Michel Anders is creating a Tree Addon for Blender, that is, in addition to the other tree creating tools that are already available. What sets this one apart is that the Tree Addon uses the space colonization algorithm by Adam Runions, where the model parameters can correspond to visually relevant tree characteristics identified in landscaping, offering convenient control of tree shape and structure.
I wrote a new add-on to create trees that aims to bridge the gap between IvyGen and Sapling in terms of ease of use and results
Michel is attempting to blend and bridge the gap between the IvyGen addon, and the Sapling tools in Blender to create a tree generation tool that provides easy of use and realistic results.
Michel notes that the space colonization algorithm lends its self well in creating realistic trees for architecture in that it is simple to incorporate environmental effects like shadows that are cast by buildings or walls.
Michel has an extensive post showing the details of the Tree Addon for Blender, and its use. The Tree Addon for Blender is available for download and use, and is still in the fairly early stages.