Hibernation

Deciduous trees have been around for about 100 million years but conifers are 170 million years older – so perhaps it’s no surprise they hibernate differently.

Most deciduous trees photosynthesise for as long as possible. They transport energy from leaves to trunk and roots while breaking down chlorophyll into its component parts for future use (leaves).

Shedding leaves (abscission) is a survival measure, preventing the take-on of extra weight in snow and ice and reducing wind resistance. Most species also start reducing their water content from summer, as hard frost can otherwise cause serious damage, much like water pipes.

Wild and bird cherries are deciduous trees that begin hibernation early, reddening in late summer. As small trees, their tissue fills with food and they run out of storage space.

Alders shed their leaves while still green, as do oaks and beeches to a lesser extent. They get away with it because they thrive in wet conditions and produce chlorophyll every year.

Conifers take a different approach, keeping their tough needles (leaves) which form a thick protective layer of wax with breathing holes buried deep in the underside. They would die of thirst otherwise, unable to replace water from frozen ground.

Larch, dawn redwood and bald cypress are the only species of conifer to shed their leaves.

Both deciduous trees and evergreens suffer sleep deprivation just like humans – which is why they won’t survive indoors in a container.

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Image: mbll (Pixabay)