Random tree and shrub deaths and die back in an urban environment at sites which always show modestly but occasionally drastically elevated radio frequency power densities  compared to background and arising from multiple sources, an experimental study.  By Dr Chris Barnes, Bangor Scientific and Educational Consultants. E-mail doctor.barnes@univ.bangor.ac.uk. 

1st released into internet public domain in Beta form  (without complete reference list) August 21st 2013.

Dr Barnes Homepage http://www.drchrisbarnes.co.uk




A brief definition of tree die back together with classical explanations is given.  More recent explanations cite pollution as a contributing factor.   In an urban environment there is road, industrial  and aviation pollution in addition to Radio Frequency Pollution or electro-smog.  This paper reports on an experimental study in an urban environment, the city of Bangor, Wales which seems to show that when  random tree and shrub deaths and die back happens in an urban environment it happens at sites which always show modestly but occasionally drastically elevated radio frequency power densities  compared to background given that the RF is arising from multiple sources.    It is theorised that trees act as antennas because there component parts form multi-frequency   dielectric resonators.  If vegetation has adsorbed or absorbed large amounts of conductive or magnetically susceptible pollutant nano-material these resonances may be shifted and the vegetation may even become a parasitic re-radiator of RF energy.       Further work is necessary to establish if RF at these power densities can ever be herbicidal in its own right or if it merely acts to potentiate other stresses such as the effects of pollutants, diseases and/or predators.   Nothing in the work   contradicts the quantum mechanical model for predicting  bio-damage previously advanced by the author.   




Tree die-back is not a brand new phenomenon and reported cases go back to the 1950's. 

Indeed had not whole forests died over archaeological timescales  due to natural climatic evolution then modern industrialisation as we know it would not have taken place.



However, what sets modern day die-back as distinct from whole forest decline is  the range of age and species of tree and shrub affected and the fact that apparently healthy, young plants  will quite suddenly appear to falter and wither from their growing shoot and leaf tips stem downwards.



It is true that a number of diseases and predators have in recent years been identified and account for species specific  dieback particularly of oak, elm and ash.



The present author has noticed, however, that many other kinds of almost random species of trees and shrubs appear to be suffering demise. The question which arises is are there other sorts of stress factors affecting or altering the biological growth processes of this vegetation or making it more susceptible to attack.   



Atmospheric pollution, particularly aerosol metallic nano-particles have been shown to play a part in tree die-back, see for example but not limited to  Acquaviva et al (2012)[1], Maher (2007)[2].    Moreover, I have recently published evidence of strong support for this hypothesis by showing that tree dieback is often exaggerated close to  high voltage power lines, known to concentrate such pollution.     


Other studies (Silk Personal Communication) and Silk A. Forestry Commission Report (2004) found at [3]   have shown that radio frequency radiation particularly at specific points in antenna radiation beam patterns also accentuates oak die back.    



I   have developed a quantum mechanical model to predict specific radial (quantised) distances from antennas (  treated as isotropic radiators for simplicity)   at which there is maximum bio effect on biological systems in general [4].  From preliminary studies it would appear that the model fits with observation for tree death and die-back.   An important facet of the model is that damage is done only by the modulation in a radio-frequency signal the information being contained in the magnetic vector potential which is not readily screened or attenuated.    Thus the model would tend to predict that there may be damage at even at low field strengths.


I have  further theorised on  adsorbed and absorbed  nano-metal particles  facilitating plant leaves to become radio antennas, thereby further maximising radio frequency absorption.      Generally there are more such particles available in an urban environment, particularly with heavy   traffic flow.   I live in a city not only with very heavy traffic flows but also over-flown by  major west-east air routes so there is further potential provision of conductive  or magnetically susceptive nano-particles here.   



Experimental  and Apparatus

The apparatus used was a  Cornet Microsystems  field meter, type ED75.  

Three simple experiments were performed. Firstly, the RF Power Density inside the author's house was measured in a number of locations adjacent to house plants and shrubs.


Secondly, the power density was measured in the author's garden generally and adjacent to any plants/shrubs which showed signs growing tip dieback. There were no completely dead plants in the garden.         


Finally, the author walked a circular route for approximately two miles keeping his house as a point on the circumference of the circle.    The route took in other urban roadways abutting gardens, an urban farm and an urban area of woodland.  Background power densities were measured as were those immediately adjacent to or as close as practically possible to any dead and dying tree or shrub vegetation including, for example, trees   with shoot tip die back or larger trees with complete dead branches or dead sections and including completely dead trees.  


In each of the three experiments also noted was the type of any nearby line off site or visible mobile phone, radio or TV transmitter mast.   


Results :


Experiment 1

Inside the house the E-Field varied from 0.7-1.4 microwatts cm^2.   There were no dead house plants or shrubs and none with any tip die-back.  There are multiple possible radio-frequency sources  the strongest including WIFI 2400 MHz , GSM 900 MHz, 3G 1800 MHz , TETRA 390 MHz , Paging 153 and 137 MHz.  There are no plants or people in the room which contains the WIFI hub and field strengths immediately adjacent to this are considerably larger. 


Experiment 2

In the garden the background power density was on average about 3 microwatts cm^2. It is envisioned that the sources were the same as above but the power contribution due to WIFI would be less.  


Slight growing tip die back was evident on a number of trees and shrubs including; a peach tree, an Acer and a winter flowering cherry adjacent to all of these power densities  in the region of  6 microwatts cm^2 were measured.  It should be noted that although these fields are higher the average background they are still relatively modest compared with those cited for public exposure limits in certain countries, see    http://www.hese-project.org/hese-uk/en/niemr/power_density_effects.pdf     [5].



Experiment 3


The highest power density of 500 microwatts cm^2  measured in this experiment was adjacent to a dying shrub in a garden some 300 metres away to the South West from the author's residence.  The most visible antenna mast was TETRA about 1000 metres away and line of site but additionally the site was only about 150 metres away from a multi- frequency  site employing GSM 900, 3G and 153 MHz paging.  Disturbingly, this level of field was very close to a residential property and approaches the FCC limit  which is regarded by some as very high) and exceeded the ICNIRP 6 minute guidance limit. 


Perhaps the most interesting results were found in the urban woodland.  This was an area of woodland in the shadow of a hill which shielded the TETRA signals but there was line of site with other sources including GSM 900, 3G 1800, VHF FM radio, VHF  DAB and UHF DVB. However, the latter three were some 5 km distant.  


Typically the average field strengths were quite low of the order of 1 microwatt cm^2 but without fail were always well elevated over this value in the region of dead and dying vegetation, surprisingly so even at heights of  only a metre or so above the ground.       Intriguing was in some cases how the power density peaked by up to two orders of magnitude when the field meter was brought into almost close contact with the dying vegetation.   The hypothesis is that trees can act as antennas although this is by no means new, see for example but not limited to  Ikrath et al (1972) [6].  The question arising here however perhaps relates to elucidating if dead and dying trees make better antennas especially at VHF, UHF and microwave frequencies.  This notion will be discussed later.



Conclusions, Discussion and further work.   

The above study has shown that in urban outdoor locations where trees and shrubs of various species are showing death or die back there is always an elevated RF power density compared with the average background.  Such at first site apparently random tree and shrub deaths and die back in an urban environment is at sites which always show modestly but occasionally drastically elevated radio frequency power densities  compared to background and is where the RF energy could be arising from multiple sources. No indoor plants or shrubs appear to have been affected in a similar way although the power densities in involved were somewhat lower.


The hypothesis supported is that pollution, most probably metallic nano-particles, and RF energy are required to maximise certainty of tree and shrub damage. Such damage can occur at surprisingly   low power densities and supports the notion that we should always err on the side of caution where radio frequency exposure of biological systems is involved.


It is logical to suppose that trees and shrubs can act as dielectric resonators. I propose that   the very distinct sections of trees such as leaves, twigs and branches allowing for multiple frequency resonance and hence making trees and shrubs very good receiving antennas.  The notion that a tree can indeed be used as a receiving antenna is not new ,see Squier [7].   The resonance frequencies are together with the aerial efficiency  presumably modified  by the incorporation of    nano-metallic pollutants which are both conductive and magnetically susceptive, thereby ‘tuning’ the leaves etc. to resonance.   This is borne out by the observation of a sharp rise in measured power density in very close to even dying vegetation and even at close to ground level.   The notion  of multiple resonance  effects would simply imply then on balance the more RF Sources in the environment  the more likely are trees and shrubs to succumb  to coincident stresses such as pollution and/or  disease.    


The greater majority of modern RF sources are either pulsed emissions or emissions with at least some component of amplitude modulation or variation.   Publications far too numerous than to cite here   stress the dangers of such emissions to humans.  Other publications claim there is no or little harm to public health of non -thermal radio frequency radiation.  Deleterious  Bio effects would, however, seem to be taking place in vegetation allied to such emissions, this and the  fact that such effects take place at relatively low power densities is not in contradiction  with the author's quantum mechanical hypothesis.     The fact that in the real environment multiple RF pollution is present does make exact prediction of sites where bio-damage will occur  more difficult. 


Nothing in this work suggests that RF alone is responsible for tree death  only that either it is a compounding factor.  Alternatively, sceptics might argue that  potentially in some cases that background power levels are simply 'tuned up' by pieces of nanao-particle infested dying vegetation acting as parasitic ( re-radiating) antenna systems.  Others have very recently confirmed my hypothesis regarding leaf adsorption of nano-particles, see Richard (2013)[8].   However, others have in the past argued for RF as an exclusive herbicide.  Species as diverse as pine (needles) [9], tomatoes (Roux et al 2006)[10]  and duckweed (Tkalec et al 2007) [11]have been considered.     For the latter, oxidative stress was identified as the mechanism. I too have considered the same in an attempt to link bio damage effects of RF in both plants and animals, see http://www.drchrisbarnes.co.uk/Unified.htm[12].



Doubtless further work either of this or other interested authors will eventually clarify the situation.  One possible suggested study is to move pollution free  indoor houseplants and shrubs into close proximity with a WIFI hub and observe the outcome.   Another possible study would be to  place small healthy urban  garden  shrubs, which may have been exposed to atmospheric pollution but not appropriate RF fields,  into household planters, to bring them indoors and place adjacent to a similar WIFI hub.     The outcome of such studies would presumably clear up the possible ambiguity highlighted above. 


References ( added February 2015)


1.      http://link.springer.com/article/10.1007/s11356-012-1030-x#page-1

2.      http://www.sciencedirect.com/science/article/pii/S1352231007008175

3.      http://www.hese-project.org/hese-uk/en/issues/nature.php?id=trees

4.      UK Patent Application GB 1113174.5 A method and apparatus for more accurate prediction of locations in the vicinity of transmitting antennas or base stations wherein occupants or other life forms face maximum deleterious bio-effect.

5.      http://www.hese-project.org/hese-uk/en/niemr/power_density_effects.pdf    

6.       http://dtic.mil/dtic/tr/fulltext/u2/742230.pdf

7.      http://www.rexresearch.com/squier/squier.htm

8.      http://www.treehugger.com/natural-sciences/trees-are-awesome-study-shows-tree-leaves-can-capture-50-particulate-matter-pollution.html

9.      Premature aging of pine needles at power density of 0.000027 µW/cm2 (Selga T, Selga M (1996), ‘Response of Pinus sylvestris L. needles to electromagnetic fields. Cytological and ultrastructural aspects’, The Science of the Total Environment Vol. 180, pp. 65-73, Elsevier Science BV)

10.  http://www.researchgate.net/publication/229659230_Electromagnetic_fields_%28900_MHz%29_evoke_consistent_molecular_responses_in_tomato_plants

11.  http://www.sciencedirect.com/science/article/pii/S0048969707008017

12.  http://www.drchrisbarnes.co.uk/Unified.htm