September 1956 (age 57)

The first part of the month was taken up with Sigurd's first meeting as a board member of the Wilderness Society. The meeting was at Rainy Lake, home of board member and Olson mentor Ernest Oberholtzer. So, Sigurd and Elizabeth took council member George and Jim Marshall, and Bernard Frank and his wife, Miriam, on a weeklong canoe trip in Sigurd's favorite portion of the canoe country: the Quetico Park chain of lakes Robinson, Sarah and McIntyre. After the annual board meeting, Harvey Broome wrote to Sigurd, saying:

We had some inkling of the maturity of your judgment when you sat with us at the Montana meetings three years ago. It was grand to have you again this year with the same maturity of judgment and with a voting voice as a member of the Council. If we continue to replace retiring Council members with the strength which was added this year, I have no fears for the future of the Society.

September 1971 (age 72)

Because his health isn't what it was before his November 1968 heart attack, Sigurd resigns as Wilderness Society president during the group's annual board meeting, held this year at Isle Royale National Park. He accepts a three-year term on the board and executive committee. George Marshall, who will become the new president, praises Sigurd, saying:

We have had a line of distinguished presidents: Robert Sterling Yard, Benton [MacKaye], Olaus [Murie], and Harvey [Broome], but none of them raised the level of our thinking and work as you have. As a wilderness philosopher, writer, and traveler, as a stimulator and encourager of staff and council, as one who has broadened our outlook you have done so very much for the Society and conservation movement that listing does not begin to express what I should like to say. In addition, you are one of the few of our group who has that rare capacity that Jim has called "the ability to get things done," the ability to persuade those who make public decisions among administrators and legislators and many others as well.