The Tactical Mutual Aid Channel (TMAC) plan is an LA County Fire creation that complies with state, local and other groups as much as possible. There is a UHF version, and a VHF version. The thought being if every fire rig in the county has a radio with both, everyone will be able to communicate.
I believe the LA County V TMAC encompasses all the CalFire, USFS, NIFC channels, and some of the Verdugo agency radios are older with not enough memory.
I would love to see an updated 2008 listing for UHF and VHF