Taken from [[https://www.portland.gov/ppd/trees-development/construction-and-tree-preservation/prescriptive-path|Portland tree code]]

Roots over 4 inches in diameter should not be cut.

root encroachment zone is one foot for every inch of diameter. 

See [[https://www.portland.gov/ppd/documents/tree-code-information-guide-calculating-encroachment-prescriptive-tree-protection/download|this]] handy pamphlet.


What is the diameter of the oak tree?  
Circumference is ~83". Therefore, Radius is 13.2", Diameter is 26.4". 
New measurement: C 84.5", D 27.05", R is 13.53". 



Aha! It's measured from the CENTER of the trunk, which saves us a bit. yay! 

So, we MUST be ~149" away from the tree.