Fire severity effects on soil organic matter in northern Minnesota, USA
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FLAMMA. 6(1): 23-25.
Wildfire may cause major losses of forest soil organic matter and consequently limit soil nutrient availability and forest regeneration, although the characteristics of post-fire organic matter are also likely to influence these processes. The 2011 Pagami Creek wildfire in northern Minnesota was a historical fire event and resulted in a range of fire severity levels determined via remote sensing and field measurements. To evaluate the effects of fire severity on forest soil organic matter, we sampled soils immediately following fire in areas and quantified total soil carbon (C) and nitrogen (N) content using elemental analysis, and black (pyrogenic) C using nuclear magnetic resonance (NMR) spectroscopy. Forest floor C content decreased with fire severity, and there were no differences in forest floor N content among severity classes. Similarly, there were no differences in total C or N contents for mineral soil at 0-10 cm or 10-20 cm depths. All fire severity levels decreased C:N ratio relative to unburned reference areas for the forest floor and 0-10 cm mineral soil; however, there were no differences in C:N among severity levels. Results on pyrogenic C content will be presented. Our results indicate that fire effects on soil C and N contents are limited primarily to the organic soil layers, and that effects on mineral soil are minimal. Understanding the environmental effects of forest fire as a function of fire severity is critical for developing appropriate policies and practices for minimizing detrimental effects and managing fire-prone forests for long-term resilience.
KeywordsBlack carbon; Carbon; Forest; Pyrogenic carbon; Wildfire
Miesel, Jessica R.; Kolka, Randall K.; Townsend, Philip A.; Hockaday, William C. 2015. Fire severity effects on soil organic matter in northern Minnesota, USA. FLAMMA. 6(1): 23-25.