Visions from nature

Long-term ecological monitoring – a visit to LTER forest in Belgium

By Anders L Kolstad

Global change is threatening ecosystems across the worlds. Among the most important drivers are things like human-caused climate change, changes in historical land-use, and introduced species. The effect of these processes on ecosystems are often difficult to study and describe because it takes so long for them to become apparent, typically several decades. This is for example much longer than the average research project which typically last only 2-4 years. That’s why long time-series (10+ years) are so important for us to be able to say something about the cumulative effect of actions on the health of our forests, fields, oceans, mountains, and the other ecosystems.

This beech is equipt with a measurement device which registers the flow of the sap underneath the bark of the tree. The measurements are done every 15 minutes and is sent directly and wireless to the internet, day after day, year after year. With this, researcher kan say something about drough stress and how the forest is responding to climate change.
This beech is equipt with a measurement device which registers the flow of the sap underneath the bark of the tree. The measurements are done every 15 minutes and is sent directly and wireless to the internet, day after day, year after year. With this, researcher kan say something about drough stress and how the forest is responding to climate change. Photo: Anders L. Kolstad, NTNU University Museum, CC BY-SA 4.0

I conjunction with a large conference in Ghent (Belgium) in December I had the pleasure of joining a trip to the location of one such time-series, placed in a small forest outside of the same city. In Aelmoeseneiebos (bos means forest in Dutch) they have since 1993 registered climate data, rainwater and soil chemistry, plant litter quantity and nutrient contents, and more. In later years they’ve expanded to also continuously monitor the growth and water balance of individual beech and oak trees in the forest. Several other station like this one exists in Northern Europe. All their data is compiled and uploaded to a common web page where anyone can go to see how the trees are doing that day. All the data is also freely available to researches from anywhere in the world.

: The climate tower in Aelmoeseneiebos which registers all the necessary climate variables (temperature, precipitation, wind etc.) which are then used when one want to analyse the variation and ecosystem variables (plant growth, soil chemistry, drought responses, etc.) and relate these to climate.
The climate tower in Aelmoeseneiebos which registers all the necessary climate variables (temperature, precipitation, wind etc.) which are then used when one want to analyse the variation and ecosystem variables (plant growth, soil chemistry, drought responses, etc.) and relate these to climate. Photo: Anders L. Kolstad, NTNU University Museum, CC BY-SA 4.0

Aelmoeseneiebos is part of a larger network of ecological time series called LTER (long-term ecosystem research in Europe). Over 400 field stations are scattered across Europe and also includes sites that measure socio-ecological parameters. This project is a great example of what is possible when one is thinking long term, internationally, and interdisciplinary. Read more about LTER.

Rain water is collected in the vertical brown pipes and dead leaves fall from the trees above and are collected in the circular nets that you see in the picture. Reseachers from Ghent University take these samples to the lab and analyse them. By doing this over several decades (25 years so far) you can start to tease apart the between-year variation from the long trends in the data which are rather due to large scale patterns in for example pollution and climate and land-use changes.
Rain water is collected in the vertical brown pipes and dead leaves fall from the trees above and are collected in the circular nets that you see in the picture. Reseachers from Ghent University take these samples to the lab and analyse them. By doing this over several decades (25 years so far) you can start to tease apart the between-year variation from the long trends in the data which are rather due to large scale patterns in for example pollution and climate and land-use changes. Photo: Anders L. Kolstad, NTNU University Museum, CC BY-SA 4.0

 



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