Since time immemorial, trees have been central to many Indigenous cultures, including in Alaska. From towering totems to roomy canoes and elegant clan houses with crackling fires inside them, Indigenous cultures make ingenious use of nature’s abundance. Also since time immemorial, trees and the wood they provide were the primary source of heat for all humanity. We’ve been learning to manage forests and fire ever since – with varying degrees of success. Tok, Alaska is one such example of success. Surrounded by dense spruce trees, the region around Tok has become an annual tinderbox waiting to catch fire with increasingly drier summers brought on by climate change. Thousands of acres of spruce stands burn each summer, sometimes imperiling the communities they surround. Tok’s solution is to cut a wide fire break strategically around their community and use the harvested wood to heat their schools and greenhouses, plus make a little electricity on the side.
Now their community is safer from seasonal fire risk and is saving a lot of money by heating with local wood instead of imported heating oil. Combustion releases carbon dioxide into the atmosphere, whether in thick billowing plumes from wildfires, or in the relatively clean emissions from Tok’s high temperature industrial boilers. It made sense for the community of Tok to displace non-renewable old carbon in heating oil with the renewable new carbon found in young trees.
This lesson explores how different trees have different amounts of biomass and carbon in them. Trees remove carbon from the atmosphere (in the form of CO2 through photosynthesis) and use it to build their mass. That carbon is then released when it burns or decomposes. Foresters use allometry to calculate the amount of biomass in trees to estimate the total biomass in a forest. Forest managers, including private landowners, can estimate the value of their forest for heating from the biomass energy. NASA also uses information about biomass to better understand how ecosystems are storing or releasing carbon in the Global Ecosystem Dynamics Investigation (GEDI) mission. Consider also how trees have provided varied other benefits to humans such as cultural significance of totem poles, renewable building materials, salicylic acid from willows, cooling effects in urban environments, nutrition from birch syrup, improved mental health, shading for water sheds, and more.