Lignin
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Lignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in
In pulp mills (like this one in Blankenstein, Germany) using the kraft or the sulfite process, lignin is removed from lignocellulose to yield pulp for papermaking.
Wood
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Wood is a structural tissue/material found as xylem in the stems and roots of trees and other woody plants. Being a natural material, it is characterized as an organic material – a natural composite o
Lignin
…form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot easily. Chemically, lignins are polymers made by the cross-linking of phenolic precursors. Lignin…
A knot on a tree trunk
Wood knot in vertical section
A section of a yew branch showing 27 annual growth rings, pale sapwood, dark heartwood, and pith (center dark spot). The dark radial lines are small knots.
Cross-section of an oak log showing growth rings