The networked tree

Installing the sap-flow gauge on the Twitter tree.

Installing the sap-flow gauge on the Twitter tree. / Photo: Spektrum der Wissenschaft / Richard Zinken

An oak in the Botanic Gardens of FAU brings together science, technology and nature

A 150-year-old oak tree in Erlangen has been given a “voice”. It has been equipped with cutting-edge measuring equipment to report on its existence – whilst supplying data for the “Bäume in Klimawandel” [Trees under climate change] research project. The “Talking Tree” is a cooperative project between the Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) Botanic Gardens and Institute for Geography and Spektrum der Wissenschaft [Scientific Spectrum] magazine; it is sponsored by Siemens.

At the core of the “tweeting tree” is the oak’s black box, as it were. It collates the environmental influences recorded on the devices and sends the information to a central computer. Data is, in part, provided by a weather station, which has also been fitted to the oak, to measure wind speed, temperature and rainfall at the location. The tree’s reaction to such influences is monitored by two additional technologically sophisticated sensors. A gauge to measure sap flow continuously registers how much water is absorbed from the earth and transported to the leaves whilst a dendrometer measures annual tree growth through photosynthesis; recording any increase in the tree’s diameter. Furthermore, environmental data relating to particle dust and ozone levels is sent from a measuring station belonging to the Bavarian Environment Agency to the Twitter tree’s central computer. It collates and evaluates all the measurements and, with the help of specialist software, transforms them into short text messages. The oak is then able to report that, for example, an icy wind is tugging at its boughs, it is ready to bloom or that ground-level ozone is damaging its leaves and impairing photosynthesis – all online via its website and Twitter page. What’s more, a camera makes it possible for any visitor to the website to check up on how the tree is changing over the course of the year.

But all this effort is not just an entertaining means of combining ecology and new media – it has genuine scientific worth. The collated data is to be evaluated by the Institute for Geography in Erlangen and fed into various research projects – all relating to the topic of “urban climate and urban vegetation”. Erlangen scientists connected to the Chair of Physical Geography (Prof. Dr. Achim Bräuning) are also involved in a project with the Bavarian research network FORKAST to research the effect of extreme climatic events on oak and beech forests in arid locations. The researchers are investigating questions such as: When and how does a tree actually grow? How does a tree in the city differ from one in a forest? Does it suffer as a result of dryness and pollutants in summer and does this affect growth at all? Can conclusions be drawn from this, as to how forest trees will react in future if climate change results in hotter, longer summers and, as such, increasingly mirrors today’s urban climate? Much of this can be extrapolated from the Twitter tree already – even now, as it serves as a kind of online ambassador for its fellow trees of the forest.

The forerunner of the Erlangen tree is a beech tree in Brussels, although it was not used for scientific purposes. New York is, however, also set to have its own Twitter tree.

Representatives of the media are warmly invited to the following event:
Susanne Klarmann from the FAU Institute for Geography and project leaders Richard Zinken and Dr. Daniel Lingenhöhl from Spektrum der Wissenschaft shall be presenting the research project on Friday 9 September at 2pm in the Botanic Gardens (next to the administration building).

Further information:
Prof. Dr. Achim Bräuning
Tel.: 09131/85-29372

Dr. Daniel Lingenhöhl
Tel.: 06221/9126815

uni | media service | research No. 40/2011 vom 1.9.2011