Carefully separate the branches of the desirable tree (assuming the needly thingy ) and take the unwanted leafy thingy out in pieces. You can probably take a good portion of the leafy thingy out with pruning loppers, the larger trunk sections can be taken out with a chainsaw, sawzall, bow saw, or hand saw, whatever you have at your disposal. If you've got a fireplace and can burn wood, buck up the discarded tree into usable pieces and store it for 6 months to a year before burning (to cure/dry it, it will burn better/cleaner ).
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!