While there exist many models that show tree root growth over time and space, few have a data-driven spatial engine. Using the ArcGIS framework I have developed code for constructing tree root and branch systems and visualizing them in 3D.
I have a whole root branch in now. Annual rings comming soon! Note: Some of the roots do not draw at all angles using Cosmo. They are there but do not draw for some reason or another. They work fine in the GIS however.
Here is two years (81 and 82). 82 is transparent so you can still see 1981.