the amount of actual wood in the tank is minor. 5 dowels, each about a foot long. i doubt the wood itself will create much nitrate, but it's possible the wood could absorb things that should be filtered out. however, this tank has a decent sized fuge on it, and a good amount of live rock. it should take care of that issue.
as far as the rotting, we're not sure. it will last plenty long to find a worthy replacement. and it's also a possibility that the rock will be fused together by growth- coralline, coral overgrowth..things like that very well could sure those rocks. but it's all a learning process. shavo and i decided to try something new instead of following everyone else.