C.S.F.S. is the Colorado State Forest Service. They are charged with extended firefighting on private land in Colorado. These are typically lands not owned by USFS or BLM, and for fires that cross a propeperty line or go past shift change. (OK that last part is a little sarcastic, but you get the idea)
They have no dedicated full time Firefighting crews. All of thier resources are "Call When Needed" (CWN) with resources placed strategically around the state.
Typical set up is a local Volunteer Department, either with a CSFS provided Engine, or thier own under contract, lead by a full time CSFS Employee. These are often available as a National Resource, and deployed as Engine Strike Teams.
They also provide Type II Handcrews, which have been known to call themselves "Hotshots" but are NOT Federally recognized Type I handcrews.
These seasonal employee's are utilized nationwide, year round, typically for 14 day deployment in the Rocky Mountain Region.
The original author of the thread is from California where CDF (some say that's for Coffee Doughnuts and Fusee's), The California Department of Forestry provides EXTENSIVE FIRE and EMS, not just limited to Wildland fires. CSFS is no where near that complex.