Forest Chemistry
The volatile chemical substances released into the air by forest trees and plants are called phytoncides. The primary substances are a-pinene and isoprene and, more specifically, the terpenoids C10 to C15 monoterpenes, sesquiterpenes and C5 hemiterpenes. The amounts released by the various parts of the trees vary during the daytime and during the seasons. The amounts tend to collect near the centre of a forest and close to the ground. It is claimed that phytoncides act as insect
repellents, anti-microbal, antiseptic and possibly analgesic agents (to wit,
aspirin is found white birch bark) and inhibitors of other plants’ growth.
Phytoncides are claimed to exert a refreshing effect on humans, for instance
via tree essential oils, notably frankincense. Japanese
research has shown that the amounts of volatile substances in the forest air
are too small to have any direct chemical impact on human health. The effect
of tree aroma on humans, specifically its placebo effect, has not been
ascertained save by dodgy (because mightily biased) aroma therapy
researchers. It is likely
that the placebo effects (to wit, benign mental mis-directions) of olfactory,
visual and auditory flooding of the brain, and which produces an intense
positively experienced altered state, produce the beneficial affects of
forest bathing so often (subjectively) reported, even from ancient times. For more
detail see: ‘Forest
Bathing’, Ed. Qing Li (2013) ‘Die sanfte
Medizin der Bäume’, Moser & Thoma (2014) |