Aesthetically rock can be a better fit for steps, benches, technical trail features and it certainly is much more permanent than wood.
Using a wood structure is one method of dealing with unique trail issues, but we feel in many cases rock is a better solution. It comes naturally to our staff to work with rock. Both principals of the company are bricklayer/stone masons.
In more urban settings, discarded concrete debris and recycled concrete granular provide a good base material for trail construction, lowering the project costs while keeping these materials out of landfill. If required for aesthetics, natural rock can be installed over this base concrete.
Armoring high traffic areas and water crossing with this recycled materials or rock literally provides a permanent trail tread.