Looks to be pressure treated lumber which really requires nothing applied to it. You could paint the wood if you wanted but any other sealants won't do anything to help really. Pressure treated wood normally has a 20 year ground contact warranty (if the receipts and tags are all available).

Looks pretty good and not as old as the home. Keep the water out of the wells and let them dry out are the best things you can do.

Thanks, millworkman and Windows. I normally keep them covered with custom-made polycarbonate covers.

That will help.

There are many coatings available for pressure treated wood . I prefer oil based products. There main purpose is to keep the wood from taking in water which the covers are doing and most likely why it still looks good.