Building a Gingerbread tree is part skill, part luck, and part "globbing-it-on".
There are probably many different methods in which to build a Gingerbread Tree, but below is the method that I use. (Sorry there are no pictures.... I will get some loaded as soon as I am able to build another tree and take pix.)
Measure your oven and make sure to build your gingerbread tree small enough to fit inside your oven.
Cut a 6" square piece of 1/4" plywood (or whatever size you want).
Drill small holes in the plywood, where you will secure your wire-frame tree.
Using a couple of wire coat-hangers, bend them into the shape of a tree trunk and a few main-large branches, leaving wire coat-hanger ends to be set into the plywood-drilled holes.
Set the wire-coat hanger tree form into the plywood-wood drilled holes and secure.
Cover the wire coat-hanger trunk and main-large branches with very crinkled aluminum foil (so the dough will fill into the crinkles and stay attached (not drip off)).
If desired, with aluminum foil make smaller branches and attach to the tree trunk/larger branches.
Roll out your gingerbread dough and cut into strips and triangles to cover the roots of the tree.
Using pieces of gingerbread dough, wrap tree trunk and branches, pressing the dough into the crevices and crinkles of the aluminum foil.
Be careful to not make the dough too thick as the dough may droop during baking.
Wrap tree trunk and branches with brown thread. The dough expands when baked and takes on a gnarled look. This also helps to keep the dough secure to the wire tree form while baking.
If desired, press flax seeds into the dough for a different kind of look.
Bake gingerbread tree in preheated 300 degree oven until it starts to brown on branch tips.
Let cool before handling.
Secure wood base (with gingerbread tree) to your main gingerbread house base.
To make a tree-fort, cut gingerbread pieces for floor, walls and ceiling, or use crackers to build your tree-fort. Tree-forts usually only need a floor and roof pieces.
Assemble your tree-fort on top of your tree, let set, and decorate.