Recently a drunk driver took out a douglas fir in our yard. He hit the tree so hard it literally sheared it off and there are only a few roots sticking out of the ground. The tree was approximately 8"-10" and 20' in height. This tree was in our side yard and provided a beautiful barrier to the nearby highway. The driver's insurance company is offering only $100 to replace the tree. I have contacted many nurseries in the area (Willamette Valley, Oregon), but no one sells trees that big; therefore, I need to know how to estimate the value of the tree.
Thanks for your help.

I recently conducted a two day tree appraisal seminar for the PNW Chapter of ISA. There are a number of well qualified tree appraisers in Oregon. There is probably a link from this site to PNW-ISA. Go to their web site and look at their list of consulting arborists. You can also link to the American Society of Consulting Arborists to look for a Registered Consulting Arborist in your area. An experienced consultant will be able to guide you or your lawyer about the available remedies in OR.