Question
We have had some root damage a few months ago (I would estimate 4-5 clock hours) to a ~120 ft tall Douglas Fir during a driveway installation. Is there a time frame where we could expect to have some visible damage to it if it has occurred. ( there does not appear to have been any change to the tree that I can see)
Is it reasonable to say that if there does not seen to be any visible change to the tree in 3-4 years it will be ok if is this a permanent risk??

We would prefer to leave it since it provides the majority of shade from the sun but ( we live in WA. state) often see wind storms bring down trees and since it is about 10 ft from our house don't want to take any unnecessary risks.

I understand that there are a lot of variables that can effect this ( I assume like soil) but would help any guidance you can offer

Thank you
 BILL

Answer
The damage should show up the first growing season and maybe the spring following the damage. After that the tree will adapt to the loss of roots. The amount of damage will depend on how close the digging was to the trunk and the amount of roots damaged. If the damage was more than 30% of the root system you can expect about that much foliage die back. To calculate the percent draw a line around the tree where the branches extent to and then draw a line through this circle where the digging was located and if the piece that was cut from the circle exceeds 30 % then expect die back from the damage. You are right soil comes into play and the amount of rain fall also. Hope this helps.