How do I set up collision detection for trees?

I am new to this and am still RTFM so please be a little patient with me :frowning:
I am just trying to figure out how to have collision detection on a tree, so that when I mass place them, the character does not go through them.
I also want to do the same thing with the floor of the terrain.
Any help is appreciated.
I am reading the flipping manila as this is posted.

Thanks everybody!!!

in project tab make a new prefab called โ€œtreeโ€ then drag a tree model you want to use onto that prefab. Now any scripts / properties you put onto that prefab will apply the same script / properties to all the trees that are made from that prefab.

Also to get collision working I have to assume you know the basics of coding and how to apply a rigidbody to the character. If you dont know how to do this then you should do some youtube tutorials they are really handy.

I just had a quick look and this one seems to do what your after