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WETTABILITY OF SOUTHERN PINE
SUBJECTED TO BARK BEETLE
FUNGAL ASSOCIATES
By
Eric McConnell, Nathan Little, Nate Irby,
John Riggins, and Sheldon Shi
Forest Products Society, Portland OR
Primary Species of the Southern Pine Bark Beetle Guild
3 species of Ips
Black Turpentine Beetle (D. terebrans)
Southern Pine Beetle (D. frontalis)
Southern Pine Beetle
(D. frontalis)
• Last Major Outbreak in
South ~10 years ago
• $1 billion in damages
• Environmental and social
impacts as well
• Initially overcomes
oloeresin
• Inoculating a variety of
fungi
• O. minus most prolific
early
• Death occurs through
many factors
– Gallery and fungal
proliferation
• Timely salvaging can
produce lumber
– LRF
– Grade
• Decay fungi and
termites soon after
What About Composites?
• Kelly et al (1982)
utilized SPB-killed trees
in mixture with healthy
• MOR, IB, & SW
• 2 & 24 hour
TS & WA
• No proposed
explanation
What About Composites?
• Adhesive must
adequately penetrate for
effective bonding
• Wicking occurs via
capillary forces
• Provides intimate
contact
• Better understanding
resin-wood interface
may provide economic
uses for biologically
attacked timber
• MS overdue for an
outbreak
Goals
• Determine DCA of
– Green and Kiln-dried SYP
– With and without blue
stain present
– Wilhelmy Plate
• Calculate surface energy
– Geometric mean
Avg. Dynamic Contact Angles
Probe Liquid [Surface tension]
Water
[72.8 mJ/M2]
α-
Bromonapthalene
[44.4 mJ/M2]
Formamide
[58.0 mJ/M2]
Ethylene Glycol
[48.0 mJ/M2]
Wood Type Average contact angle (standard deviation)
Green SPB
blue-stain51.1 (2.6) 29.4 (3.5) 52.7 (1.5) 41.4 (1.6)
Kiln-dried
control45.4 (4.1) 9.4 (9.1) 45.1 (2.6) 42.0 (1.7)
Green
control47.0 (8.3) 16.1 (11.5) 42.8 (10.5) 39.3 (3.0)
Kiln-dried
blue-stain0.0 (0.0) 0.0 (0.0) 52.8 (0.3) 34.4 (4.6)
Geometric Mean
d
L
p
Lp
S
d
Sd
L
L
5.0
*
*2
*)cos1( 5.05.0
5.0 )()(
xY 1
Surface Energies
TreatmentDispersive
forces
Polar
forces
Total surface
energy
Green
SPB blue-stain28.42 17.92 46.34
Kiln-dried control 31.37 18.84 50.21
Green control 31.86 18.40 50.26
Kiln-dried blue-stain 25.03 34.46 59.49
• Once beetle attack
occurs, various changes
take place
– Anatomical
– Morphological
– Chemical
– Physical
• All affect surface
energy
• O. minus initially
confined to ray
parenchyma in sapwood
• Cause water-conducting
blockages through
internal wounding
• Resin formation results
to slow fungal spread
• Subsequent penetration
of tracheids results in
movement across cells
via pit pairs
• Permeability
• “Stained” areas suffer
moisture loss
• Increased permeability would allow for
increase liquid transport across the grain
• KD/BS wood would have had a greater degree
of fluid flow in 3 directions
• Chemicals from tree’s wound response may
have disrupted liquid movement in Gr/BS
wood
• One possible mechanism
described for improving
board properties
• Future studies
– Other processes
– Various sized wood
elements
Conclusions
• Little change in non-
stained wood following
drying
• KD/BS wood surface
energy higher than
others
– >15% over each wood
type
Conclusions
• Wound response
possibly contributed to
lower surface energy in
Gr/BS wood
• BS wood from beetle-
killed trees may yield
properties for wood
composites
• Timely utilization is key
Thank You
For More Information
