Here is a great run down of wood types by a master carpenter, Stan Pike. Check out that page. It is cool.
I found the site while researching Black Locust, an underused wood in the US. It is considered a weed pretty much so grows in abundance. It is one of the hardest woods around and has really amazing rot resistance.
In terms of green lumber I think it is the best after salvaged. As green contractors in Brooklyn we have been looking for green decking options for back yards and roof decks. The salvaged wood is mostly fir and although we’ve used it we also know it does not have a long life.
There is recycled plastic decking (without wood chips) that lasts a really long time. We have used it and sure enough the decking lasts and lasts without any maintenance at all. But it gives off a slight plastic smell. Nothing anyone would really notice but if your job is to be on the lookout for possible toxic off gassing like we are then it does give us second thoughts to use it again.
This is why we are happy to learn about black locust. We found a supplier. So our next deck job will be with black locust.