I've never heard of it either, but as long as it is not pressure treated, or uses any metal based preservatives, you should be ok. Most folks here prefer high quality, non-PT, exterior grade plywood sealed with either polyester resin and fiberglass mat, 2-part epoxy, or the Spar Urethane mentioned. All hardware should be either aluminum rivets and/or stainless steel hardware dipped in 5200 marine caulk. That's really about it. The rest is up to you.