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| Titel |
Recovery of soil carbon and nitrogen pools following forest fires in eastern Lapland, Finland. |
| VerfasserIn |
K. Koster, J. Pumpanen, F. Berninger |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250071173
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| Zusammenfassung |
| Forest fires have been the dominant disturbance regimes in boreal forests since the last Ice
Age. Fire is the primary process which organizes the physical and biological attributes of the
boreal biome and influences energy flows and biogeochemical cycles, particularly the carbon
and nitrogen cycle. Forest fire activity is expected to increase significantly with changing
climate, acting as a catalyst to a wide range of ecosystem processes controlling carbon
storage in boreal forests.
We compared the initial recovery of carbon (C) and nitrogen (N) pools and dynamics
following fire disturbance in Scots pine (Pinus sylvesteris) stands in the boreal forests of
eastern Lapland (Värriö Strict Nature Reserve), Finland, by sampling soils and measuring
soil respiration from sample plots established in a chronosequence of different forest sites
with 4 age classes, ranging from 2 years to 150 years after fire disturbance (2, 40, 60, 150
years after fire). The sites are situated north of the Arctic Circle, near to the northern
timberline at an average of 300 m altitude.
The overall/total C and N contents in the first 10 cm of the topsoil (all soil layers taken
into consideration) were highest on old areas (fire 150 years ago) and lowest on
new areas (fire 2-40 years ago). The highest C pools (1071 g m-2) were measured
on old areas from top soil horizons (consisting of decomposing litter). The total
C pool was at the old site was 2329 g m-2. The area where the fire was 2 years
ago had the lowest total C pools, 1550 g m-2 respectively. The lowest C pools
were measured from area where the fire was 60 years ago, and from B horizon,
where the amount of C was 103 g m-2.When we compared the total C pools, the
newly burned areas (areas where the fire was 2 – 40 years ago) formed one group
(had similar values of total C) and old areas (areas where the fire was 60-150 years
ago) formed another group with similar values. Same tendencies occurred also
in total N pools, where we had lowest values where the fire was recently and the
highest values in old areas. These results are also correlating to the soil respiration
measurements, where we had lowest values of soil respiration in areas where fire was 2 years
ago (0,047 mg CO2 s-1 m-2) and highest values in old areas (0,144 mg CO2 s-1
m-2).
Our preliminary results show that forest fire has a substantial effect on the C and N pool
in the litter layer decaying forest top soil layer, but not in the humus layer and in mineral soil
layers. Soil respiration and biomass development showed similar chronological response to
the time since the forest fire indicating that substantial proportion of the respiration was
originating from the very top of the soil. |
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