In 1939, the search was on to find a suitable karri tree south of Manjimup to be used as a fire lookout tree. This tree, which became known as the Diamond Tree, was pegged in 1940 and a cabin built at the top. It was from this cabin that the tower person scanned the surrounding landscape looking for signs of smoke.

Early detection of bushfires made them much easier to control. Diamond Tree is now permanently closed to climbing after expert assessments found rot in the base of the tree and recommended all climbing should cease.

The Diamond Tree picnic site and walk trail are still open and make an attractive lunch stop. There is information on site about the Diamond Tree and its past role as a fire lookout.