Eucalyptus

Eucalyptus tree (Eucalyptus spp.)

Description

Eucalyptus (Eucalyptus spp.)

Over 700 evergreen tree species belong to the genus Eucalyptus. They are native to Australia but are now grown in many subtropical locations around the world (California, Spain, South America, India, South Africa, etc.). Eucalyptus wood is used for construction, papermaking pulp, inexpensive furniture and small turned items such as paintbrush handles. Most eucalyptus wood is durable but not dimensionally stable. The bark from the trees, however, is high in tannins and is used on a large scale for leather production. Most commonly used tannins are obtained from Maletto bark (E. astringens) and mugga or Red iron bark (E. sideroxylon). These tend to produce a dark red leather and are sometimes mixed with other tannins. Eucalyptus oil is obtained from the dry leaves of several species of eucalyptus trees especially E. salicifolia and E. globulus (blue gum).

Synonyms and Related Terms

gumwood; white mountain ash; eucalyptus (Fr., Sven.); Eukalyptus (Deut.); eucalipto (It.); eucalipto (Esp., Port.); eucalyptusboom (Ned.); eukaliptus (Pol.); Tasmanian oak (Eucalyptus regnans); blue gum (Eucalyptus globulus); red iron bark (Eucalyptus sideroxylon); maletto bark (Eucalyptus astringens)

Physical and Chemical Properties

• Color: light brown.
• Rings: distinct.
• Pores: distinct, coarse.
• Grain: distinct.
• Rays: obscure.
• Hard, heavy wood.
• Density = 42 ppcf
• Specific gravity = 0.67

Paper fiber type: Hardwood. Using transmitted light microscopy, fibers are short and thin, with some pitted tracheid fibers. Large, oblong vessel elements with long tails are present. Vessels have oval to round ray parenchyma pits in horizontal rows. Vasocentric trachieds are also present. Appearance with Graff "C" stain: varies with bleaching. Average dimensions of fibers: length 1.1mm, width 20μm. Common pulping method: kraft.

Additional Images

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  Blue gum (Eucalyptus globulus); tangential cross-section at 100x

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  Blue gum (Eucalyptus globulus); radial cross-section at 100x

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  Blue gum (Eucalyptus globulus); transverse cross-section at 100x

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  Eucalyptus pulp stained with Graff "C" Stain

Resources and Citations

• G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 382

• Matt Roberts, Don Etherington, Bookbinding and the Conservation of Books: a Dictionary of Descriptive Terminology, U.S. Government Printing Office, Washington DC, 1982

• The Dictionary of Paper, American Paper Institute, New York, Fourth Edition, 1980

• E.J.LaBarre, Dictionary and Encyclopedia of Paper and Paper-making, Swets & Zeitlinger, Amsterdam, 1969

• Encyclopedia Britannica, http://www.britannica.com Comment: "Eucalyptus." EAccessed 7 Apr. 2005 .

• H.L.Edlin, What Wood is That?, Viking Press, New York, 1969

• Wikipedia: http://en.wikipedia.org/wiki/Eucalyptus (Accessed Dec. 9, 2005)

• Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976

• Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997

• Marja-Sisko Ilvessalo-Pfäffli. Fiber Atlas: Identification of Papermaking Fibers (Springer Series in Wood Science). Springer, 1995.

• Walter Rantanen. "Fiber ID Course." Integrated Paper Services. June 2013. Lecture.