after many decades of logging, efforts were started in conservation. in the 1920s the save the redwoods league worked to save old-growth redwoods. due to their efforts, a number of state parks were formed. then in 1968, redwood national park was created. by that time nearly 90% of the original redwood trees had been logged. the national park service (nps) and the california department of parks and recreation (cdpr) combined the management of redwood national park with the three redwood state parks in 1994.