You're not generally allowed to destroy other people's property just because they're trespassing with it. They may have committed a crime by trespassing, but that's a matter for the police and the courts.
This is of particular personal interest to me, because I fly gliders and sometimes we end up making emergency landings on other people's property when the weather doesn't quite cooperate with us.
My understanding of the law there is that I'm liable (and covered by my insurance) for any damage I cause to their property in the course of landing and retrieval, but the property owner can't stop me from retrieving my aircraft, and can't intentionally damage it.
Now, the fact that it's technically an emergency landing does change things a bit, for example my actions aren't a crime the way normal trespass would be. But I don't believe it changes the property owner's rights and responsibilities.