If you are going to put the work in building a forum about Apple products I would not use this domain name, that would be a violation of their TM and you would be putting yourself at risk for a lawsuit. At the minimum you could lose the domain name.
It would be a much smarter move to purchase a diferent domain name that is not in violation of the Apple trademark. You can talk about Apple products all day on your forum, just don't use the TM "Apple" in the domain name.