...he says we will get lightening strikes as we are so high up, ...
The Old Man is right, LG. Lightning is a serious problem for any antenna and you are well advised to do everything possible to protect against the strikes that, without a doubt, will happen. I would strongly suggest you avoid using any tree as an element of your antenna or its support system.
Think about what you've been told to do if you happen to get caught in a thunder storm. I know I was told to NEVER take shelter under a tree. It is incredibly sound advice.
You should put every bit as much research and effort into lightning protection (more, actually) as you would, I'm sure, put into the antenna itself, assuming your dad ever allows it.