What's killing your plants?

London: As if our magnificent trees didn't have enough problems, they're now being threatened by our e-mails.

When they're not being assailed by some foreign bug or moth, there's often a council official looking for excuse to cut them down.

Now researchers say radiation from wi-fi networks that enable our burgeoning online communications may be their latest enemy.

Trees planted close to a wireless router had bleeding bark and dying leaves, according to the study in Holland.

The revelation will raise fears that wi-fi radiation may also be having an effect on the human body and supports parents who have campaigned to stop wireless routers being installed in schools.

The city of Alphen aan den Rijn, in the Netherlands, ordered the study after officials found unexplained abnormalities on trees.

Researchers took 20 ash trees and for three months exposed them to six sources of radiation. Trees placed closest to the wi-fi source developed a "lead-like shine" on their leaves that was caused by the upper and lower epidermis — the leaf's skin — dying. Researchers also discovered that wi-fi radiation could slow the growth of corn cobs.

Unaffected

In the Netherlands, 70 per cent of all trees in urban areas show the same symptoms, compared with 10 per cent five years ago, the study found. Trees in densely forested areas are not affected.

The Wageningen University scientists behind the research, which has not yet been published, said that further studies were needed to confirm their findings.