Discovery that trees give off ELECTRICITY creates a buzz
- Levels of charged ions twice as high in wooded areas
- Deep-rooted trees such as eucalyptus even higher
- Effect created by trees 'channelling' radiocative radon gas from soil
- Not thought to be harmful to health on its own
By Rob Waugh
Scientists in Australia found the area round trees was filled with charged particles - ions - both positive and negative.
Levels were twice as high in wooded areas as they are in open, grassy areas, and deep-rooted trees such as eucalyptus were even higher.
A eucalyptus forest in Heidelberg, South Africa: Scientists believe that all trees give off electricity - but the effect is particularly powerful with deep rooted trees such as eucalyptus
The researchers from Queensland University of Technology don't believe that the ions are in themselves harmful to health.
Researchers have long believed there is a link between trees and electricity in the atmosphere but have been unable to prove the association.
But scientists from the Queensland Univeristy of Technology have shown that concentrations of negative and positive ions in the atmosphere were twice as heavy in wooded area as in grassy regions.
Dr Rohan Jayaratne said the charges could be explained by radiation from the gas radon.
Radon is a by-product of the radioactive decay of radium, which is exhaled by the ground.
Trees acts as pumps, bringing the gas to the surface and releasing it, said Dr Jayaratne.
He said: ‘Because radium is found in rocks and radon is soluble in water, ground water is particularly rich in radon.
‘Trees act as radon pumps, bringing the gas to the surface and releasing it to the atmosphere through transpiration - a process where water absorbed by the root system is evaporated into the atmosphere from leaves.
‘This is especially prevalent for trees with deep root systems, such as eucalyptus.’
Writing in the journal Environmental Science and Technology, they estimate that in a eucalyptus forest trees may account for up to 37 per cent of the radon in the air when transpiration rates were highest.
The charged ions could have health implications although they are not believed to be harmful on their own, he said.
He explained: ‘Although there is an established link between airborne particles and human health, the role of ions is largely unknown.
‘However, we do know that approximately one-half of the particles that we inhale during normal breathing are retained in our respiratory system and it has been shown that charged particles were more likely to be deposited in the lungs than uncharged particles.
‘We do not believe that ions are dangerous - the danger comes from the pollutants. If there are no dangerous particles in the air to attach to the ions there is no risk of ill health.’
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