Krycklan, Sweden, 1980 -

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The Krycklan Catchment Study (KCS) is located approximately 50 km northwest of Umeå city in northern Sweden (64°, 14′N, 19°46′E). It is characterised by a natural mosaic of boreal landscapes consisting of forests, mires, streams and lakes that make up 70% of the area in Sweden, and which is representative of 30% of the world’s forest cover. Research in the catchment was initiated in 1980 at the Svartberget subcatchment (Nyänget or catchment 7 (C7)) which consists of a 100-year-old mixed forest located at the heart of KCS. A few years later in 1984, the research area expanded to include the upstream forest (Västrabäcken, C2) and mire-dominated (Kallkälsmyren, C4) sub-catchments of Svartberget where monitoring was also done. The recognition of the need to work at the landscape scale when addressing the influence of climate on aquatic ecology led to the expansion of the 6800-ha Krycklan catchment in 2002. This expansion then included 12 other partly nested sub-catchments, all varying in size, and landscape composition.

Krycklan from above
Krycklan forest showing ICOS Tower

Catchment size[edit]

The current 6800 ha Krycklan catchment consists of 16 monitored sub-catchments, of which six are periodically monitored while the remaining ten are part of the long-term water monitoring program for hydrology and biogeochemistry. These catchments vary in size from as small as 12 ha to as much as 20 ha with varying compositions of wetlands, forests and lakes. The establishment of the 150 m ICOS (Integrated Carbon Observation System) for CO2 dynamics and water vapour measurements has further increased the size of the footprint from KCS in Scandinavia.

Krycklan boardwalk through forest


The climate is characterized as a cold temperate humid type with persistent snow cover during the winter season. The 30-year mean annual temperature (1991–2020) is 2.2 °C, January −9.5°C, and July +14.7°C, mean annual precipitation is 614 mm, and annual mean runoff is 311 mm, giving an annual average evapotranspiration of 303 mm. Above and below-ground climate data have been monitored since 1980 as part of a reference monitoring program. Standard meteorological variables are monitored following World Meteorological Organization (WMO) recommendations and additional variables of particular research interest. In total, approximately 100 variables are automatically measured with a time resolution of 10 min or hourly collection. Another 20 variables, including phenological observations, are manually recorded.

Geology, Topography and Vegetation/Land use[edit]

Bedrock in KCS is dominated by Svecofennian metasediments/metagraywacke (94%) with 4% acid and intermediate metavolcanic rocks and 3% basic metavolcanic rocks. Quaternary deposits are dominated by till (51%) and sorted sediments (30%). The catchment ranges in elevation from 114 to 405 m above sea level (a.s.l.). The region was glaciated and has undergone substantial isostatic rebound following the last deglaciation. The highest postglacial coastline therefore traverses the catchment at approximately 257 m a.s.l dividing the catchment into two distinctly different areas. At higher altitudes the quaternary deposits are dominated by till and peat; at lower altitudes, postglacial sedimentary deposits dominate. In the till soils, well-developed iron podzols dominate the forest floor soils, but near the stream channels, the organic content increases, forming a riparian peat zone along the streams. Forest covers 87% of the catchment, mires 9%, and thin soils and rock outcrops 7% and 1%, respectively. The land use is dominated by forestry, approximately, 25% of the Krycklan catchment has been protected since 1922, but most of the other area is second-growth forest. Other than forestry which results in approximately 1% of the area being clear-cut every year, human impact is low with only 2% arable land and a population in the catchment of less than 100 people.

Krycklan forest stream C2
Krycklan wetland C4

Context of investigation[edit]

The research in the area started over 100 years ago to study the effects of paludification on forestry. When the new field station was established in Svartberget in the late 1970s, the research focus was on forest hydrology and biogeochemical cycling. This early work was followed in the 1990s by a decade of more intensive work on the role of acid deposition in stream water chemistry. Results from the research contributed to new views of anthropogenic acidification and natural acidity in organic carbon-rich boreal waters.

Following this, the research scope expanded substantially to include more research on biogeochemistry, carbon cycling, hydrology, GIS landscape analysis and ecology. Intensive work initiated on the connection between soils and surface waters led to a more process-based understanding of the regulation of streamwater chemistry across boreal landscapes.

In recent years, KCS transformed into a unique experimental platform for testing pure and applied research questions in a natural environment. The platform is continuously attracting new scientific projects such as several strong research environments, but has also resulted in direct collaboration with the Swedish Nuclear Waste Program, Swedish EPA, Sveaskog and others.

Today research in the catchment combines state-of-the-art approaches to study the grand challenges of how climate change affects and will affect ecosystem processes across different boundaries from soils to atmosphere. It also hosts a wide range of infrastructure including ICOS, RADAR-Tower, ACTRIS, SITES water, and forest based experimental programs. KCS also provides a platform for modelling long-term and short-term forest management scenarios and AI modelling of landscape features.


Hydrology, Soil Water, Stream Water Chemistry, Biogeochemistry, Soil Frost Manipulation, Riparian Zones, Mires, Ground Water, Temperature, Soil Moist, Lidar, GIS, Ecology and more.

Krycklan sampling stream water
Krycklan water quality sampling
Krycklan sampling lake C5 in winter

Links to project webpages[edit]

Krycklan Catchment Study

Part of a Unit for field-based research at the Swedish University of Agricultural Science.

Part of the Integrated Carbon Observation system ICOS.

Part of Swedish Infrastructure for Ecosystem Sciences SITES

Key publications[edit]

1. Lupon, A., Gómez-Gener, L., Fork, M. L., Laudon, H., Martí, E., Lidberg, W., & Sponseller, R. A. (2023). Groundwater-stream connections shape the spatial pattern and rates of aquatic metabolism. Limnology and Oceanography Letters, 8(2), 350-358.

2. Peichl, M., Martínez-García, E., Fransson, J. E. S., Wallerman, J., Laudon, H., Lundmark, T., & Nilsson, M. B. (2023). On the uncertainty in estimates of the carbon balance recovery time after forest clear-cutting. Global Change Biology, 29(15), E1-E3.

3. Laudon, H., Lidberg, W., Sponseller, R.A., Maher Hasselquist, E., Westphal, F., Östlund, L., Sandström, C., Järveoja, J., Peichl, M., Ågren, A.M., 2022. Emerging technology can guide ecosystem restoration for future water security. Hydrological Processes 36.

4. Gutierrez Lopez, J., Tor-ngern, P., Oren, R., Kozii, N., Laudon, H., Hasselquist, N.J., 2021. How tree species, tree size, and topographical location influenced tree transpiration in northern boreal forests during the historic 2018 drought. Global Change Biology 27, 3066–3078.

5. Laudon, H., Hasselquist, E.M., Peichl, M., Lindgren, K., Sponseller, R., Lidman, F., Kuglerová, L., Hasselquist, N.J., Bishop, K., Nilsson, M.B., M. Ågren, A., 2021. Northern landscapes in transition: Evidence, approach and ways forward using the Krycklan Catchment Study. Hydrological Processes 35.

6. Tiwari, T., Sponseller, R., Laudon, H., 2021. The emerging role of drought as a regulator of dissolved organic carbon in the boreal landscapes. Nature communications.

7. Gómez-Gener, L., Lupon, A., Laudon, H., Sponseller, R.A., 2020. Drought alters the biogeochemistry of boreal stream networks. Nature communications 11.