For the first 50 years of forestry in Western Australia an early warning system for bush fires depended on a network of lookout towers. These towers were built about 40 km apart on prominent hills in the forest, and were staffed continuously in summer. But the karri forest posed a special problem. With few peaks, and giant trees towering 70-80 meters above the ground, the task of building a tower to overlook the forest was formidable. Then, in 1937, young forester Don Steward (who later became Conservator of Forests) suggested using the trees themselves as lookout towers.The first tower was built on a large marri tree at Alco near Nannup. Eventually 13 towers, some of them built in trees, watched over the karri  forest.

Today only the Gloucester, the Diamond and the Bicentennial tree towers remain. The modern 'towerman' is a pilot flying high overhead, watching for smoke and reporting details of any forest fires.

Four trails leave directly from the Gloucester Tree site. The Dukes was is an easy 400 meter meander through the karri forest around the base of the enormous fire lookout. The Karri Views 800 meter trail leads to the edge of the valley, carved by the bubbling Eastbrook below. The Gloucester route is a challenging hike of 10 km with quite steep and difficult sections. The fourth trail is the Town Walk an easy 3 kms into the township of Pemberton.

Part of this forest was logged in the early 1940's. There are areas where smaller, vigorous, closely spaced karri trees grow among the larger forest giants.