I found the on thatartistwoman.blogspot.com/. It's a Christmas craft she did last year - here's the link: http://thatartistwoman.blogspot.com/2008/11/how-to-make-mini-christmas-trees.html. Plus it was posted on One Pretty Thing (http://www.oneprettything.com/?s=christmas%20tree&st=c&s_paged=3) - a favorite blog that pulls craft ideas from all over the web!
(for more specific details check out That Artist Woman's blog)
Just cut felt into 10 circles - 2 of each size. Cut holes in the center and slide them over a toilet paper tube (cut the top of the tube to a V shape). Then decorate - pom poms stick ok with glue and we also used sticky gems and other decorations. Add a gold star to the top. Then take a wooden base (Michaels sells them for $1), cover with felt then hot glue the bottom of the tube to the base. Hot glue the top on the tube to keep it on as well. Add package ornaments under the tree and voila!
Some of the trees made by the other Brownies: