At Stordalen, a replanted clear-cut site within the SITES station Skogaryd Research Catchment, a new 16 m high tower has been installed for continues monitoring of greenhouse gas emissions. The tower overlooks a young plantation forest, replacing a smaller tower that has been outgrown by the trees. At Stordalen, researchers from Lund university are measuring the net ecosystem exchange (NEE) of carbon dioxide (CO₂) at a clear-cut forest site using the time-tested Eddy Covariance (EC) method. The measurements started in 2012 directly following clear-cutting and have been running continuously since then. As the vegetation grows taller, the tower must be raised for continuous measurements above tree canopy. The tower was already raised in 2015 and now it is time for an even taller tower.

Preliminary results for the first decade after clear-cutting, indicate that Stordalen is a large CO₂ source to the atmosphere, and has not yet reached the point of carbon balance on an annual basis.  Since Stordalen has moist soil conditions, a large fraction of birch trees has been left at the site to help promote the growth of the planted spruce trees. These birches have been partially removed on several occasions. This complicates the data interpretation, and it is important to account for these harvesting operations when assessing the recovery time of the carbon fluxes at Stordalen. Ultimately, the measurements at Stordalen might contribute to the formulation of new ecological and economic goals, management plans and policies that guide the future use of the Swedish forests.

The next round of the joint AquaNet and AQUACOSM-plus experiments are kicking-off! This time around the experiments will take place at Asa Research Station and Svartberget Research Station with a focus on functional and compositional consequences of different salinity disturbance regimes on plankton communities. The experiment is a follow up to the GLEON Salt experiment in 2018 and will run from mid-June to the end of July.

The mesocosm experiments will be identically run at the two stations, which are both located in forested catchments. The contrast between geographical location (57.17N and 64.26 N), lake area (0.52 km2 and 0.04km2) and trophic status (Oligratrophic and Mesotrophic), respectively for Feresjön at Asa and Stortjärn at Svaretberget, will provide an interesting comparison for the study.

The Abisko Scientific Research Station field season started in earnest on June 1st. The station will be fully occupied in July, and the occupancy will remain high even in August and September. The ten-bed field hut in Latnjajaure will have researchers on-site throughout the summer.

The Director of the Swedish Polar Research Secretariat, Katarina Gårdfeldt, and parts of the government agency's advisory council recently visited the station. They also went to the Stordalen mire area near Torneträsk, about ten kilometres from Abisko. They were shown around and informed about ongoing continuous measurements, such as greenhouse gases, and current research projects.

The SITES 2023 Calendar theme is “Data in Focus”. The openly available data produced within SITES and stored on the SITES Data Portal is the “golden thread” of the infrastructure, allowing users access to ecosystem data that covers diverse habitats and climate zones across geographical gradients in Sweden. Each month follow along as we highlight a unique SITES dataset.  

SITES has three Thematic Programs that strengthen the collaboration within the network of stations in remote sensing, water monitoring and aquatic mesocosms. The Thematic Programs facilitate comparison between climate zones, landscape elements and management systems and offer open data from long-term monitoring and experimental installations.

This month the SITES Water Thematic Program is featured, which builds a unique long-term and well-coordinated measurement program where hydrological, physical, chemical, and biological parameters within lakes and streams are measured at seven SITES stations. As part of SITES Water, lake platforms are equipped with automated high frequency sensors that measures weather and climate variables above the lake (e.g. air temperature, humidity, wind speed) as well as physical variables within the lake (e.g. temperature, oxygen). The lake water temperature is measured at different depths, i.e. lake profile, which allows for the thermal structure of the lake over the year to be determined. The thermal structure of a lake plays an important role in the biogeochemical cycling and subsequent greenhouse gas emissions from the lake.

Link to Data: https://meta.fieldsites.se/objects/iHSmt3sLan6AhIm_DO5tV1h6

The graph shows sub-hourly water temperature at different depths in lake Erssjön over the year in 2020. Early in the year, the water temperature at different depths in the lake was similar but as air temperatures warmed in the spring, a thermal stratification formed, where the warm surface water of the lake disconnected from the cooler bottom water. As the air temperatures cooled in the fall, the lake mixed and the water temperatures in the lake at different depths became similar again. The photo shows the lake platform on Erssjön, which is equipped with meteorological sensors above the lake and in situ aquatic sensors below the lake.  

At Stordalen, a replanted clear-cut site within the SITES station Skogaryd Research Catchment, a new 16 m high tower has been installed for continues monitoring of greenhouse gas emissions. The tower overlooks a young plantation forest, replacing a smaller tower that has been outgrown by the trees. At Stordalen, researchers from Lund university are measuring the net ecosystem exchange (NEE) of carbon dioxide (CO₂) at a clear-cut forest site using the time-tested Eddy Covariance (EC) method. The measurements started in 2012 directly following clear-cutting and have been running continuously since then. As the vegetation grows taller, the tower must be raised for continuous measurements above tree canopy. The tower was already raised in 2015 and now it is time for an even taller tower.

Preliminary results for the first decade after clear-cutting, indicate that Stordalen is a large CO₂ source to the atmosphere, and has not yet reached the point of carbon balance on an annual basis.  Since Stordalen has moist soil conditions, a large fraction of birch trees has been left at the site to help promote the growth of the planted spruce trees. These birches have been partially removed on several occasions. This complicates the data interpretation, and it is important to account for these harvesting operations when assessing the recovery time of the carbon fluxes at Stordalen. Ultimately, the measurements at Stordalen might contribute to the formulation of new ecological and economic goals, management plans and policies that guide the future use of the Swedish forests.

The next round of the joint AquaNet and AQUACOSM-plus experiments are kicking-off! This time around the experiments will take place at Asa Research Station and Svartberget Research Station with a focus on functional and compositional consequences of different salinity disturbance regimes on plankton communities. The experiment is a follow up to the GLEON Salt experiment in 2018 and will run from mid-June to the end of July.

The mesocosm experiments will be identically run at the two stations, which are both located in forested catchments. The contrast between geographical location (57.17N and 64.26 N), lake area (0.52 km2 and 0.04km2) and trophic status (Oligratrophic and Mesotrophic), respectively for Feresjön at Asa and Stortjärn at Svaretberget, will provide an interesting comparison for the study.

The Abisko Scientific Research Station field season started in earnest on June 1st. The station will be fully occupied in July, and the occupancy will remain high even in August and September. The ten-bed field hut in Latnjajaure will have researchers on-site throughout the summer.

The Director of the Swedish Polar Research Secretariat, Katarina Gårdfeldt, and parts of the government agency's advisory council recently visited the station. They also went to the Stordalen mire area near Torneträsk, about ten kilometres from Abisko. They were shown around and informed about ongoing continuous measurements, such as greenhouse gases, and current research projects.

The SITES 2023 Calendar theme is “Data in Focus”. The openly available data produced within SITES and stored on the SITES Data Portal is the “golden thread” of the infrastructure, allowing users access to ecosystem data that covers diverse habitats and climate zones across geographical gradients in Sweden. Each month follow along as we highlight a unique SITES dataset.  

SITES has three Thematic Programs that strengthen the collaboration within the network of stations in remote sensing, water monitoring and aquatic mesocosms. The Thematic Programs facilitate comparison between climate zones, landscape elements and management systems and offer open data from long-term monitoring and experimental installations.

This month the SITES Water Thematic Program is featured, which builds a unique long-term and well-coordinated measurement program where hydrological, physical, chemical, and biological parameters within lakes and streams are measured at seven SITES stations. As part of SITES Water, lake platforms are equipped with automated high frequency sensors that measures weather and climate variables above the lake (e.g. air temperature, humidity, wind speed) as well as physical variables within the lake (e.g. temperature, oxygen). The lake water temperature is measured at different depths, i.e. lake profile, which allows for the thermal structure of the lake over the year to be determined. The thermal structure of a lake plays an important role in the biogeochemical cycling and subsequent greenhouse gas emissions from the lake.

Link to Data: https://meta.fieldsites.se/objects/iHSmt3sLan6AhIm_DO5tV1h6

The graph shows sub-hourly water temperature at different depths in lake Erssjön over the year in 2020. Early in the year, the water temperature at different depths in the lake was similar but as air temperatures warmed in the spring, a thermal stratification formed, where the warm surface water of the lake disconnected from the cooler bottom water. As the air temperatures cooled in the fall, the lake mixed and the water temperatures in the lake at different depths became similar again. The photo shows the lake platform on Erssjön, which is equipped with meteorological sensors above the lake and in situ aquatic sensors below the lake.