(wa, Usa) Developer Of Adjacent Property Destroyed The Roots Of 3 Massive Fir Trees On The Edge Of Our Property. We Hired A Certified Arborist Who Reported They Are Too Damaged To Be Saved And Need Removal. What's The Best Course Of Action Now?

The Fir trees are at least 50 years old with 25-30 inch diameter trunks and were in good health, ignoring the new damage from the developer. The developer had excavated the adjacent lot about 2-3 feet deep, visibly destroying roots that are probably 6+ inches in diameter, up to approximately 3 feet horizontal from the base of the tree.

It appears that the city that we reside in has multiple relevant codes regarding preserving existing trees which were obviously not followed by the developer or the city's review process. How should we proceed?