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| Titel |
Ground vegetation reduces forest floor net CH4 uptake in a boreal upland forest |
| VerfasserIn |
Mari Pihlatie, Antti-Jussi Kieloaho, Elisa Halmeenmäki, Kira Ryhti, Jussi Heinonsalo |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250141435
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| Publikation (Nr.) |
 EGU/EGU2017-4945.pdf |
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| Zusammenfassung |
| Boreal upland forests are considered as an important sink for the greenhouse gas methane
(CH4) due to CH4 oxidizing microbes in the soil. Recent studies have reported significant
CH4 emissions from trees in both upland and wetland forests, however, contribution of
ground vegetation to the net CH4 exchange has not been assessed. As the processes and
process drivers of the CH4 emissions from vegetation are still poorly understood,
partitioning the CH4 exchange in forest ecosystems to soil, ground vegetation and
trees is a way to improve our understanding of the CH4 cycling processes in forest
ecosystems.
We measured the forest floor CH4 exchange at a Scots pine dominated boreal
upland forest in Southern Finland (SMEAR II station) during the growing season
2015. The forest floor consisted of mostly shrubs of bilberry (Vaccinium myrtillus),
lingonberry (Vaccinium vitis-idaea), heather (Calluna vulgaris), and forest floor
mosses (Pleurozium schreberi, Hylocomium splendens, and Dicranum polysetum).
We measured the CH4 fluxes using transparent chambers under three vegetation
treatments: normal vegetation (normal), shrubs only (shrubs), and non-vegetated
(cut), and under three soil trenching treatments: control, 50 μm mesh (roots of trees
and shrubs excluded), and 1 μm mesh (roots of trees and shrubs, and microbes
excluded).
Forest floor acted as a sink of CH4 in all the vegetation and trenching treatments.
Presence of ground layer vegetation significantly reduced the forest floor CH4 uptake,
whereas soil trenching did not affect the CH4 exchange. Over the period of May – October
2015, the mean forest floor CH4 fluxes were -53.7 (± 3.1 SE), -96.7 (± 3.7), and -91.4 (±
4.3) μg CH4 m2 h−1 from normal, shrubs and cut treatments, respectively. The presence of
ground vegetation hence nearly halved the forest floor CH4 uptake compared to the shrubs
only and cut treatments. As the largest difference between normal and shrubs treatments were
the absence of mosses, our findings suggests that especially mosses play an important role in
the forest floor CH4 exchange as their removal drastically increased the net CH4 uptake. |
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