Trunk (botany)
The base of a Yellow Birch trunk
In botany, the trunk (or bole) is the stem and main wooden axis of a tree,[1] which is an important 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 production.
Trunks occur both in "true" woody plants as well as non-woody plants such as palms and other monocots, though the internal physiology is different in each case. In all plants, trunks thicken over time due to formation of secondary growth (or in monocots, pseudo-secondary growth). Trunks can be vulnerable to damage, including sunburn. Trunks which are cut down in logging are generally called logs and if cut to a specific length bolts.
Contents
1 Structure of the trunk
2 See also
3 References
4 External links
Structure of the trunk
The trunk consists of five main parts: the bark, inner bark, cambium, sapwood, and heartwood.[2] From the outside of the tree working in, the first layer is the bark; this is the protective outermost layer of the trunk. Under this is the inner bark which is made of the phloem. The phloem is how the tree transports nutrients from the roots to the shoots and vice versa. The next layer is the cambium, a very thin layer of undifferentiated cells that divide to replenish the phloem cells on the outside and the xylem cells to the inside. Directly to the inside of this is the sap wood, or the living xylem cells. These cells transport the water through the tree. Finally at the center of the tree is the heartwood. The heartwood is made up of old xylem cells that have been filled with resins and minerals to keep other organisms from growing and infecting the center of the tree.
Raft of timber logs
Cross section of a hazel bole
Log being decomposed by bracket fungi
See also
- Bark
- Basal area
- Tree measurement
- Tree volume measurement
- Diameter at breast height
References
^ "trunk". The Free Online Dictionary. Retrieved 2017-02-17..mw-parser-output cite.citation{font-style:inherit}.mw-parser-output q{quotes:"""""""'""'"}.mw-parser-output code.cs1-code{color:inherit;background:inherit;border:inherit;padding:inherit}.mw-parser-output .cs1-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/6/65/Lock-green.svg/9px-Lock-green.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-limited a,.mw-parser-output .cs1-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/d/d6/Lock-gray-alt-2.svg/9px-Lock-gray-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/thumb/a/aa/Lock-red-alt-2.svg/9px-Lock-red-alt-2.svg.png")no-repeat;background-position:right .1em center}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration{color:#555}.mw-parser-output .cs1-subscription span,.mw-parser-output .cs1-registration span{border-bottom:1px dotted;cursor:help}.mw-parser-output .cs1-hidden-error{display:none;font-size:100%}.mw-parser-output .cs1-visible-error{font-size:100%}.mw-parser-output .cs1-subscription,.mw-parser-output .cs1-registration,.mw-parser-output .cs1-format{font-size:95%}.mw-parser-output .cs1-kern-left,.mw-parser-output .cs1-kern-wl-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right,.mw-parser-output .cs1-kern-wl-right{padding-right:0.2em}
^ Ward, James. "A Tree and Its Trunk page 2". dendro.cnre.vt.edu. Retrieved 2018-02-08.
External links
 | Wikimedia Commons has media related to Tree trunks. |
Inside a tree trunk from the University of the Western Cape
 | This tree-related article is a stub. You can help Wikipedia by expanding it. |
