In 1905, at the instigation of the Cook County Board of Commissioners and private nature groups partly guided by prominent landscape architect Jens Jensen, Illinois adopted a forest preserve act. However defects in the law caused it to be declared inoperable. The Forest Preserve District Association was formed in 1911 and a new state law was adopted, however, the courts declared the 1911 law unconstitutional. Finally in 1913, the State adopted a Forest Preserve Act that survived legal challenge. The 1913 law allowed a county board: