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 sessilis Ranges and Walter James Range in Western Australia. It is also scattered through the Finke River basin, Great Sandy Desert and Burt Plains. Eucalyptus sessilis Eucalyptus sessilis, commonly known as Finke River mallee or river mallee, is a mallee tree that is native to the Northern Territory and central areas along the border of Western Australia. The tree has a spreading and straggly habit, is typically in height, and occurs on stony slopes. Its bark is smooth and peels away in strips when shed. The flowering period is between April to July, the stamens that appear from the capsule are