary film, Wilderness Canoe Country, designed to build support for a ban on airplanes in the wilderness. Cinema Canada distributed the film, and it was soon in steady circulation.

The American version of the film was still getting a lot of play, and was continuing to bring in supporters. The director of Minnesota's Bureau of Information said his agency's copy was booked three months in advance, and he had "never witnessed a more enthusiastic reception of an outdoor film." With Sigurd's permission, Detroit TV station WXYZ aired Wilderness Canoe Country, and viewers began writing to Sigurd for information on how they could help the conservationists ban planes from the wilderness. Because of the film, by the end of April 75 organizations in northeastern Minnesota had gone on record in favor of the airspace reservation.

April 1964 (age 65)

In mid-April Sigurd joined other members of the National Park Service's advisory board for its spring meeting in Washington. At the meeting, Park Service Director George Hartzog wavered on the proposal to create Voyageur National Park in northern Minnesota. Fearing that Congress might not approve the park, he thought the board should consider proposing a lesser designation, such as a National Historic Waterway. Sigurd, who had been a strong supporter of the proposal from the beginning (and had even suggested the label "Voyageur"), said to change its designation once the proposal was underway would make its chances with Congress considerably worse. The board agreed with Olson, and affirmed its stance in favor of national park status.

Park Service officials also reported at the meeting on efforts to restore water flow to the Everglades, a "dying park." Sigurd reacted strongly to the presentation, as shown by the following quote from the board's minutes. The advisory board supported Sigurd's recommendation.

In the discussion that followed, Mr. Olson said he thought the Secretary [of the Interior] should sit down with the Secretary of Defense and tell him the Park values will be lost unless he issues an order to the Corps of Engineers to revamp their program and find some way to get sufficient water to come down into the area.... Mr. Olson said he thought this was a drastic emergency; that there was only one solution and that was to go beyond the Corps. He recommended that the Service go to the Secretary of the Interior [Stewart Udall] and explain the situation. "He knows what a park means as far as getting one is concerned," Mr. Olson declared, "but here we are faced with having one literally taken away from us." He recalled that over the years the program of the Army Engineers has resulted in a diversion of fresh flowing water from the Everglades into community developments, as well as into the sea. The Army, he said, could take care of the situation by diverting water back into the Everglades, particularly from the outlets that drain the water into the ocean; that dikes and dams within the Everglades are not good, but would only destroy or mar the Everglades and not recreate the natural ecological environment. The time is past for surveys, he concluded. There is one solution, which is to divert some of that water back into the Everglades. If that is not done the Park will be destroyed.