Experimental tests were carried out with an adapted bench-scale mass loss calorimeter (MLC) and also in an outdoor wind tunnel to estimate the heat release rate (HRR) of a forest fuel bed. The MLC apparatus uses a calibrated thermopile to quantify the HRR, as an alternative to the classical measurement of oxygen consumption due to combustion. Additional calibration of thermocouples to measure gas temperatures enabled estimation of HRR in experimental burnings conducted in the wind tunnel. The results showed a reasonable agreement between peak HRR (PHRR) values obtained in the MLC and in the wind tunnel, and also demonstrated that PHRR was significantly affected by the wind speed and the rate of spread. The proposed procedure is potentially useful as an initial step in monitoring HRR in outdoor forest fire experiments.