In this paper we analyzed the ignition of the wood samples subjected to the dynamic heat flux. The experimental setup was created on the base of the optical wave "Uran-1" with a radiation source. The intensity of the heat flux was changed during the experiment by moving the test sample along the optical axis of the elliptic reflector in the setup. Pine wood was used as the test samples. We received the delay times for ignition of pine wood during heating under conditions of the decreasing and increasing heat flux. The received data were compared with the data for a static heat flux.