About four years ago scary news about research that had shown devastating effects of Wi-Fi on trees and plants went all over the Internet. This research was done at Wageningen University in the Netherlands and was allegedly supported by Delft University and TNO. De study was commissioned by the Dutch municipality of Alphen aan den Rijn, in particular by Niek van ‘t Wout, head of green space of that city. Goal of the experiment was to find out whether electromagnetic fields (EM-fields) from Wi-Fi routers might have anything to do with the occurence of a mysterious tree disease which had already affected a lot of trees with bark nodules and fissures. As no known biological explanation could be given for this disease Van ‘t Wout came up with the idea that radiation could be part of the problem.
Soon the story was brought back to its proper proportions: it were just preliminary results and the prestigious institutions apart from Wageningen University were not involved at all. And although the experiment found some differences between the trees exposed to Wi-Fi and an unexposed control group, the experiment was quite small and it was not clear whether there was any connection between the found leaf discolourments and the disease of the trees in Alphen aan den Rijn. A bigger and better controlled experiment was announced, but we had to wait some years to hear anything from this again.
Recently the results were presented on the webpage of Alphen aan den Rijn. It mentions three reports of which the most important, in my view at least, is the replication of the previous study in which trees were grown in climate chambers: Rapportage “Effect EM Velden op bomen” by dr. André van Lammeren (Nov. 2013). In some of the climate chambers radiation sources were placed, in the other rooms dummy versions. This time the researchers also used UMTS and DVB-T transmitters. If you read the summary of the report it becomes clear that this time the researchers are far more careful in presenting their conclusions, of which the first is:
During the experimental research period of 5-8 months no damage like bark nodules, fissures or necrosis were found on the used ash trees in the climate chambers with or without EM-fields.
[Translation by me, the report is in Dutch and has not yet been published in an (international) scientific journal.]
So the study itself is of limited importance in unravelling the cause of the tree disease which was the motivation for the experiments. But it is still interesting to see whether EM-fields had any distinguishable effect at all. But if you read the rest of the conclusions you’ll find out that almost all measurements the researchers took (and they took a lot) showed ‘no significant difference’ between the exposed trees and the control group. They only found some differences in the leaves (curling, forming of exudate), which might be worth further investigation. But I doubt that these small differences should be called significant as no correction was performed for the many outcome measurements that were compared.
Another mentioned report from Wageningen University (F. van Kuik, March 2013) is about a field test. Two groups of trees were planted and surveyed during 1.5 years. One group exposed to Wi-Fi and the other group was planted in an area with low exposure to radiation. Also here there were no real significant differences. But also the researchers stress that they didn’t pay much attention to be sure that other factors (soil and light conditions) were exactly the same between the groups. To me it seems that this experiment was more about checking whether the used tools for measuerements were capable of doing such research for follow up experiments under better controlled settings.
The last report is by Van ‘t Wout himself together with a certain H.Luik (about whom I didn’t found anything). It’s on bio-potentials and inspired by the ideas of Andrew Goldsworthy, a researcher whose name regularly pops up as someone who warns for non-thermal effects of EM-fields. He worked as a scientist, but much of his research I saw is rather dodgy (especially his experiments on ‘magnetically treated’ water) and that makes it difficult to take his ideas very serious (which are not really very wel worked out in any case, much speculation). The experiments for this reports were done at the same time and in the same climate chambers as the other experiments of Wageningen University, but that’s all there is of a connection. The researchers of Wageningen University bear no scientific responsibility for these experiments as was confirmed to me by Van Lammeren. Anyway, to me it seems that the experiments at best show that you can measure with two electrodes stuck in a tree when a transmitter nearby has been put on or off. Even if this proves to be a reliable detection, it remains the question whether this has any meaning for the health of the tree.
To cut things short: the scientific experiments by Wageningen University don’t show any clue that Wi-Fi (or other sources of EM-fields, like UMTS and DVB-T) might have a negative health effect on trees. It therefore is very unlikely that EM-fields play any role in the occurence of the tree disease and the cause of that should be sought in another direction.
You would expect that this result was welcomed by Alphen aan den Rijn, but that doesn’t seem to be the case if you read their website.There the ‘significant’ differences mentioned in the reports are put forward, as well as the perhaps not so scientifically reliable experiments by Van ‘t Wout himself. The website is definitely suggesting there is now proof that Wi-Fi does have an effect on trees. This looks more and more like a personal motivated mission by Van ‘t Wout in which an objective evaluation of the scientific evidence has been lost out of sight. A bit weird that Alphen aan den Rijn gives him so much space to influence the presentation of the results, but he is even more outspoken on Twitter.
Stories about possible negative effects of electromagnetic fields from Wi-Fi, mobile phones and microwave ovens, are picked up quickly and are bound to go viral on the Internet. No matter the quality of the research nor the reliability of the source. We have seen this before with the Danish schoolgirls experiment with garden cress. Note that Van ‘t Wout and Goldworthy were among the foreign ‘experts’ who were so enthusiastic about that experiment.
[Based on my post on Kloptdatwel: Universiteit Wageningen: geen aanwijzingen dat Wi-Fi schadelijk is voor bomen]