Popular Poplar on Social Media

(June 13th, 2017) Expecting tweets only from birds sitting in trees? A poplar tree at Wageningen University learned to twitter itself – with a little help from the scientists who work with it.

Followers of @TreeWatchWUR are in for quite an unusual encounter – not bots or trolls, but real trees. The tree is a popular and huge poplar tree, standing near a café at the Wageningen Campus in the Netherlands. Every day, it sends out updates on its well-being, impressing followers with how much water it transports in its vessels - about 10 litres a day - or how much it grows - 0.2 mm a day. With this project, the scientists behind the scenes want to raise awareness of tree physiology, behaviour and interactions with the environment.

“Good morning, my sap has just started flowing” could be a typical tweet from the poplar. It is sent out by instruments that measure the sap flow and turn this information into text messages on Twitter. Besides the sap flow meter, which records how fast the tree transports water in its cells, the tree has a dendrometer connected to it. This instrument keeps a sensor on the tree's width, which gets larger as the tree grows but also fluctuates during the day. Combined, these data show how the tree drinks during the night and swells, and how it loses water that evaporates during the day. As a rather modern addition, these measurements are made and reported in real-time on social media.

Next to the poplar is also a climate station and a soil humidity meter, which oversee how wet and warm the air and soil are. “The measurements are being used to get a picture of the tree’s physiological response to environmental factors”, explains project leader Ute Sass-Klaassen. She is proud of the “gadgets” and the posts on Twitter – and the real science behind it.

Sass-Klaassen and colleagues also look into the tree’s past. Poplar trees adapt their growth activity to changing weather conditions, and fingerprint this growth activity in their tree rings - the thicker a ring, the more growth in one year. The twittering poplar tree is only 30 years old, but some of its relatives can live several hundreds years. By observing the tree’s physiological activities in real-time, Ute Sass-Klaasen and her colleagues hope to make predictions about their adaptation to climate changes. “Every tree is an archive. But first you need to find the key that will let you decipher the information”, says Sass-Klaassen in the Wageningen campus’ journal, Resource.

The Wageningen tree is the first of its kind in the Netherlands but it has colleagues elsewhere in Europe: In Belgium an oak, a maple, and a beech tree are twittering about their daily lives, and in Germany, it's a Scots pine. Soon, a larch in Switzerland and another Scots pine in Spain will join the twittering tree family.

The network is part of a European programme named COST STReESS (Studying Tree Responses to extreme Events: a SynthesiS), and was developed by the Belgian researchers Kathy Steppe and Jonas von der Crone from Ghent University. The researchers want to bring all twittering trees together to learn more about their growth, nitrogen fixation, and water transport. The first chattering forest in Europe.

Karin Lauschke

Photos(2): Silvia Bonomo

Last Changes: 07.03.2017