Investigation on wood resistance of different tree species to fire at Caspian Forests of Iran

Wood resistance of forest species to fire has effective role in preventing forest fire development and expansion. Thus, the aim of this research was to study the tree species wood resistance to fire and to measure the time needed for complete wood burning, considering the wood’s moisture and bark. The trial was conducted under the Completely Randomized Experimental Design with six replicates, 10 forest species (Carpinus betulus, Alnus glutinosa, Parrotia persica, Fagus orientalis, Pterocarya fraxinifolia, Acer cappadocicum, Acer velutinum, Cupresus sempervirence var horizontalis, Quercus castaneifolia and Zelkova carpinifolia), two levels of wood moisture (dry and wet or natural moisture) and two barked and bark free treatments. The woods were burnt at 400°C and the time needed for complete burning was measured by a chronometer. The results showed that the resistance of wet woods to complete burning was 2.3 (Quercus castaenifolia) to 2.9 (Parrotia persica) times more than the dry woods. Carpinus betulus and Parrotia persica had the greatest and the lowest resistance to complete burning, respectively. Moreover, the resistance of Fagus orientalis, Acer cappadocicum, Acer velutinum and Zelkova carpinifolia to complete burning increased, respectively. Bark increased the resistance of some species to complete burning, for instance the time difference for complete burning of wet and dry woods of Fagus orientalis, Cupressus sempervirens var. horizontalis, Acer cappadocicum, Acer velutinum and Zelkova carpinifolia was 46, 82, 110, 116 and 169 seconds, respectively. Although Alnus glutinosa and Pterocarya fraxinifolia had high capacity to establish in sites with poor drainage, but they had a very low resistance to fire. Therefore, it is recommended to plant Fagus orientalis, Acer cappadocicum, Acer velutinum, Parrotia persica and Zelkova carpinifolia as an alive firebreak in areas with high fire risks (naturally and human related reasons), for instance near forest roads and tourism centers, for their capacity to prevent fire development and expansion