Trunk (botany)
In botany
Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...

, trunk (or bole) refers to the main wooden axis of a tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...

 that supports the branch
A branch or tree branch is a woody structural member connected to but not part of the central trunk of a tree...

es and is supported by and directly attached to the root
In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. This is not always the case, however, since a root can also be aerial or aerating . Furthermore, a stem normally occurring below ground is not exceptional either...

s. The trunk is covered by the bark
Bark is the outermost layers of stems and roots of woody plants. Plants with bark include trees, woody vines and shrubs. Bark refers to all the tissues outside of the vascular cambium and is a nontechnical term. It overlays the wood and consists of the inner bark and the outer bark. The inner...

, which is an important diagnostic feature in tree identification, and which often differs markedly from the bottom of the trunk to the top, depending on the species. The trunk is the most important part of the tree for timber
Timber may refer to:* Timber, a term common in the United Kingdom and Australia for wood materials * Timber, Oregon, an unincorporated community in the U.S...

 production. Trunks occur both in "true" woody plants as well as non-woody plants such as palms and other monocots
Monocotyledons, also known as monocots, are one of two major groups of flowering plants that are traditionally recognized, the other being dicotyledons, or dicots. Monocot seedlings typically have one cotyledon , in contrast to the two cotyledons typical of dicots...

 though the internal physiology is different in each case. In all plants, trunks thicken over time due to formation of secondary growth (pseudo-secondary growth in monocots).

Trunks can be vulnerable to damage, including sunburn
A sunburn is a burn to living tissue, such as skin, which is produced by overexposure to ultraviolet radiation, commonly from the sun's rays. Usual mild symptoms in humans and other animals include red or reddish skin that is hot to the touch, general fatigue, and mild dizziness. An excess of UV...


External links

  • Inside a tree trunk from University of the Western Cape
    University of the Western Cape
    The University of the Western Cape is a public university located in the Bellville suburb of Cape Town, South Africa. It was established in 1960 by the South African government as a university for Coloured people only...

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