Moss seems to be ok, even submerged, but then you have to use java moss which is aquatic, not terrestrial from the woods.
Well I'm not sure about bleach, i know some people do it, but i am 99% sure that just hot water will do the job. I mean, water from home boiler is usually hot enough to kill most of the bacteria, and if you are careful about where are you taking it from, you won't have any problems. When you collect it make sure that its dry.
Pines have resin, and its bad for water. I remember seeing some breathtaking pines by Colorado river in Utah. They were huge and so dramatic that I could totally imagine one big piece in my tank, and it looked amazing. To bad It can't be used, otherwise I'd carry one 10.000 miles back home
Oak is ok, but your water will turn black. It would be brandy colored after few days because of tannin oak contains. But its ok, no harm to the aquatic animals.
And thanks, guess it almost my native language, I've been speaking it since I was 3