If your parcel abuts property that is maintained by the County of Nevada and there are dead or hazardous trees on their parcel, they can be contacted at the following:

County of Nevada – Department of Public Works
950 Maidu Avenue, Suite 170
Nevada City, CA 95959
(530) 265-1411
http://www.mynevadacounty.com/nc/cda/pw/Pages/Home.aspx