This post comes a bit late, but since quite a while elm-logo has all the features reqired to draw a fractal tree using this algorithm from Rosetta Code (only pendown was added).

to tree :depth :length :scale :angle
  if :depth=0 [stop]
  setpensize round :depth/2
  forward :length
  right :angle
  tree :depth-1 :length*:scale :scale :angle
  left 2*:angle
  tree :depth-1 :length*:scale :scale :angle
  right :angle
  back :length
end

clearscreen
pendown
tree 10 80 0.7 30

Open snippet in elm-logo (in elm-logo, click “Run” to run it)