Difference between revisions of "Softwood"

Latest revision as of 12:31, 12 October 2020

Mechanical softwood

Description

One of two common classifications for trees, Hardwood (angiosperm) and softwood (gymnosperm). Softwoods are coniferous trees. With the exception of the larch and cypress trees, softwoods do not shed their needle-like leaves. Examples of softwood trees are: Pine, Fir, Hemlock, Spruce, Tamarack, Cedar, and Redwood. Softwood trees are found in temperate and mountainous regions. Most of softwoods are used for general construction, fences, and paper pulp. Softwood trees tend to have less acetic acid (1-2%) than hardwoods (3-5%) (Hatchfield 2002).

Chemical softwood (coniferous)

Synonyms and Related Terms

nanboku (Jap.); bois tendre (Fr.); legno di conifera (It.); evergreen; coniferous

Physical and Chemical Properties

Contain tracheids rather than pores. May contain resin channels.

Paper fiber type: Softwood. Using transmitted light microscopy, softwood fibers are identified by the presence of intertrachied "bordered" pits and species specific features such as ray parenchyma pits, size, width, etc. Appearance with Graff "C" stain: sulfite= warm pink to grey, appearance gets lighter with progressive bleaching, kraft=grey blue to purple, appearance gets lighter with progressive bleaching. Average dimensions of fibers: species dependent (average= 3-3.6mm). Common pulping method: kraft and sulfite. The long fibers of softwood pulp impart strength to paper and are often used in conjunction with Hardwood and Rag pulps. Softwood can be pulped mechanically or chemically.

Additional Images

Softwood bleached sulfite paper pulp stained with Graff "C" stain
Softwood unbleached kraft paper pulp stained with Graff "C" stain
Softwood groundwood paper pulp stained with Graff "C" stain
Softwood bleached alpha paper pulp stained with Graff "C" stain
Example of pitting in softwood fibers stained with Graff "C" stain
Red pine paper pulp stained with Graff "C" stain
Sugar paper pulp stained with Graff "C" stain
Larch paper pulp stained with Graff "C" stain
Douglas fir paper pulp stained with Graff "C" stain
Spruce paper pulp stained with Graff "C" stain

Resources and Citations

Alden Identification Services, Microscopic Wood Identification: Link
G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 875

Ralph Mayer, A Dictionary of Art Terms and Techniques, Harper and Row Publishers, New York, 1969 (also 1945 printing)

Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993

Pam Hatchfield, Pollutants in the Museum Environment, Archetype Press, London, 2002

AMOL reCollections Glossary -http://amol.org.au/recollections/7/c/

Museum of Japanese Traditional Art Crafts at http://www.nihon-kogeikai.com/ (Jap. term)

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.

@@ Line 2: / Line 2: @@
 == Description ==
-One of two common classifications for trees, [[hardwood|hardwood]] (angiosperm) and softwood (gymnosperm). Softwoods are coniferous trees. With the exception of the larch and cypress trees, softwoods do not shed their needle-like leaves. Examples of softwood trees are: [[pine|pine]], [[fir|fir]], [[hemlock|hemlock]], [[spruce|spruce]], [[tamarack|tamarack]], [[cedarwood|Cedar]], and [[redwood|redwood]]. Softwood trees are found in temperate and mountainous regions. Most of softwoods are used for general construction, fences, and paper pulp. Softwood trees tend to have less acetic acid (1-2%) than hardwoods (3-5%) (Hatchfield 2002).
+One of two common classifications for trees, [[hardwood|hardwood]] (angiosperm) and softwood (gymnosperm). Softwoods are coniferous trees. With the exception of the larch and cypress trees, softwoods do not shed their needle-like leaves. Examples of softwood trees are: [[pine|pine]], [[fir|fir]], [[hemlock|hemlock]], [[spruce|spruce]], [[tamarack|tamarack]], [[cedar wood|Cedar]], and [[redwood|redwood]]. Softwood trees are found in temperate and mountainous regions. Most of softwoods are used for general construction, fences, and paper pulp. Softwood trees tend to have less acetic acid (1-2%) than hardwoods (3-5%) (Hatchfield 2002).
 [[File:99_Chem. softwood_conif_pol adj.jpg|thumb|Chemical softwood (coniferous)]]
@@ Line 9: / Line 9: @@
 nanboku (Jap.); bois tendre (Fr.); legno di conifera (It.); evergreen; coniferous
-== Other Properties ==
+== Physical and Chemical Properties ==
 Contain tracheids rather than pores.  May contain resin channels.
 Paper fiber type: Softwood. Using transmitted light microscopy, softwood fibers are identified by the presence of intertrachied "bordered" pits and species specific features such as ray parenchyma pits, size, width, etc. Appearance with [[Graff "C" stain]]: [[sulfite process|sulfite]]= warm pink to grey, appearance gets lighter with progressive bleaching, [[kraft process|kraft]]=grey blue to purple, appearance gets lighter with progressive bleaching. Average dimensions of fibers: species dependent (average= 3-3.6mm). Common pulping method: [[kraft process|kraft]] and [[sulfite process|sulfite]]. The long fibers of softwood pulp impart strength to paper and are often used in conjunction with [[hardwood]] and [[rag]] pulps. Softwood can be pulped [[mechanical wood pulp|mechanically]] or [[chemical wood pulp|chemically]].
-== Additional Information ==
-P.Hatchfield, ''Pollutants in the Museum Environment'', Archetype Press, London, 2002.
 == Additional Images ==