The simplest way to resolve this is through git-archive. For expanding tree you can go with
$ git archive master | tar -x -C /somewhere/else
If you need to export from git you need an archive, for that use
$ git archive master | bzip2 >source-tree.tar.bz2
For archiving ZIP:
$ git archive --format zip --output /full/path/to/zipfile.zip master
If you are interested in exporting index, the command is
$ git checkout-index -a -f --prefix=/destination/path/