Join Date: Jan 2012
Location: San Antonio, TX
(My two cents/not any kind of expert)
I think that it will be perfectly fine but that it will almost definitely affect the pH. I think that so long as you keep up with water changes than that effect will be minimal and if anything the fish will like it.
I base this on my personal experience with putting wood into tanks; I have defied all the conventional advice in this regards. I have put huge, essentially planks of maple from my yard into a tank, with bark still on. It darkens the water up, but A 40% WC a week keeps that in check. Fish like to pick at it. Shrimp and snails love it. The wood was almost certainly still green in places. I soaked it for a long time just to keep it from floating, but that is all, no boiling or other sterilizing.
I think that in general concerns about wood are overblown and that the main things to worry about are pesticides, which, it being from Pacific and assuming you rinse or soak it a bit are mitigated, and the wood itself having some harmful chemical properties. I'm no botanist, but that seems like a far outside chance so long as you aren't putting sappy pine branches in.
In either case, if the wood is pre soaked ahead of time so that it sinks (something else I have skipped before with no resultant problems) than by the time it will stay down you're golden.