Have fun fixing up those trails man! If they are fairly new and have been trashed already id find another spot to build stunts though. If they get wrecked once they will again. If they are old and falling apart or just not well built then go nuts! If you can find the person who started the trails & talk to them they might be able to give you more insight as to what went wrong. One season with no maintenance can wreak havoc on trails & make them look horrible. Also one idiot in an afternoon can wreak havoc.