What wood to use for tank?

[Grizzly]

So I’m thinking about rescaping my 75 gallon tank and was thinking about finding a piece of wood that would fit the length of the tank. My question is what type of wood can I use?  I’m assuming a hardwood over softwood  but what about wood I already find in a lake or River? Is there anything that needs to be done before adding to my tank so the fish don’t die from it? 

[Val]

Avoid coniferous woods and green wood.  Boil the heck out of it.  And I'd let it soak for a week in a hydrogen peroxide solution.

[JettsPapa]

If you can find a piece of hardwood that's completely dry, so dry that all the bark has fallen off, there should be very little danger if you rinse it with a hose and drop it in your tank.  That's what I do.

[rockfisher]

Agree no pines or any other sappyfffff wood. You can dry wood next to a fire. Large pieces are hard to boil.