The circuit walk through Ferntree Gully Reserve passes through a scenic gully containing interesting rainforest vegetation. This includes various types of ferns as the name suggests, as well as vines and trailing roots reaching down over rocks to find the ground below. There are also good views from above the gully. It’s a short but rewarding walk that I recommend if you are in the region around Rylstone.
There’s information on the Visit NSW website, but there’s a simple map of the walk at the trail head, and it’s pretty straighforward to follow the track. We did the circuit including the short boardwalk side trip and the two lookouts (leaving out the Wheelbarrow Track, which is just for people with garden equipment). If you want another good walk to do in the area then drive over to Dunns Swamp and do the Pagoda Lookout Track.