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1
The Care and Feeding of White Woods
Tom GraberBaillie Lumber
Smyrna, New York
Bill SmithSUNY ESF
Syracuse, New York
The Care and Feeding of White Woods
Kinds of:• Challenges:
1) Rotation. 2) Color Retention (interior and
exterior)3) Stain (fungal, chemical,
and…) 4) Drying environment (Air
Drying and kilns) 5) Dimensional stability 6) Kiln / boiler limitations 7) Bruising 8) Stick Shadow 9) Mixed loading / MC variation
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The Care and Feeding of White Woods
Kinds of:• Solutions:
1) Fast from tree to thee as fast as possible.
2) Scheduling, winter cut, fast rotation
3) storage, scheduling…4) high airflow, low temp / RH
schedule 5) Cutting, sticking, stacking,
rotation 6) Airflow, heating / venting
capacity 7) Eliminate sawmilling process 8) Breeze dry sticks / dry sticks 9) LCD scheduling
The Care and Feeding of White Woods
Kinds of:• Challenges:
1) Rotation. 2) Color Retention (interior and
exterior)3) Stain (fungal, chemical,
and…) 4) Drying environment (Air
Drying and kilns) 5) Dimensional stability 6) Kiln / boiler limitations 7) Bruising 8) Stick Shadow 9) Mixed loading / MC variation
• Solutions:1) Fast from tree to thee as fast as
possible.2) Scheduling, winter cut, fast
rotation3) storage, scheduling…4) high airflow, low temp / RH
schedule 5) Cutting, sticking, stacking,
rotation 6) Airflow, heating / venting
capacity 7) Eliminate sawmilling process 8) Breeze dry sticks / dry sticks 9) LCD scheduling
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Rotation.
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The Care and Feeding of White Woods
• Rotation – basic steps:1) Winter – Have lumber in the kiln before tree knows it is dead. 2) Spring, Summer, Fall – Have lumber in the kiln before the tree hits
the ground.
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Rotation
Rotation
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Rotation
Rotation, not
Color Retention
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Color Retention
Color Retention
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Color Retention
Color Retention
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Stain
Drying environment
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Drying environment
Drying environment
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Drying environment
Drying environment
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Dimensional stability - stacking
Dimensional stability - stacking
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Dimensional stability - sticking
Dimensional stability - stacking
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Dimensional stability - full courses
Kiln / boiler limitations
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Kiln / boiler limitations
Bruising
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Stick Shadow
Mixed loading / MC variation
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Mixed loading / MC variation
Mixed loading / MC variation
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Some SUNY ESF Laboratory Research
Spectrophotometer Color Analysis
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What is color?
Lab color space
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Schedule, Season, Log Age
Drying SchedulesDrying schedule for 4/4 hard maple T8-C3 (Normal color)
Temperature in degrees F
501301802615 to final
7
501101602220 to 156
351151503525 to 205
191211405730 to 254
111191307235 to 303
71231308140 to 352
512513086Above 401
Wet Bulb
Depression
Wet
Bulb
Dry
Bulb
Relative
Humidity (%)
Moisture Content
(%)Step
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Temperature in degrees F
501101602215 to final
7
50901401520 to 156
50801302225 to 205
35851203230 to 254
20901104735 to 303
14961106040 to 352
1010011070Above 401
Wet Bulb
Depression
Wet
Bulb
Dry
Bulb
Relative
Humidity (%)
Moisture Content
(%)Step
Drying SchedulesDrying schedule for 4/4 hard maple T3-C5 (White color)
Spectrophotometer a*b* color values for winter harvested material
10
15
20
25
30
2 4 6 8 10 12a*
b*
T3-C5 -Fresh log T8-C3-Fresh logT3-C5-4wk log T8-C3-4wk logT3-C5-8wk log T8-C3-8wk log
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10
15
20
25
30
2 4 6 8 10 12a*
b*
Summer fresh T3-C5 Summer fresh T8-C3 Summer 4wk T3-C5 Summer 4wk T8-C3 Summer 8wk T3-C5 Summer 8wk T8-C3
Spectrophotometer a*b* color values for summer harvested material
Fresh log
4 wk log
8wk log
Winter Spring Summer
Fresh log
4 wk log
8wk log
WHITE
NORMAL
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Average L* color values
60
65
70
75
80
85
90
L*
Winter Harvested
Summer Harvested
Spring Harvested
Fresh 8 wk log4 wk logFresh 8 wk log4 wk log
T8-C3T3-C5
Fresh log
4 wk log
8wk log
Winter Spring Summer
Air dry
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60
65
70
75
80
85
90
L*
Winter Harvested
Summer Harvested
Spring Harvested
Fresh 8 wk log4 wk log
Average L* color values for air dried material
Interior Color
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Drying days
0.5 1 1.5 2 2.5 3 7 12
@ 90F
Drying days
0.5 1 1.5 2 2.5 3 7 12
@ 110F
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Drying days
0.5 1 1.5 2 2.5 3 7 12
@ 130F
Drying days
0.5 1 1.5 2 2.5 3 7 12
@ 150F
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Temperature (F)
90 110 130 150
After 12 Days
CONCLUSIONS
•Critical temperature to cause interior darkening seems to be around 110 F
•The proof:
1. Interior darkening started immediately with above 130F drying
2. 90F drying did not result with interior darkening.
3. During 110F drying, interior darkening started when core temperature plateaus.
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Past experience ….
Interior darkening developed above FSP.
Not much color change developed below FSP
In this study:
2 days at Core temp. 110 F, AMC 30, Core MC higher than FSP, Darkening has started.
3 days at Core temp. 110F, AMC 20, Core MC is around FSP, Darkening progresses.
5 days at Core temp. 110F, AMC 15, Core MC below FSP,
Darkening ended.
Recommendation
•Keep core temp below 110 F until Core MC is
•below FSP (average MC below 20%)
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Some of our competition...In China
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Thank you!any Question, Comments?
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