Fire Disturbance in Arctic and Boreal Ecosystems: Terrestrial Ecosystems Meeting April 2024

This meeting of the Terrestrial Ecosystems Community of Practice focused on fire disturbance in Arctic and boreal ecosystems.
Fernanda Santos (Oak Ridge National Laboratory) presented "Fire impacts on soil C dynamics." The impact of Arctic fire regimes such as frequency and time since last fire on permafrost carbon remains a critical uncertainty in Earth system models. Santos presented an ongoing study that examines the effects of fire frequency and time since last fire on soil carbon fluxes and pools measured from the organic layer of an Arctic tussock tundra ecosystem. Data generated from this project can be incorporated into ecosystem models to advance our understanding of how soil C storage and dynamics will respond to shifts in wildfire regimes under a changing climate.
Dong (Tony) Chen (University of Maryland) presented "A burned area product developed specifically for circumpolar boreal forests and tundra." While several global burned area products exist for mapping wildfires in boreal and tundra zones, research indicates a tendency to underestimate burned areas in the Arctic. Leveraging an algorithm previously prototyped, Chen and colleagues have developed the Arctic Boreal Burned Area (ABBA) product, delineating wildfires across the circumpolar boreal forests and tundra since 2002 at a resolution of 500 meters. This enhanced performance can be attributed to Arctic-specific adjustments embedded within ABBA, such as comprehensive mapping of burn scars utilizing imagery from the spring subsequent to fire outbreaks. Given the pivotal role of burned area in determining wildfire impacts, Chen's findings suggest that wildfires in high northern latitudes may exert a significantly greater influence on Earth's systems than previously envisaged.
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Thumbnail photo: Yasunori Matsui/NPS

[@-LightningRod-]

unleash the Tundrafires !

[@vthilton]

Save Our Planet Now!

[@martiansoon9092]

@11:40 Hmmm... Few questions... And notes.
Are the first years after fire releasing most carbon to the air? This happens when rewetting dried peatlands. It is estimated that first few years release may emit as much carbon as the peatland takes in coming centuries. After few years there is no significant caron loss from wet peatland. If your samples are 3-4+ years old, the vegetation growth is taking the carbon for their own processes, but significant amounts of carbon is lost before vegetation growth. Also fire itself releases loads of carbon.
Does more active layer just mean more bacteria and vegetation growth? Does deeper active layer even mean more carbon releases or does it happen in the top layer mostly?
Also these are not the same what happens under the permafrost, because there is no significant active layer that may reduce the amount of generated gases. When this lid is penetrated it makes single point leaks where consentrations are high (often seen near lakes and other water bodies)..
I even think that one of the worst CO2e emissions comes from peatland that seasonally dries up and then has heavy rains or other watertable rising event. This means lots of decomposting under the water and large methane flux. When this happens once a year, the flux is huge.