How to make blocks collide - help fast please

So i have just finished my Terrain making and my map looks awesome, if i should rate it:P
But my problem is my “player” which is an First Person Controller, when i press play and run around with it it can run through the trees and fenches which i have placed, it can basicly run through everything except the mountains and the ground.

Please help me to add some collide stuff to all my blocks, even if it requries me to do it one by one with the blocks, thanks!

For Trees checkout the Tree Collision portion of this doc.

Trenches and such you will need to add a Collider of some sort; probably Box, or Cylinder will match best.

Unfortunately there isn’t a quick solution without knowing how your scene and terrain are setup.