My window view is pretty green, watching clouds bobbing over the tree canopy to keep us all moisturized. Evening clouds, the low angle of the sun in the northern hemisphere can turn this view into dramatic scenes in this otherwise peaceful rural village, where cows moo and deer bleat and bellow. The tree canopy already turned black, the sun’s energy reflecting from the atmospheric scenery into dark blues and blazing reds.
Trees, majestic beings, pumping moisture around our globe continuously, almost quietly, forming clouds that can be transported by circulating winds. All the while their trunks record what happened during their lifetime, collectively forming the prototype BIG data that we have learned to read and interpret to a certain extent through the science of dendrochronology and dendroclimatology. The number of rings can give us an idea how old they are, the thickness of the rings providing us some information on how fast they were growing, the temperature/moisture relationships at the time of growth. Archival beings, even though they stand up straight, non-violent, they get into trouble sometimes. Forest Fires. Wildfires have happened throughout their lifetime, it can form scars on their trunks and become part of their archive. Trees have adapted to minimize trouble. Some trees, like the cork oak, are protected by their fire retardant bark. Heat and low moisture conditions can makes sparks fly and ignite a local fire, but after a burn, new life can rise from the ashes.
Ever since plants started to grow on the Earth’s land surfaces, fires have been part of the game, it happens in the thin boundary layer where the Earth interacts with its atmosphere, influencing Earth’s ecosystems since at least 420 million years ago, when our atmosphere reached oxygen levels high enough for spontaneous combustion to take place, ignited by lightning and other sources.
Wild fires burn commonly through the understory, leaving mature trees scarred, but living. The burn scars, combined with tree ring data, present a record of wildfire behavior.
“Natural forests are not a continuous expanse of old trees. Forest fires create a mosaic of burnt and unburnt areas, shaping the species composition and the age distribution of the forest. Fires open up the tree canopy, letting light in, releasing nutrients to the understory, and aiding regrowth. Charcoal changes soil structure, and charred tree trunks become habitats of great importance for the biological diversity of the forest—both above and below ground. Many rare species, especially fungi and insects, depend on the variation forest fires create”, according to scientists from the Norwegian Institute of Bioeconomy research.
Fast forward, wildfires are raging around the globe today like never before, hotspots like Australia, California, Brazil, Indonesia and Portugal, leading to record loss of tree cover. Not only that, their function to absorb heat trapping gasses when they are alive, turns around to emit those gases, contributing to more heat, spiraling in troublesome direction.
What is new, the atmosphere has changed over time and there were probably times with more vegetation and more oxygen for sure. It is hard to know, since we have only started to keep instrumental records since a little over a hundred years, when we also started with fire management, preventing wildfires to keep our population safe from fire hazards and concentrate our trees in tree stands, like reservations. This has however lead to a strange situation. Many of today’s forest reserves have never been as unnatural as they are today, which, it turns out, is burning our forests in novel, ‘truly unusual’ ways, burning into the canopies. How do we know…?
Fire anthropologist (yes anthropologists are a varied bunch) Roos and his colleague Swetnam constructed a model to analyze 1500 years of climate and fire patterns. Droughts and rising temperatures have been part of that record and mega fires like our present ones, could have possible happened, yet they didn’t. They suggest that over the last century, live stock grazing and firefighting, which in combination have created more dense forests that are more vulnerable than ever to extreme droughts.
I enjoy my green view, fully aware that I am in ‘cow land’ where grazing lands, are interspersed with forest stands, well managed, tree reservations. The last few years summer droughts have caused problems already, and summer temperatures are rising to heights that we have never measured before since we started measuring in the early 20th century. Like many things in our modern lives, trees are managed and manipulated. Trees know better, reservations are not a good idea.
https://phys.org/news/2017-03-fire-scarred-trees-years-natural-cultural.html
https://www.sciencedaily.com/releases/2012/05/120516120304.htm
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