Observations placeholder

Watson, Lyall - Willows and alders warn each other when they are being attacked



Type of Spiritual Experience


Activity dependency chemical signals trigger plant action.

The question here is not the communication which may well be a chemical signal, but how a chemical signal can be converted into action in the form of an alkaloid defence.  Trees do not have brains, so where is this intelligent action coming from?

A description of the experience

Lyall Watson – Heaven’s Breath

Botanists working in woods near Seattle have just discovered that willows and alders warn each other when they are being attacked by leaf eating insects.  The natural defence of these plants to attacks by tent caterpillars or webworm is to produce alkaloids in their leaves that make them unpalatable.  And when a tree is infected it sends out an airborne warning cry in the form of a chemical, probably one of the terpenes, that starts other trees some distance away preparing to meet the onslaught.  Sugar maple and poplar saplings do something similar when mechanically damaged by having their leaves plucked or torn.

The source of the experience

Watson, Lyall

Concepts, symbols and science items


Science Items

Activities and commonsteps