usually to get the concave/camber with wood it is done with steaming and glue up on a jig and will also depend on the cut of the wood...face vs qtr sawn. Most decks are a glue up epoxy lam that is probably done with a press/jig or a vacume clamp/jig.
ahhh...did you notice this ^ ...not shaping with planer or table saw
I did notice this, and i know about those processes but the fact that i'm using scrap solid hardwood means that i can't use those methods or don't have the right equipment. When i do get the time to purchase some baltic burch or maple veneer i will do one of the proper methods for giving concave or camber, but for now i will use what i got.