Trunk
/trʌŋk/
Definition
Trunk refers to the main woody stem of a tree, palm, or other tree-like plant. It forms the central upright axis, supporting the crown and conducting water, minerals, and sugars between roots and leaves through vascular tissues. Unlike smaller branches or multiple stems arising near the base, a trunk is the primary, usually thickened stem, often covered with bark in woody species and marked by secondary growth in many trees.
Function in Plants
- Support for the crown: In woody plants, the trunk holds branches and leaves high enough to capture light and resist bending from wind, snow, and fruit load.
- Pathway for water and sugars: Inside the trunk, xylem moves water and minerals upward, while phloem carries sugars and other products of photosynthesis to roots, shoots, and developing tissues.
- Storage and long-term growth: The trunk can store water and carbohydrates, helping a plant cope with stress and seasonal change. Its thickening comes from the vascular cambium, a growth layer that produces new wood and inner bark.
- Clue to age and condition: Bark pattern, trunk form, wounds, and decay can reveal species traits, past pruning, environmental stress, or structural weakness, so this part is important in tree assessment and garden care.
Related Terms
Xylem
Xylem is the plant vascular tissue that carries water and dissolved minerals from the roots to stems and leaves. It…
Vascular tissue
Vascular tissue is the plant transport system, made of xylem and phloem. Xylem carries water and dissolved minerals…
Woody plant
Woody plant refers to a plant that produces persistent woody stems or trunks through secondary growth, the thickening…