As human culture developed, forest fires increased. This association has been observed since the glaciers retreated, 10,000 years ago. It was thought that the increase in fires was a direct effect of agricultural expansion (the clearing of forests to open fields for farming). Well, now that the tenants were not all the blame. Researchers from the Far East have provided evidence that in certain regions responsible for the burning of forests was the war.
A bamboo forest in Vietnam.
Spontaneous fires are part of the natural cycle. As usual, there are hot and dry conditions. Hence, when they occur in cold and wet media, are attributed to the abundance of combustible materials, or human action. Humans have had a lot to do with the vagaries of the flames. No need to remember their role in the transition from nature to culture, either to defend the cattle, cooking, heating or woodland clearing with a view to farming. The intensification of human bustle subsequent retreat of the glaciers caused the fire regimes begin to disconnect from the weather.
For the scientists identify which has cost them of all human activities was instrumental in the growth of forest burning. A research published in the Proceedings gives a response based on the study of a limited area of Asia: the Red River delta (northern Vietnam), a densely populated area and covered with rice paddies.
Experts Vietnamese, Chinese and Japanese studied the fire regime in the delta said, over the past 5000 years u. From the ash layers of charcoal found in soil and their dating by mass spectrometry of carbon-14, were able to distinguish the periods marked by fire (ash rich) of the other phases (low ash). Thereby noticed that from the V century the concentration of coal ash increases, while decreasing the deposition of pollen from trees and climb the tree of the species, a clear sign of the link between fires and deforestation promoted by farmers .
The trend changed completely during the last 1500 years: the number, frequency and intensity of forest fires were fired. Six fire periods coincide exactly with the overthrow of the dynasty and the outbreak of wars and riots. The political turmoil had a negative impact on agriculture, as the recruitment of peasants deprived all fields of labor, then it can not be attributed to the higher strata ashen rice cultivation.
Five ways of attacking with fire
Everything indicates that the ash accumulated in that time span are the result of military action. There was already a long tradition in this sense in the neighboring empire, the Chinese. The great strategist Sun Tzu recorded five ways of attacking with fire: to burn soldiers in their camp, burning stores of food, transport of goods to burn, burn arsenals and shed fire between troops effects. Moreover, the Asian art of war included the use of fire to destroy fortifications, creating confusion in the enemy, provide communications and finally, as a sign of rebellion.
In conclusion, summarizes the experts, such as the advancement of agriculture is not related to the spread of fire, that the war was the key factor in forest fires in northern Vietnam during the Holocene late.
