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Climate change has increased the area affected by forest fires each year in boreal North America. Increases in burned area and fire frequency are expected to stimulate boreal carbon losses. However, the impact of wildfires on carbon emissions is also affected by the severity of burning. How climate change influences the severity of biomass burning has proved difficult to assess. Here, we examined the depth of ground-layer combustion in 178 sites dominated by black spruce in Alaska, using data collected from 31 fire events between 1983 and 2005. We show that the depth of burning increased as the fire season progressed when the annual area burned was small. However, deep burning occurred throughout the fire season...
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Boreal forests contain significant quantities of soil carbon that may be oxidized to CO2 given future increases in climate warming and wildfire behavior. At the ecosystem scale, decomposition and heterotrophic respiration are strongly controlled by temperature and moisture, but we questioned whether changes in microbial biomass, activity, or community structure induced by fire might also affect these processes. We particularly wanted to understand whether postfire reductions in microbial biomass could affect rates of decomposition. Additionally, we compared the short-term effects of wildfire to the long-term effects of climate warming and permafrost decline. We compared soil microbial communities between control...
The U.S. Geological Survey project Fate of Carbon in Alaskan Landscapes(FOCAL) is studying the effect of fire and soil drainage on soil carbon storage in the boreal forest. This project has selected several sites to study within central Alaska of varying ages (time since fire) and soil drainage types. This report describes the location of these sampling sites, as well as the procedures used to describe, sample, and analyze the soils. This report also contains data tables with this information, including, but not limited to field descriptions, bulk density, particle size distribution, moisture content, carbon (C) concentration, nitrogen (N) concentration, isotopic data for C, and major, minor and trace elemental...
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Fire is a particularly important control on the carbon (C) balance of the boreal forest, and fire-return intervals and fire severity appear to have increased since the late 1900s in North America. In addition to the immediate release of stored C to the atmosphere through organic-matter combustion, fire also modifies soil conditions, possibly affecting C exchange between terrestrial and atmospheric pools for decades after the burn. The effects of fire on ecosystem C dynamics vary across the landscape, with topographic position and soil drainage functioning as important controls. The data reported here contributed to a larger U.S. Geological Survey (USGS) study, published in the journal Ecosystems by O’Donnell...
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One objective of the U.S. Geological Survey’s Fate of Carbon in Alaskan Landscapes (FOCAL) project is to study the effects of fire and soil drainage on soil carbon storage in boreal forests. For this purpose, the project has measured the soil carbon content in several chronosequences (time since disturbance) of various soil-drainage types. One such chronosequence near Delta Junction, Alaska was initially studied in 2000 and 2001. Additional sites in the Delta Junction area were sampled in 2006 to expand the number of stand ages represented in the chronosequence. This report describes these additional sites, as well as the procedures used to describe, sample, and analyze the soils. We also present data tables containing,...
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Peatlands in the northern permafrost region store large amounts of organic carbon, most of which is currently stored in frozen peat deposits. Recent warming at high-latitudes has accelerated permafrost thaw in peatlands, which will likely result in the loss of soil organic carbon from previously frozen peat deposits to the atmosphere. Here, we report soil organic carbon inventories, soil physical data, and field descriptions from a collapse-scar bog chronosequence located in a peatland ecosystem at Koyukuk Flats National Wildlife Refuge in Alaska.
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The influence of permafrost growth and thaw on the evolution of ice-rich lowland terrain in the Koyukuk-Innoko region of interior Alaska is fundamental but poorly understood. To elucidate this influence, the cryostratigraphy and properties of perennially frozen sediments from three areas in this region are described and interpreted in terms of permafrost history. The upper part of the late Quaternary sediments at the Koyukuk and Innoko Flats comprise frozen organic soils up to 4.5 m thick underlain by ice-rich silt characterised by layered and reticulate cryostructures. The volume of visible segregated ice in silt locally reaches 50 per cent, with ice lenses up to 10 cm thick. A conceptual model of terrain evolution...
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Fire is an important control on the carbon (C) balance of the boreal forest region. Here, we present findings from two complementary studies that examine how fire modifies soil organic matter properties, and how these modifications influence rates of decomposition and C exchange in black spruce (Picea mariana) ecosystems of interior Alaska. First, we used laboratory incubations to explore soil temperature, moisture, and vegetation effects on CO2 and DOC production rates in burned and unburned soils from three study regions in interior Alaska. Second, at one of the study regions used in the incubation experiments, we conducted intensive field measurements of net ecosystem exchange (NEE) and ecosystem respiration...
map background search result map search result map Controls on ecosystem and root respiration across a permafrost and wetland gradient in interior Alaska Cryostratigraphy and Permafrost Evolution in the Lacustrine Lowlands of West-Central Alaska Seasonal ice and hydrologic controls on dissolved organic carbon and nitrogen concentrations in a boreal-rich fen The effect of fire and permafrost interactions on soil carbon accumulation in an upland black spruce ecosystem of interior Alaska: implications for post-thaw carbon loss A dynamic organic soil biogeochemical model for simulating the effects of wildfire on soil environmental conditions and carbon dynamics of black spruce forests Soil data for a collapse-scar bog chronosequence in Koyukuk Flats National Wildlife Refuge, Alaska, 2008 Soil data from different-age Picea mariana stands near Delta Junction, Alaska Exploring the sensitivity of soil carbon dynamics to climate change, fire disturbance and permafrost thaw in a black spruce ecosystem The effect of soil drainage on fire and carbon cycling in central Alaska Interactive Effects of Fire, Soil Climate, and Moss on CO2 Fluxes in Black Spruce Ecosystems of Interior Alaska The role of mosses in ecosystem succession and function in Alaska's boreal forest Interactive effects of wildfire and permafrost on microbial communities and soil processes in an Alaskan black spruce forest The response of soil organic carbon of a rich fen peatland in interior Alaska to projected climate change Soil physical, chemical, and gas-flux characterization from Picea mariana stands near Erickson Creek, Alaska Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost Soil physical, chemical, and gas-flux characterization from Picea mariana stands near Erickson Creek, Alaska Controls on ecosystem and root respiration across a permafrost and wetland gradient in interior Alaska The role of mosses in ecosystem succession and function in Alaska's boreal forest Differential response of carbon fluxes to climate in three peatland ecosystems that vary in the presence and stability of permafrost Seasonal ice and hydrologic controls on dissolved organic carbon and nitrogen concentrations in a boreal-rich fen Soil data from different-age Picea mariana stands near Delta Junction, Alaska A dynamic organic soil biogeochemical model for simulating the effects of wildfire on soil environmental conditions and carbon dynamics of black spruce forests Interactive effects of wildfire and permafrost on microbial communities and soil processes in an Alaskan black spruce forest The response of soil organic carbon of a rich fen peatland in interior Alaska to projected climate change The effect of soil drainage on fire and carbon cycling in central Alaska Exploring the sensitivity of soil carbon dynamics to climate change, fire disturbance and permafrost thaw in a black spruce ecosystem Soil data for a collapse-scar bog chronosequence in Koyukuk Flats National Wildlife Refuge, Alaska, 2008 Cryostratigraphy and Permafrost Evolution in the Lacustrine Lowlands of West-Central Alaska Interactive Effects of Fire, Soil Climate, and Moss on CO2 Fluxes in Black Spruce Ecosystems of Interior Alaska The effect of fire and permafrost interactions on soil carbon accumulation in an upland black spruce ecosystem of interior Alaska: implications for post-thaw carbon loss