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At this time of year, trees are enter into their leaf expansion phase - a process that demands substantial physiological resources, including water.

“That experience was quite interesting because I had never had a physiological feeling like that before.”

Such decay was "not a disease and not a cause for concern" but "a normal, healthy kind of part of the trees' physiological development", said Dr Pyne.

A firm, stable touch on your chest or shoulder can create physiological calm.

For their investigations, the researchers combined physiological studies - such as imaging techniques to visualise processes in the fly brain, chemical analyses of environmental odours, and behavioural studies.