Living up there in the north valley, you may never need a trunk tracking scanner. Depending on what you want to listen to, you might need a digital scanner first. Federal channels are going digital and I've read here that includes some USFS and other agencies.
CHP is getting 700 MHz for some of their communications. On one hand 700 MHz is always supposed to be digital, but I don't think they are planning to be digital right now.
Trunk tracking; the closest places to you with trunked radio systems are Sacramento county, Redding and Nevada (including Reno).
Chico State University is about the only major agency on a TRS right now. It might not even be worth the price of a new scanner, if the campus police and fire depts. are still using their old VHF radios. There is no list of the "talk groups"; so you'll have to listen and figure them out. LTR systems are pain in the ass to program compared to Motorola or GE systems.