It's easy to assume that natural wood is the best and greenest choice for a countertop. But, as with the other products, you want to investigate.
Ideally, you should use salvaged or reclaimed wood. This cuts down on the need to harvest new product. If you can't use reclaimed wood, the best choice is untreated wood from sustainable, local forests, which minimizes the costs and energy needed for transportation.
Of course, the wood isn't the only thing to consider. If you use a sealer or cleaner on the wood, go with a low-VOC emission product. Additionally, wood countertops may have a laminate on top, and often, these laminates contain formaldehyde. Look for a laminate with a minimal amount of formaldehyde, or even better, one that is formaldehyde-free.
Once all of that has passed your inspection, you'll have a great-looking countertop that has a high green standard. And, the good news is that when you're ready to remodel again, your wood countertop can be recycled.