WOOD QUALITY

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WOOD QUALITY
David B. South
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WHAT IS WOOD QUALITY?
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WHAT IS WOOD QUALITY?
Wood quality is a measure of the aptness of wood
for a given use. Therefore, to some people,
straight-grained, blemish-free lumber is a sign
of high quality. To others, burls, whorls, and
curls are signs of high quality.   
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WHAT IS WOOD QUALITY?
Price/cubic foot?Wood properties?Species?Size?
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WHAT IS WOOD QUALITY?
Wood properties?
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?
Northern Hemisphere
March
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Juvenile wood or crown wood
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WOOD PROPERTIES WOOD QUALITY?
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Species and specific gravity (question why is
South Alabama lob denser?)
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Machine stress-grading leads to the
classification of timber on the basis of
structural properties, and the different groups
are directly given either F-grades or In-grade
structural properties, which are appropriate for
the whole parcel of graded timber. Machine
stress-grading is often perceived as more
objective and efficient than visual grading
methods.
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Machine stress gradingtakes the guesswork out of
grading lumber
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The assumption must be that those who can see
value only in tradition, or versions of it,deny
mans ability to adapt to changing
circumstances. Stephen Bayley
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What silvicultural practices do foresters employ
that will affect WOOD QUALITY?
Species
Genotype
Rotation length
Initial stocking
Thinning
Pruning
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OLD STATEMENTS ON WOOD QUALITY OF LOBLOLLY
PINE Loblolly or Oldfield pine This tree
cannot be given much space, as it is not only
inferior as a "thing of beauty" to many others of
its brethren, but its timber is very spongy and
not worth anything, excepting where other lumber
is hard to find. The grain is straight and
without knots, but is composed mostly of
sap-wood, and warps very badly on exposure to the
weather. (on page 105) Brisbin, J.S. 1888.
Trees and tree planting. Harper and Brothers, New
York 258 p.
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Among the pines of the southern Atlantic forests
noted for their economic importance the Loblolly
is held least in value as a timber tree. This
opinion is chiefly founded on the lesser
durability of its wood, being more speedily given
to decay under the combined influences of
dampness and air, and also on the supposition of
its being of less strength than the other pine
timbers. There is scarcely a timber tree existing
that shows wider differences in the quality and
value of the timber. This is strikingly
demonstrated when the timber of a tree of full
average growth, grown on land broken by the plow,
is compared with the timber of a tree in its
highest perfection taken from the primeval
forest. In the former case the wood is
crossgrained, sappy, and quick to decay. In the
latter it is finer grained, resinous, has less
sapwood, and approaches the timber of the
Longleaf Pine.(on page Page 117) Mohr, Charles.
1896. The Timber Pines of the Southern United
States. USDA Division of Forestry. Bulletin No.
13. 160 pages.
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Longleaf and slash pine produce better lumber
but are sawmills willing to pay the landowner
more for these species than loblolly pine?
Campbell 1964 USFS RPap SE-11
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Timber Sale Data - MississippiFrom John Guthrie
Sons, Wiggins, MS
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WHAT IS WOOD QUALITY?
Price/cubic foot?
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Relative SPECIES values over 100 years (species
the same but price per unit changes over
time) Stumpage value /MBF 1899
                                        1999
Black
Walnut     5.00           Redwood           780
CA Scribner White pine         3.66
          Black Walnut     503 MO
Elm                     3.30
         Southern Pine    356 AL Scribner
Oak (various)     3.18           Oak (various)
   354 AL Doyle Yellow poplar     2.81
         Douglas-fir        350 OR
Maple                  2.66          Yellow
poplar   185 MS Doyle Sweetgum          
1.68           Sweetgum         150 MS Doyle
Cottonwood        1.45           Maple
               141 MO
Southern Pine      1.20          Cottonwood
     125 MS Doyle Redwood           
1.00           Elm                    110 MS
Doyle Douglas-fir          0.77
         White pine         100 Conn. Maine
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WHAT IS WOOD QUALITY?
Size?
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Species and Size
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??
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Spacing and Wood Quality
juvenile
mature
old-growth
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202 323
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Juvenile wood or crown wood
Juvenile wood -10 rings Mature wood 11rings
Which spacing has a higher of the basal area in
juvenile wood?
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DBH age 10 and (30) yr
4.3 (6.6)
6.6 (12.0)
5.1 (8.1)
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basal area in juvenile woodat age 30 years
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40
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Slash pine not thinned
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Loblolly pine Piedmont SC
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Age, Spacing and Juvenile Wood
Caufield et al. 1992 table 4
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When foresters plant at low densities, concerns
over wood quality are raised.
1210 TPA
194 TPA
680 TPA
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slashage 35
In regards to paying landowners stumpage, size
is valued more than rings per inch
Pulpwood 9.6 rings/inch
Sawtimber 5.4 rings/inch
Chip-n-saw 7.8 rings/inch
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slashage 35
In regards to paying landowners stumpage, size
is valued more than rings per inch
7 per ton
46 per ton
Pulpwood 9.6 rings/inch
23 per ton
Sawtimber 5.4 rings/inch
Chip-n-saw 7.8 rings/inch
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In regards to paying sawmill owners for lumber,
size is valued more than visual grade
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Do rings per inch matter when selling pulpwood??
4 rings/inch
2 rings/inch
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WOOD PROPERTIES JUVENILE WOOD
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Do rings per inch matter when buying 2x8
lumber???
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Spacing and Specific Gravity
Clark and Saucier 1989 table 2
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Question

• For loblolly pine, what is the general
  relationship between tree stocking and average
  stand height?

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If faster grown trees are harvested at an earlier
age because they reached a certain average
diameter sooner, they will produce lower
specific gravity products. (Crown et al. 1991)
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An inherent relationship between growth rate and
specific gravity does not exist. Fast growth does
not imply lower specific gravity. Megraw 1985
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Branch size
134 330 647 1800 TPA
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Spacing and Knot Size
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Spacing and Knot Size
Figure 3. Effect of initial trees per acre on
average branch diameter of loblolly pine (Gray
bars represent data from Baldwin, Peterson,
Clark, Fergerson, Strub, and Bower 2000 black
bars are adapted from Oberg 1990).
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These loblolly pine logs were 29 years old and
had been pruned.We were amazed to be able to
saw such a high percentage of clear and premium
lumber.
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Spacing and MOR (age 40)
Slash pine
Visually graded No. 2
McAlister et al. 1997
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Spacing and MOE and MOR
Tree spacing had a minimal effect on strength
(MOR) and stiffness (MOE) of dimension lumber
sawn from unthinned 40-year-old slash pine
growing in the Georgia Coastal Plain The
unthinned 40-year-old slash pine from all
spacings sampled produced dimension lumber with
excellent mechanical properties.
McAlister et al. 1997
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Spacing and lumber value(note not stumpage
value)
Clark et al. 1992
100 ft2 basal area treatment
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Spacing and Lumber value/acreAge 38 years
Clark et al. 1992
100 ft2 basal area treatment
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Spacing, planting cost and NPV
Economic analysis using data from Clark et al.
1992
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Which is more profitable, a diamond mine or a
coal mine?
Piers Maclaren 1997
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Older trees may produce better lumber but are
sawmills willing to pay the landowner more for
older trees?
Biblis and Carino 2002 - Forest Product Journal
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Thick thin
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Thick thin
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Thick thin
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SUMMARY
For most private landowner objectives in the
South, I recommend chip-n-saw densities (300 to
450 trees per acre) for loblolly pine. These
planting rates are typical for sawtimber regimes
in New Zealand and South Africa. Pulpwood
densities of 600 to 900 trees per acre arelikely
the result of tradition and use of low quality
seedlings. They may be appropriate when pulpwood
prices are not much different than chip-n-saw
prices. High stocking targets originated in the
UK and were adopted in the 1940s and 1950s when
pulpwood production was the primary objective of
paper companies.