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The trunk consists of five main parts: The outer bark, inner bark , cambium, sapwood (live xylem), and heartwood (dead xylem). [2] From the outside of the tree working in: The first layer is the outer bark; this is the protective outermost layer of the trunk. Under this is the inner bark which is called the phloem. The phloem is how the tree ...
Heartwood formation is a genetically programmed process that occurs spontaneously. Some uncertainty exists as to whether the wood dies during heartwood formation, as it can still chemically react to decay organisms, but only once. [13] The term heartwood derives solely from its position and not from any vital importance to the tree. This is ...
Heartwood – the older, nonliving central wood of a tree or woody plant, usually darker and harder than the younger sapwood. Also called duramen. Herbaceous – non-woody and dying to the ground at the end of the growing season.
In woody plants, a tylosis (plural: tyloses) is a bladder-like distension of a parenchyma cell into the lumen of adjacent vessels. The term tylosis summarises the physiological process and the resulting occlusion in the xylem of woody plants as response to injury or as protection from decay in heartwood. [1]
Heartwood (duramen) Pith (medulla) In young stems, which lack what is commonly called bark, the tissues are, from the outside to the inside: Epidermis, which may be replaced by periderm; Cortex; Primary and secondary phloem; Vascular cambium; Secondary and primary xylem.
It transports water and minerals from the roots to the upper parts of the tree. The oldest, inner part of the sapwood is progressively converted into heartwood as new sapwood is formed at the cambium. The conductive cells of the heartwood are blocked in some species. Heartwood is usually darker in colour than the sapwood.
The diseased heartwood softens, making trees structurally weaker and prone to breakage. Heart rot is a major factor in the economics of logging and the natural growth dynamic of many older forests. Heart rot is prevalent throughout the world affecting all hardwood trees and can be very difficult to prevent.
The common English name hornbeam derives from the hardness of the woods (likened to horn) and the Old English beam, "tree" (cognate with Dutch Boom and German Baum).. The American hornbeam is also occasionally known as blue-beech, ironwood, or musclewood, the first from the resemblance of the bark to that of the American beech Fagus grandifolia, the other two from the hardness of the wood and ...