BBE 1001 Lecture Notes - Lecture 10: Dendrochronology, Specific Gravity, Cubic Foot
16 Dec 2017
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Abnormal wood - characteristics of parts of a tree. Forms underside of a leaning stem to push tree up. At a swollen state, large s2 microfibril angle cause large cell expansion on underside of the leaning portion to push tree into vertical position. Forms on top of leaning stem to pull tree up. S2 layer may not be present at all. Almost pure cellulose, loosely attached to s1 layer. When it loses bound out, tension wood shrinks in length due to lack of a functional s2 layer. When at swollen state, gelatinous layer causes cell to expand in width. Large lateral expansion of cells causes axial shrinkage on upper side of leaning portion to pull tree into vertical position. The younger the tree the more juvenile wood. Heartwood is related to death of cells, so heartwood would be much smaller than older wood. Tip of branches and base of tree center will always be juvenile wood.
