One Tree Bridge is located on the Graphite Road just west of Manjimup. The bridge is actually a single karri tree which was felled across the Donnelly River.
Prior to 1904, the only way to cross the Donnelly River was via an extremely hazardous rocky ford. With the opening of the graphite mining venture, an alternative route was necessary for the bullock drawn wagons to cross the river.
The problem was solved when two local axemen located a huge karri tree near the banks of the Donnelly. With a lot of skill and a little luck, they felled the tree to drop across the river to form the basis of a bridge. 
A superstructure was then cut from jarrah trees to form the slabs and decking.
The bridge was now strong enough to support bullock teams and their wagons. During a bush fire in 1933, a burning log fell onto the original bridge, destroying the jarrah decking. Rather than remove the log and rebuild the bridge, jarrah planks were placed lengthwise on the log, creating a new bridge. Curbs and rails were also added as a safety precaution.
Not surprisingly ten years later the bridge was declared too dangerous for public use, even though there was no alternative crossing.
A second bridge was opened in 1948, leaving the old log bridge to fall into disrepair. During a particularly wet and windy winter in 1964, the One Tree Bridge fell into the river and remained there until 1971 when a section of the bridge was pulled out of the river by the Glenoran Forests Department and rebuilt.
Just near the bridge is the area is known as Four Aces where 300-year-old karri trees line up in a single file. The average height of these enormous trees are over 72m.
