If you are looking for sustainable roof sheathing materials, you are in luck. While this was not always the case, today options are available that can get the job done without draining the planet of natural resources. The following roof sheathing options may prove useful to you.
Recycled roof sheathing materials require no use of new resources, making a great sustainable roof sheathing alternative. One such option is medium density fiberboard, which is often abbreviated as MDF. Oriented strand board, or OSB, is another, similar option. Both of these materials are similar to wood in many ways, and are easy to substitute in its place for many things such as roof sheathing.
You might also investigate some less obvious recycled materials, as it is possible to use straw, waste paper, peanut shells, and other often discarded materials in combination with chemical additives for the purpose of roof sheathing.
While wood should be last on your list, there are many manufacturers who make a point of using wood in a sustainable way. Because of this, if you are committed to using wood, you still may have sustainable options.