The 51m high Diamond tree lookout is located approximately 10km south of Manjimup on the South Western Highway. This massive Karri tree has been operating as a fire lookout for over 65 years.
Constructed in 1940, the tree still remains in active service as not only a fire lookout but also a tourist attraction. If you aren’t scared of heights, trees or, really tall things you can attempt to climb the sucker. But be warned it isn’t for the faint-hearted, in fact, it is downright frightening, all you have are metal spikes (which have been hammered into the side of the tree) to climb up. If you wonder, like me, how safe the climbing pegs are, I have been informed they were replaced in 1991.
Climbing Diamond Tree Lookout
Yes, I have attempted to climb it. Reluctantly I began my ascent checking the strength of each peg as I went. I managed to climb halfway up before being scared off by a huge warning sign at the resting platform. 
Evidently the first part of the climb is the easiest, the second half is a near-vertical climb that narrows considerably.
As is always the case, it is only at the halfway point (when your halfway up the tree) you are advised not to wear a backpack. So if you aren’t scared off by big warning signs or wearing a backpack, you will find at the top of the tree a 2.5m x 2.5m wooden treetop platform.
The tower is the only treetop tower in the world. When the Diamond tree was opened to the public in the 1970s it attracted over 2,000 people per year.
Remember you climb at your own risk but children are not permitted to climb the tree (ever!) as the rungs are quite a distance apart and it’s very, very dangerous. You are also warned not to climb during wet or windy conditions, but I would guess that is a given. I must say it is probably one of the few remaining terrifying experiences still open to the public in Western Australia.
Whoops, I spoke too soon, in 2019, the lookout was closed to the public. I guess health and safety got wind of it!
Treetop Lookouts
The treetop lookouts were built during the late 1930s as a way of identifying the location of fires which often flared up amongst the tall timbers. Today light aircraft take on the role of fire spotting and the Department of Conservation and land Management (CALM) are actively involved in preventative measures in reducing the intensity of wildfires.