The Care and Feeding
of White Woods
Tom Graber
Baillie Lumber
Smyrna, New York
Bill Smith
SUNY 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
1
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
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
2
Rotation.
3
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.
4
Rotation
Rotation
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Rotation
Rotation, not
Color Retention
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Color Retention
Color Retention
7
Color Retention
Color Retention
8
Stain
Drying environment
9
Drying environment
Drying environment
10
Drying environment
Drying environment
11
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
19
Schedule, Season, Log Age
Drying Schedules
Drying schedule for 4/4 hard maple T8-C3 (Normal color)
Step
1
2
3
4
5
6
7
Temperature in degrees F
Moisture Relative
Wet
Wet Bulb
Content Humidity Dry
(%)
(%)
Bulb
Bulb
Depression
Above 40
86
130
125
5
40 to 35
81
130
123
7
35 to 30
72
130
119
11
30 to 25
57
140
121
19
25 to 20
35
150
115
35
20 to 15
22
160
110
50
15 to
26
180
130
50
final
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Drying Schedules
Drying schedule for 4/4 hard maple T3-C5 (White color)
Step
1
2
3
4
5
6
7
Temperature in degrees F
Moisture Relative
Wet
Wet Bulb
Content Humidity Dry
(%)
(%)
Bulb
Bulb
Depression
Above 40
70
110
100
10
40 to 35
60
110
96
14
35 to 30
47
110
90
20
30 to 25
32
120
85
35
25 to 20
22
130
80
50
20 to 15
15
140
90
50
15 to
22
160
110
50
final
Spectrophotometer a*b* color values for winter harvested material
30
25
b* 20
15
10
2
4
6
T3-C5 -Fresh log
T3-C5-4wk log
T3-C5-8wk log
a*
8
10
12
T8-C3-Fresh log
T8-C3-4wk log
T8-C3-8wk log
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Spectrophotometer a*b* color values for summer harvested material
30
25
b* 20
15
10
2
4
6
a*
Summer fresh T3-C5
Summer 4wk T3-C5
Summer 8wk T3-C5
8
10
12
Summer fresh T8-C3
Summer 4wk T8-C3
Summer 8wk T8-C3
Fresh log
W
H
I 4 wk log
T
E 8wk log
Winter
Spring
Summer
N Fresh log
O
R
M 4 wk log
A
L 8wk log
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Average L* color values
90
85
80
L* 75
70
Winter Harvested
65
Summer Harvested
Spring Harvested
60
Fresh
4 wk log
8 wk log
Fresh
T3-C5
4 wk log
8 wk log
T8-C3
Air dry
Winter
Spring
Summer
Fresh
log
4 wk log
8wk log
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Average L* color values for air dried material
90
85
80
L* 75
70
Winter Harvested
Spring Harvested
65
Summer Harvested
60
Fresh
4 wk log
8 wk log
Interior Color
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@ 90F
Drying days
0.5
1
1.5
2
2.5
3
7
12
3
7
12
@ 110F
Drying days
0.5
1
1.5
2
2.5
25
@ 130F
Drying days
0.5
1
1.5
2
2.5
3
7
12
3
7
12
@ 150F
Drying days
0.5
1
1.5
2
2.5
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After 12 Days
Temperature (F)
90
110
130
150
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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