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P van Rijckevorsel
 
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Default ### micro-FAQ on wood # 032

I. SOME FREQUENTLY ASKED QUESTIONS ON WOOD:

Q: A Softwood is a soft wood and a Hardwood is a hard wood. Right?
A: False. A softwood is the wood of a conifer (or a Ginkgo), a hardwood is
the wood of a dicot tree. The hardest hardwood is some three times as hard
as the hardest softwood, but the hardest softwood is some four times as hard
as the softest hardwood. The softest woods in the world are hardwoods.

Q: A Conifer, that is the same thing as a Gymnosperm. Right?
A: Not quite: there are four groups of Gymnosperms, of which the Conifers
(with some six hundred species) are the biggest and most important. Ginkgo
(one species) is another such group. The remaining two groups don't yield
anything that could be regarded as timber.

Q: A wood with "cedar" in the name will surely be a softwood. Right?
A: False: "cedar" is a word that does not mean anything except a wood with a
certain type of fragrance (if that). Going only by frequency, "cedar" in the
US most often will be "Western Redcedar" (Thuja plicata), followed at some
distance by "Eastern Redcedar" (Juniperus virginiana) also marketed as
"Aromatic Cedar" [these are both softwoods]. A "cedar" from Central America
will usually be a Cedrela species; from SE Asia usually a Toona species
[these are both hardwoods]. Etc, etc[list goes on at considerable length].

Q: Slow-grown wood is harder than fast-grown wood. Right?
A: By and large, this is true. It will depend on the wood concerned. The
age-old canon is "A slow-grown softwood is harder than a fast-grown
softwood, while a fast-grown hardwood is harder than a slow-grown hardwood."
Curiously, this is also true, up to a point. It will not be true in the
tropics, but will in most of the US and Europe.
The point is that throughout most of the US and Europe the most used
hardwoods will be ring-porous (such as Ash, Elm, Hickory, Oak). A
ring-porous tree will start every year by forming a ring of very big pores
(easily visible to the naked eye) and only make mechanical tissue (for
support) later in the year. This means that in a short season the tree will
not have time to make a full growth ring, but stops after making only very
little of this mechanical tissue: slow-grown wood exists mostly of the rings
of big pores. As pores are big air-filled spaces slow-grown ring-porous
hardwood is quite soft. In a long season the tree will have the time to make
a full growth ring with a great deal of mechanical tissue. As the latter is
hard, a fast-grown ring-porous hardwood will be hard and strong.
For softwoods and diffuse-porous (non-ring-porous) hardwoods a
slow-grown wood will be harder (and more decorative) than a fast-grown wood.

Q: "Cherry" is the wood from the Cherry tree. Right?
A: Not really. The tree that cherries grow on does yield a classic wood,
called cherry, but this has always been fairly rare (these days cherry trees
are planted in a stunted form for pickability of the fruit). There is a US
timber tree ("Black Cherry", more or less closely related) that yields a
look-alike wood almost as good, and certainly a lot more available. This is
called cherry for convenience.

Q: "Brazilian Cherry "is a kind of cherry. Right?
A: False. The nearest wellknown relatives of "Brazilian Cherry" (Hymenaea),
more properly known as "Red Locust" or "Jatoba", will be Purpleheart
(Peltogyne) and Bubinga (Guibourtia). The closest relatives in the US will
be "Honey Locust" (Gleditsia) and the "Kentucky Coffetree" (Gymnocladus). A
(much) more distant relative is "Black Locust" (Robinia).

Q: What wood to use for a cutting board?
A: Maple, or something similar (any lightcolored hardwood, with a high
density and a fine structure, e.g. beech, birch, etc). Not to be recommended
are exotic hardwoods: their high degree of durability is because they
contain significant concentrations of exotic substances lethal to lots of
organisms. These substances are best avoided in food. The issue is
especially relevant when cooking for guests or children.

Q: A Live Oak is an oak that has not been cut down yet. Right?
A: False. A Live Oak is another name for an evergreen oak (OK, sometimes a
"subevergreen" oak). Evergreen oaks occur where the temperature allows, in a
belt all round the world. Going by the wood, there are three categories of
genuine Oak (Quercus), found all over the Northern Hemisphe White Oaks,
Red Oaks and Live Oaks. The woods of these three are not closely comparable
in any respect. Characters that are shared by all three woods are prominent
rays and a dendritic arrangement of pores. All in all there are some 400
species of genuine Oak. In addition there are any number of woods called
Oak, for whatever reason strikes the fancy of a wood trader.

Q: "Phillipine Mahogany" is mahogany from the Philippines. Right?
A: False. It may or may not be from the Philippines (probably not), but it
won't be Mahogany, ever.

Q: "Honduras Mahogany" is mahogany from Honduras. Right?
A: Depends. It could be, but usually is not (from Honduras, that is).

Q: "African Mahogany" is mahogany from Africa. Right?
A: Just about. The wood of Khaya is from tropical Africa and is usually
assumed to be a Mahogany.

Q: "Rhodesian Teak" is teak from Rhodesia. Right?
A: False. Baikiaea plurijuga is not teak, but a member of the Pea family. It
grows in several countries, one of which used to be called Rhodesia.

Q: "Nigerian Teak" is teak from Nigeria. Right?
A: Right. Plantation grown. Not that anybody would want to use it.

Q: "Java Teak" is teak from Java. Right?
A: Right. Plantation-grown, from the days the Dutch were there. High
quality.

Q: Teak is a really hard wood. Right?
A: Depends. Teak (Tectona grandis, family Labiatae) varies from soft as
butter and pale yellow to fairly hard and dark brown. Depends on provenance.

Q: Steel is stronger than wood. Right?
A: Depends. A piece of steel of a certain size will almost always be
stronger as a piece of wood the same size. A steel rod of a particular
length and mass as compared to a similarly sized rod of wood ...

* * *

II. SOME USEFUL SITES:

FPL:
- intro-page of the Forest Products Laboratory:
http://www2.fpl.fs.fed.us/

- technical properties of wood
http://www2.fpl.fs.fed.us/TechSheets/techmenu.html
including two downloadable books on US-Woods

- the FPL "Wood Handbook. Wood as an engineering material"
(downloadable):
http://www.fpl.fs.fed.us/documnts/fp.../fplgtr113.htm
(Hardcopy at Lee Valley)

- common and scientific names of wood
(best database around, with a fairly low level of error):
http://www2.fpl.fs.fed.us/CommNames2000.html

- silvics of US trees
http://www.na.fs.fed.us/spfo/pubs/si...f_contents.htm

or
http://www.fpl.fs.fed.us/tmu/publications.htm

OTHER SOURCES:
- "The American Woods":
(http://www.lib.ncsu.edu/archives/forestry/hough/
(pictures only; a similar set is now in print as "the Woodbook")

- lots of pictures (fun), but short on accuracy and real information
full version (slow):
http://www.hobbithouseinc.com/person...indextotal.htm
small version (faster):
http://www.hobbithouseinc.com/person...pics/index.htm

Some more pictures (very little information; not free of typo's)
http://www.woodworking.org/WC/woodsampler.html

a preliminary page on purpleheart
(the wood of the genus Peltogyne, family Leguminosae):
http://www.organicsculpture.com/Purpleheart.html

a bird-eye's view of dangers:
http://www.city-net.com/albertfp/toxic.htm
http://www.ubeaut.com.au/badwood.htm

for a more extensive link-page see:
http://www.nehosoc.nl/paginalinks.htm

under reconstruction:
http://www.woodcollectors.org/

availability of wood (US)
http://www.woodfinder.com/

* * *

III. BOOKS:
Good entry-level books on wood are
"Good Wood Handbook" by Albert Jackson & David Day
(cheapest and best, just dropped out of print?)
"Woodworker's Guide to Wood" by Rick Peters ('passing grades')

An interesting book on a different way to obtain wood:
"Harvesting Urban Timber" by Sam Sherrill

Adult books on wood are
"Understanding Wood" by R. Bruce Hoadley
"Identifying Wood" by R. Bruce Hoadley

For those not shying away from a thick book:
"Holzatlas" by Rudi Wagenfuhr





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