August 1921
O. C. Simonds & Co.
circa 1958
Tyznik, Anthony
1982
Coulter, Ronald M.
1984
Hart, Nancy
1990
The Morton Arboretum
July 1 1983
Ralph F. Gross & Son Associates, Inc.
August 28 1984
Forest Preserve District of DuPage County
June 17 1986
Forest Preserve District of DuPage County
circa 1958
Tyznik, Anthony
circa 1958
Tyznik, Anthony
February 26 1996
Mehaffey, Scott A.
January 22 2003
Christopher B. Burke, Engineering West, Ltd.
May 23 2002
Christopher B. Burke, Engineering West, Ltd.
2005 – 2012
Hagstrom, John