Answer: You have asked an interesting question. Unfortunately in a brief search I am not able to confirm your story. Pinus attenuata x Pinus radiata will hybridize naturally as indicated at the reference below, and you may find it and its reference list interesting. You may need to cut and paste the complete url to make it work correctly.
Unfortunately I am not familiar with Coos Bay area to tell you if this could have happened there, or if they were introduced as you have been told. You might check with your local forestry department and county extension to see if they can help you verify the information about Mr. Simpson and his work in the area.
There is a champion Monterey Pine near Coos Bay, so I would suspect he may not have been the first.
I'm sorry I don't have a more specific answer for you but I hope this helps you with your research.
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