I have made those 3D trees about a decade ago. Those were my first 3D models of plants created using L-System code for Vue. They are not super quality, but I was learning then. (never used L-System before).
I am happy you like those models, but beware that e-on may still hold copyrights for those 3D plants.
By the way, you can visit my new website about 3D vegetation - a hub of knowledge about issue linked to creation of 3D tree, 3D palms, 3D flowers and other 3D vegetation :