Short and long term effects of forest fires on the stability of carbon pools in the arctic permafrost and subarctic forests (ARCTICFIRE)

Regions: Gwich'in Settlement Area, Dehcho Region

Tags: physical sciences, permafrost, climate change, soil chemistry, forest fire, carbon, nitrogen

Principal Investigator: Koster, Kajar (1)
Licence Number: 16359
Organization: University of Helsinki
Licenced Year(s): 2018 2015
Issued: Jul 11, 2018
Project Team: Kajar Köster (Team leader, PI, University of Helsinki), Jukka Pumpanen (Professor, University of Eastern Finland), Frank Berninger (Associate Professor, University of Helsinki), Marjo Palviainen (Researcher, University of Helsinki), Xuan Zhou (PhD student, University of Helsinki), Heidi Aaltonen (PhD student, University of Helsinki), Christine Ribeiro Moreira de Assumpcao (PhD student, University of Helsinki), Huizhong Zang-Turpeinen (PhD student, University of Eastern Finland)

Objective(s): To study the short term and long term effects of different fire intensities on the decomposition of soil organic matter in northern boreal forests under changing fire regimes.

Project Description: The aim of this project is to study the short term and long term effects of different fire intensities on the decomposition of soil organic matter (SOM) in northern boreal forests under changing fire regimes.

The objectives are to: 1) explore the short and long term effects of forest fires with different intensity on above- and belowground biomasses; 2) explore changes in albedo, snow depths and post-fire above- and below ground temperatures; 3) find out how fire intensity and post fire vegetation succession is affecting the quantity, quality and decomposition of SOM; and, 4) clarify how SOM quality, fire intensity and time since fire are affecting the microbial biomass and biochemical processes driven by microbes.

The long term effects of fire will be studied based on chronosequences, where forest stands with similar soil type but different fire history will be compared to study biogeochemical changes following the fire. The study areas for this part of the project are located in northern boreal forests with continuous permafrost, in Northwest Territories and in Yukon, Canada. The study areas were created in summer of 2015 (in project financed by Academy of Finland) and consists of 4 age classes: fires in years 2012, 1990, 1969, control area with last fire more than 100 years ago (in total of 36 sample plots). The study sites of this project in NWT are located between Inuvik and Tsiigehtchic, along the Dempster Highway. The research will be conducted based on intensive field sampling at the fire chronosequence sites to study soil carbon (C)and nitrogen (N) stocks, soil carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes, soil permafrost depth, soil temperature and soil chemical and microbiological properties, vegetation changes, albedo, tree biomass and leaf area changes. The research team will use the field sampling for parameterizing process based soil organic matter decomposition and ecosystem C cycle models which will be used for simulating the long term effects of fire on soil and tree carbon stocks on a stand level.

On every area also continuous soil temperature measurements with thermistors and IButton temperature sensors (Maxim Integrated, San Jose, California, USA.) will take place, and soil moisture content measurements will be done with soil moisture sensors (Delta-T Devices Ltd, Cambridge, England).

The research team is working with different disturbances (wind, fire, herbivores, etc.) and their effects on soil properties and greenhouse gas (CO2, CH4, N2O) emissions. Thus, different educational opportunities for local involvement are possible such as seminars, lectures, collaboration in scientific data processing and writing.

Scientific papers will be sent to the Aurora Research Institute. The results will be also sent to Government of the Northwest Territories Environment and Natural Resources.

The fieldwork for this study will be conducted from July 26, 2018 to August 15, 2018.