The outer skin of a tree trunk, outside the secondary, vascular, cambium. It is composed of phloem tissues, which occur as living inner and dead outer zones. The outer zone is penetrated by the cork layers (or periderms) formed from cork cambia (or phelloderms), and is sometimes called the rhytidome. The bark surface is variously sculptured, e.g. smooth, scaly, or fissured; and these surface features are partly determined by the arrangement of the phloem tissues and periderms.
Subjects: Plant Sciences and Forestry.