I see a lot of aquariums with branches in the tank.
Are people buying these branches some place or are they getting them from outside and sticking them in the tank?

You can buy them or pick them up if you don't feel like paying for wood. Either way you'll have to soak them for a few days to release all the tannins that will color your water. Also if you pick them up you have to make sure they're completely dried out. If you live around an area with lots of trees you may be able to find very unique pieces that you could never get if you ordered or bought.

You can find wood outside and use it. It helps to boil it before you put it in your tank to kill anything that might be in it (fungus or bacteria). You would also need to either tie it down or soak it for a long time to get the wood to sink in the tank. You also want to use a hardwood so it wouldn't deteriorate and produce as much tannins as a softwood.

I've used wood that i have pullled from a stream before so that it would sink and it didn't cause any problems in my tank

I am going to agree with BombDame. I did some research on it and I don't think it is wise to be
picking up sticks in the woods.
Not to BombDame. = I got your message on the Tiger salamanders.....
I have had them for a few years. They are crazy escape artists.

I get my tree branches from the side of the sidewalk when I'm walking back from class (I'm a college student). Dead branches fall down after windstorms and are quite pretty sometimes. You want to get wood that is thoroughly, completely dead. And don't use wood from every tree species. Some of the trees (walnut trees, some evergreens) have poisons in them. In general, if the tree is one of the species where no part of it is poisonous, then it's safe to use in the fish tank. Just google the tree before you use its branch. If it has no poison warnings, it should be fine.
I wash them with bleach and thoroughly rinse them. You can't really boil the longer branches because they're simply too large to fit in a stovetop pot.

The wood sinks after about a day in water. I prop it in the first day, but after that it will stay submerged on its own. Wood grows mold after about a half a year or a year or so, so you want to keep an eye on it and watch for dots on the surface. Remove it when you see stuff growing on it and get a new branch.

If your water starts to turn yellow after adding wood, put fresh activated carbon in the filter. I buy my activated carbon in bulk and then fill filter bags with it by hand and it costs about a sixth of the price. The fish don't mind the tannins (yellow stuff) that leeches out of the wood, but I like my water crystal clear, so I filter with activated carbon. Actually, some fish (tetras, bettas) are more likely to breed if there are tannins in the water, I should mention.

Good luck with your wood. It's very pretty, I think.

Pictures of my aquarium:
http://img.photobucket.com/albums/v415/Okiimiru/069.jpg
http://img.photobucket.com/albums/v415/ ... /058-1.jpg

The majority of wood in my tanks is wood i have found. I just ensure it has fully dried out and is hardwood (majority is gum tree). I have 15 tanks and buying wood for them would be far too expensive.

I dont take from rivers at all or from where crops are grown. I take from near livestock paddocks. I have been using it for many years with no ill effects

This was one set up...shows the wood layout...and the other pic shows it planted