Best bet is to put it near one of the other dead trees and hope that it finds a suitable place to hibernate. Once you put the bat against the tree (at the base of the tree), you may need to GENTLY prod the bat with a broom handle (i.e., something other than your hand, which could accidentally get bitten) to get it to rouse enough to be able to move. Once it starts to seem alert, back away and let it do its thing. They have very little fat. To survive the winter, it will need to move as little as possible so as to not waste precious energy. Good luck!!