A fault-tolerant cooperative control (FTCC) strategy for cooperative unmanned aerial vehicles (UAVs) used in forest monitoring, fire detection and tracking is investigated in this paper. The proposed algorithm solves the problem of monitoring and detection of forest fires, even when fault occurs to one or more UAVs. During the search stage, the UAVs team moves in a certain formation shape, a distributed sliding mode formation control is designed to keep the desired formation shape during this stage. Once a fire is detected, another distributed reconfigurable controller is designed based on sliding mode control (SMC) to evenly distribute UAVs team around the elliptical fire perimeter in fault-free case. When one or more UAVs cannot continue their mission due to a fault or leaving from formation for refueling/recharging, an FTCC strategy will be deployed to decrease the effects of the changed formation condition and the faulty/absent UAV's tasks will be reassigned to the remaining healthy/operable ones. Therefore, the new formation will be reconfigured and the UAVs still be evenly distributed around the fire spot for best coverage of the fire site. Simulation results are used to demonstrate the effectiveness of the proposed algorithm using six degree-of-freedom (DOF) quadrotor dynamic models of UAVs.