I use XFrog to Create the Trunk of the Alien Tree. Using a Flower Spline that sweep along the Helix spline. The Flower at the end of the trunk is just a simple Cone that has been tweeked then Hypernurb and a sphere for the center of the flower.

I Copy the XFrog Branch object and use it as a second Sub Branch of the original XFrog Branch object. This make a tree with a Trunk and One level of Branch and No sub branch at this point.

I create the Leaf by using the XFrog Branch object and Added the Flower as subbranch and End of branch.
In the Final I decided that There was to many flower and remove the Flower that was used as Branch from this stage

I added the Leaf I created in the Last step as a Subbranch of the 2nd level branch and this is the Alien Tree I end up with.

I convert the Alien tree that was created in the last step from XFrog Object to a polygon object. I then place a few copy if the tree in to the scene changing the scale and Rotation of each one. I added a few Landscape object and moved them around so that they cover the floor of the scene. I then Added 2 omni light one is yellow the other Blue. Both omni light was set as Volumetric Light. I placed a Target Camera into the Scene adjust Camera for a Good View. Do a few test render at low resolution before deciding on the right View and do a Final Render