| 1. |
- Bjarnadottir, Brynhildur, et al.
(författare)
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A young afforestation area in Iceland was a moderate sink to CO2 only a decade after scarification and establishment
- 2009
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Ingår i: Biogeosciences. - 1726-4189. ; 6:12, s. 2895-2906
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Tidskriftsartikel (refereegranskat)abstract
- This study reports on three years (2004-2006) of measurements of net ecosystem exchange (NEE) over a young Siberian larch plantation in Iceland established on previously grazed heathland pasture that had been scarified prior to planting. The study evaluated the variation of NEE and its component fluxes, gross primary production (GPP) and ecosystem respiration (R-e), with the aim to clarify how climatic factors controlled the site's carbon balance. The young plantation acted as a relatively strong sink for CO2 during all of the three years, with an annual net sequestration of -102, -154, and -67 g C m(-2) for 2004, 2005, and 2006, respectively. This variation was more related to variation in carbon efflux (R-e) than carbon uptake (GPP). The abiotic factors that showed the strongest correlation to R-e were air temperature during the growing season and soil water potential. The GPP mostly followed the seasonal pattern in irradiance, except in 2005, when the plantation experienced severe spring frost damage that set the GPP back to zero. It was not expected that the rather slow-growing Siberian larch plantation would be such a strong sink for atmospheric CO2 only twelve years after site preparation and afforestation.
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| 2. |
- Bjarnadottir, Brynhildur
(författare)
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Carbon stocks and fluxes in a young Siberian larch (Larix sibirica) plantation in Iceland
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The understanding of how forests function with respect to carbon (C) balance and its interaction with the climate system is a fundamental question in climate change research. Another important question is how large the sink for CO2 is in northern forests and how it varies with forest type, management, stand age and with external factors, such as climate variability. According to the Kyoto Protocol, C sequestration of all afforested areas since 1990 is to be deducted from the national GHG emissions. It is however highly uncertain when such young plantations become net sinks for CO2, especially if some major site preparation has been applied. The main aim of the present thesis was to evaluate the effect of afforestation on ecosystem C dynamics. For this, eddy covariance measurements of net ecosystem exchange (NEE) were made during three years over a Siberian larch (Larix sibirica) plantation with typical site conditions for afforestation in Iceland; previously grazed heathland that was site-prepared and planted in 1991-1992 and was therefore a ‘Kyoto-forest’. Additional studies took place in a comparable treeless sites and in different age-classes of Siberian larch, Sitka spruce (Picea sitchensis) and lodgepole pine (Pinus contorta), which are all commonly used in afforestation in Iceland. The young Siberian larch plantation acted as a relatively strong sink for CO2, with NEE of -375, -566 and -245 g CO2 m-2 for years 2004, 2005 and 2006, respectively. The observed annual variation in NEE was more related to variation in the carbon efflux (Re) than in the carbon uptake (GPP). Air temperature and soil water potential showed the strongest correlation to annual changes in Re. The GPP was lower in 2005, when the plantation experienced severe spring frost damage, but that was also the year with the highest NEE. Stock-change measurements supported the results of the eddy covariance flux measurements, indicating a mean annual sequestration of -673 g CO2 m-2, year-1. They indicated largest change in belowground C-stocks, in the fine root biomass and soil organic matter, not in aboveground C-stocks that generally is the main focus of carbon inventories. The chronosequences in 10-50 year old plantations showed similar increase in soil C stocks following afforestation as the main study site.
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| 3. |
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| 4. |
- Hammarsten, Maria, et al.
(författare)
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Utomhuspedagogik i Sverige och på Island
- 2022
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Föreläsningen belyser pedagogisk utomhusundervisning med olika förutsättningar. ”Kläder efter väder”, fri lek eller pedagogisk utomhusundervisning? Visst är det lite kaosartat när eleverna ska ut till en annan lärande arena, när de precis har socialiserats in till klassrumsundervisning. Forskning visar att en växelverkan mellan olika undervisningsmiljöer är att föredra för elevers lärande och utveckling. Hur kan utomhuspedagogik bedrivas på Island där det inte finns någon direkt ”skog” med träd? Välkommen du som lärare eller arbetar inom pedagogisk verksamhet, och bli inspirerad och få nya verktyg till din egna undervisning.
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| 5. |
- Jauhiainen, Jyrki, et al.
(författare)
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Reviews and syntheses: Greenhouse gas emissions from drained organic forest soils – synthesizing data for site-specific emission factors for boreal and cool temperate regions
- 2023
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Ingår i: Biogeosciences. - 1726-4170 .- 1726-4189. ; 20:23, s. 4819-4839
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Tidskriftsartikel (refereegranskat)abstract
- We compiled published peer-reviewed CO2, CH4, and N2O data on managed drained organic forest soils in boreal and temperate zones to revisit the current Tier 1 default emission factors (EFs) provided in the IPCC (2014) Wetlands Supplement: to see whether their uncertainty may be reduced; to evaluate possibilities for breaking the broad categories used for the IPCC EFs into more site-type-specific ones; and to inspect the potential relevance of a number of environmental variables for predicting the annual soil greenhouse gas (GHG) balances, on which the EFs are based. Despite a considerable number of publications applicable for compiling EFs being added, only modest changes were found compared to the Tier 1 default EFs. However, the more specific site type categories generated in this study showed narrower confidence intervals compared to the default categories. Overall, the highest CO2 EFs were found for temperate afforested agricultural lands and boreal forestry-drained sites with very low tree stand productivity. The highest CH4 EFs in turn prevailed in boreal nutrient-poor forests with very low tree stand productivity and temperate forests irrespective of nutrient status, while the EFs for afforested sites were low or showed a sink function. The highest N2O EFs were found for afforested agricultural lands and forestry-drained nutrient-rich sites. The occasional wide confidence intervals could be mainly explained by single or a few highly deviating estimates rather than the broadness of the categories applied. Our EFs for the novel categories were further supported by the statistical models connecting the annual soil GHG balances to site-specific soil nutrient status indicators, tree stand characteristics, and temperature-associated weather and climate variables. The results of this synthesis have important implications for EF revisions and national emission reporting, e.g. by the use of different categories for afforested sites and forestry-drained sites, and more specific site productivity categories based on timber production potential.
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| 6. |
- Jauhiainen, Jyrki, et al.
(författare)
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Reviews and syntheses: Greenhouse gas exchange data from drained organic forest soils-A review of current approaches and recommendations for future research
- 2019
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 16:23, s. 4687-4703
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Tidskriftsartikel (refereegranskat)abstract
- © Author(s) 2019. Drained organic forest soils in boreal and temperate climate zones are believed to be significant sources of the greenhouse gases (GHGs) carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), but the annual fluxes are still highly uncertain. Drained organic soils exemplify systems where many studies are still carried out with relatively small resources, several methodologies and manually operated systems, which further involve different options for the detailed design of the measurement and data analysis protocols for deriving the annual flux. It would be beneficial to set certain guidelines for how to measure and report the data, so that data from individual studies could also be used in synthesis work based on data collation and modelling. Such synthesis work is necessary for deciphering general patterns and trends related to, e.g., site types, climate, and management, and the development of corresponding emission factors, i.e. estimates of the net annual soil GHG emission and removal, which can be used in GHG inventories. Development of specific emission factors also sets prerequisites for the background or environmental data to be reported in individual studies. We argue that wide applicability greatly increases the value of individual studies. An overall objective of this paper is to support future monitoring campaigns in obtaining high-value data.We analysed peer-reviewed public cations presenting CO2, CH4 and N2O flux data for drained organic forest soils in boreal and temperate climate zones, focusing on data that have been used, or have the potential to be used, for estimating net annual soil GHG emissions and removals. We evaluated the methods used in data collection and identified major gaps in background or environmental data. Based on these, we formulated recommendations for future research.
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| 7. |
- Ring, Eva, et al.
(författare)
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Mapping policies for surface water protection zones on forest land in the Nordic-Baltic region : Large differences in prescriptiveness and zone width.
- 2017
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Ingår i: Ambio. - Dordrecht : Springer. - 0044-7447 .- 1654-7209. ; 46:8, s. 878-893
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Tidskriftsartikel (refereegranskat)abstract
- The forest landscape across the Nordic and Baltic regions hosts numerous lakes and watercourses, which must be included in forest management. In this study, national policy designs regarding protection zones for surface waters on forest land were reviewed and compared for the Nordic countries, Estonia and Latvia. The focus was how each country regulates protection zones, whether they are voluntary or mandatory, and the rationale behind adopting a low or high degree of prescriptiveness. Iceland and Denmark had a low degree of policy prescriptiveness, whereas Norway, Estonia and Latvia had a high degree of prescriptiveness. Sweden and Finland relied to a large extent on voluntary commitments. The prescribed zone widths within the region ranged from 1 m to 5 km. The results indicated that land-use distribution, forest ownership structure and historical and political legacies have influenced the varying degrees of prescriptiveness in the region.
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| 8. |
- Sigurdsson, B D, et al.
(författare)
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Biomass and composition of understory vegetation and the forest floor carbon stock across Siberian larch and mountain birch chronosequences in Iceland
- 2005
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Ingår i: Annals of Forest Science. - : EDP Sciences. - 1286-4560 .- 1297-966X. ; 62:8, s. 881-888
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Tidskriftsartikel (refereegranskat)abstract
- Changes in understory biomass, forest floor carbon (C) stock and vegetation composition were studied in six age-classes of Siberian larch (Larix sibirica) and two age-classes of native birch (Betula pubescens) in Iceland. The ground vegetation was less in the larch during the thicket stage and in the old-growth birch compared to a treeless pasture. Understory biomass was strongly related to canopy gap fraction across forest stands (P < 0.001), but not to soil pH or soil C/N ratio. Increased mass of dead wood and alterations in vegetation composition increased the forest floor C-stock of older forests. The forest floor had reached as high C-stock as the pasture's ground vegetation in ca. 50 years in the managed larch plantations and in ca. hundred years in the unmanaged birch forest. This study clearly shows the importance of which time-step is used when changes in forest floor C-stocks are computed for afforestation areas.
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