How do you create gnarled tree shapes like this in GIMP and other graphics programs? ?

Question

(I can't afford Photoshop)

http://img401.imageshack.us/img401/4076/gnarledtreeshapesaa8.gif

Answer 1

they probly either freehand it with the pen tool or use paintbrushes to create it ....  I know with photoshop and corel you can download paint brushes ... like one paint brush might be a branch that points towards the right and another brush might be a branch that points left ..... I have no clue if GIMP has brushes you can download though .... and btw I cant afford photoshop either, but I have it ..... and Corel PSP X2 as well  ;)