Oregon State University/Earth Island Research Center, U.S. Soldiers from the Phoenix Battalion, 102nd Armored Brigade, deployed to the site of a forest fire in Bicheon-dong, Donghae-si, Gangwon-do on the 7th, are conducting a fire-fighting operation. U.S. scientists have found that most of the carbon stored in the forest remains intact even when trees are burned to death in a forest fire. The research team emphasized that it is beneficial to the environment to let burned wood decompose on its own, rather than immediately destroying it.
The Oregon State University and the Earth Island Research Institute, a non-profit environmental group, announced on the 14th that after two large-scale wildfires in the Sierra Nevada Mountains of California, the United States, the burn rate of the large trees was only 5%.
Normally, trees absorb a large amount of carbon from the atmosphere through photosynthesis and store it in the body. However, if a forest fire occurs and burns, carbon dioxide, a major greenhouse gas, is released back into the atmosphere. The research team explained that by knowing the combustion rate of trees and the amount of carbon released from forest fires, it is possible to accurately understand the impact of carbon emissions in the atmosphere and to determine an appropriate forest management plan.
The Sierra Nevada Mountains that the research team investigated have suffered several major wildfires in history. In August 2013, about 104,131 hectares were burned, and in September 2020, about 145,269 ha of forest was engulfed in fire. The Sierra Nevada Mountains are known to be dominated by fir and pine trees. The sap of conifers such as pine trees burns easily and plays a role in spreading wildfires.
The research team used satellite data and lidar sensor measurement data to determine the size of trees according to the fire severity, tree species, and tree size in the Sierra Nevada Mountains, focusing on coniferous forests among the forest fires in August 2013 and September 2020. We have seen how different biomass burn rates are.
Mark Harmon, a professor of forest ecology and sociology at Oregon State University in the US, explained the intention of this study, saying, “In the case of large wildfires, the burning rate of trees is often overestimated.” The teams analysis showed that the rate of biomass burning decreased with decreasing fire severity and with larger trees. For example, it was found that small tree branches in areas with severe fires have a burning rate of 100% and 57% of small trees. This means that all parts of the twig were burned, and more than half of the twig was burned. Large trees, on the other hand, burned less than 5%. Since most of the surveyed area consisted of large trees, the overall burning rate of the affected area was also low.
The research team classified the overall rate of combustion in the surveyed area into two categories. One is the ‘Stand Level’, which divides the burn rate of all trees of various species and sizes according to fire severity ratings, and the other is the ‘Landscape Level’, which spans fire severity ratings. The average overall burn rate is shown. The research team analyzed that the burning rate was 0.1-3.2% at the stand level and 0.6-1.8% at the landscape level. Mark Harmon, professor of forest ecology and sociology at Oregon State University in the US, said, “In particular, trees at the border of a fire have a moderate fire severity and a low burning rate of less than 0.5%.”
The researchers emphasized the importance of maintaining older, mature trees that store more carbon in order to reduce greenhouse gas emissions. He also advises that allowing trees to decompose in nature and release carbon slowly is less exacerbated by the current greenhouse gas problem, rather than immediately removing and burning even dead trees.
Dominic Delasala, chief scientist for the Wild Heritage Project at the Earth Island Research Institute of America, said, “A simple estimate of carbon emissions from wildfires does not reflect the actual combustion rate properly” policy can be derived”. This study was conducted in the international scientific journal ‘Forest’ It was announced on the 27th of last month.