Tree tissue. It protects the trunk against the elements, disease, animal attack and fire. It is perforated by a large number of fine breathing pores called lenticels, through which oxygen diffuses. Bark is continually replaced by a living layer of cells called the cork cambium or phellogen. The London plane ("Platanus × acerifolia") periodically sheds its bark in large flakes. Similarly, the bark of the silver birch ("Betula pendula") peels off in strips. As the tree's girth expands, newer layers of bark are larger in circumference, and the older layers develop fissures in many species. In some trees such as the
Eucalyptus redunca Eucalyptus redunca Eucalyptus redunca, commonly known as black marlock, black-barked marlock, wandoo or myrtan, is a tree species in the genus "Eucalyptus" that is native to Western Australia. "E. redunca" produces a tannin of the condensed type. The mallee tree typically grows to a height of but can reach as high as . It has smooth bark and a lignotuber. It blooms between July and November producing yellow flowers. The bark is smooth and a light light brown colour that becomes grey or dark grey brown and peels off in ribbons. The tree has a well-rounded canopy and is one