The U.S. Forestry Service requires 1500 t.t., a Pt. 135 VFR checkride, and a checkride with one of their check airmen before you can pilot a 172 for them.
You might check with your state's Division of Natural Resources, Game and Fish, or whatever they call it where you are to learn who the contractors are. The state requirements for fire patrol\other types of survey flights probably are less stringent.
If you're in Michigan, try calling the airport manager at Roscommon Co. Conservation airport. The state DNR flies a lot of fire patrols out of that airport. He/She could probably give you some information that would help you locate the people you need to send a resume to.
The flight school I worked for in N.W. Arkansas flew a contract for the Arkansas Game and Fish department. They'd send us out for a maximum of two hours, average twice a week to count fishermen on a particular lake. To my knowledge, there was no minimum time requirement, but only the school's flight instructors flew the flights.
Good luck!