Good SGR article from the two who brought it to our attention

[Tom Dunlap]

Dr. Gary Johnson was the person who got our attention focused on SGR's when he observed some trees on the U of Minnesota campus that didn't look right. His first work was with a pressure washer and shop vac. Look what he started! Dr Rich Hauer joined Gary and the rest is history!

Here's an article that they have written.

http://www.mnstac.org/uploads/2/0/9/3/20933948/relationship_of_structural_root_depth_on_the_formation_of_stem_encircling_roots_and_stem_girdling_roots.pdf