Forest and Shade Tree Pathology

Wood Chemistry and Anatomy

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**Wood chemistry**
Component	Approximate composition by weight	Structure
Cellulose	50%	linear chains of glucose (beta-bond)
Hemicellulose	25%	branched chains of various sugars
Lignin	25%

**Cell Types in Wood**
	Softwood (Conifer)	Hardwood (Angiosperm)		Both
Cell Type	Tracheid	Vessel Elements	Fiber	Parenchyma
Function	conduction + support	conduction	support	storage, defense
Shape	long, narrow	short, wide	short, narrow	various
Arrangement	connected with pits	connected end to end into long vessels	connected with narrow pits	Oriented radially in rays and, in hardwoods, longitudinally near vessels

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	Elsewhere: On this server: Wood decay and stem rot Vascular wilts Forest Pathology home page

Last modified 27 May, 2007