Tree bark: a multifunctional tissue

https://asknature.org/strategy/quorum-determines-new-hive-site/

https://en.m.wikipedia.org/wiki/Bark_(botany)

Sharp spines on a giant palm tree, Malaysia

Slough off or peel away

Rainbow eucalyptus bark (Eucalyptus deglupta)

Living on bark

Pine tree bark with moss and lichen, Galicia, Spain

Lichens are a symbiotic association of a fungus (Fungi) with either a green alga (Protoctista) and/or a cyanobacterium (Monera). All living together for their mutual benefit!

Lichens are epiphytes and take nothing from the tree that they are growing on, other than a place to live and thrive. The algae and / or bacteria do the job of photosynthesising, whilst the fungus provides support and protection. What’s not to love about them?!

Yellow Xanthoria lichen on an English woodland tree. This lichen thrives in nitrogen-rich environments

Lichens obtain water and minerals from rain and dust particles in the atmosphere, which means that they are sensitive bioindicators of air quality, and they respond directly to the ambient conditions, including pollution.

Multicoloured flora on lichens, moss and algae

Living under bark

A huge variety of creatures live under bark, most notably wood-boring beetles, but many others use it for protection and over-wintering, particularly in fallen trees and branches.