Is there a better measure for
roundwood than the
Board Foot ?
Neal Hart, Jendro & Hart, LLC
Timber Measurement Society, Central Meeting - Portland, Oregon
April 8, 2010
Three common, but false, presumptions
about Board Foot measurements:
1. A "board foot" is the
same in log and
lumber measurement
2. Board foot log scales
accurately predict
lumber volume
Like:
Feet x 0.3048
= Meters
3. The ratio of board feet
to other scales is a
single precise factor
What’s One Board Foot ?
It depends on what’s being measured!
Logs
Dimension Lumber
144 in.3
81 in.3 95 in.3 110 in.3
1” X 4” +
Scribner
2” X 2”
2” X 4”
4” X 4”
Lumber Tally
Scribner &
st
21
th
19
Century
Technolog
y
Large End of Log
Lumber Tally
Small End of Log
Century
Technology
Large End of Log
Small End of Log
Tradition!
Why stick with Scribner?
Board Foot Measurement and
Sawmill Margin Analysis
BF
Log
BF
?
Lumber
Sawmill Margin “Per MBF”
Lumber
Sawdust &
Shavings
Chips
Period
Period
1
2
Change
Lumber
Tally $100
$600 $700
less
$300
$500 $200
Scribner
Logs
equals
$300 $200 ($100)
Nonsense!
Margin
Sawmill Lumber Recovery
BF Lbr Per:
Period
Period
1
2
Change
BF Scribner 1.00 1.43 +43%
Cubic Foot 3.83 5.29 +38%
Sawmill Margin Per MBF LT
Lumber
Sawdust &
Shavings
Chips
less
Logs
Period
Period
1
2
Change
$600 $700 $100
$300 $350 $50
equals
Margin
$300 $350 $50
It’s easier to believe
false presumptions
than to believe the truth
about board foot
measurement!
Sawmill Revenue Per MBF LT
Lumber
Sawdust &
Shavings
Chips
Period
Period
1
2
Change
$600 $700 $100
The Change in Per-Unit Revenues
Expressed in Lumber Tally Does Not
Show the Change in Lumber Recovery
Between Periods
Sawmill Revenue Per CCF
Lumber
Sawdust &
Shavings
Period
Period
1
2
Change
$230 $370 $140
Chips
Price Change:
TheMBF
Change
Per-Unit
$100/
LT xin0.529
MBFRevenues
LT per CCF = $53
Expressed
in Cubic Scale Does Show the
Recovery
Change:
Change in Lumber Recovery Between
Per. 1 Rev. $230/CCF x 38% increase = $87
Periods
Total Change: $140
Sawmill Margin Per CCF
Lumber
Sawdust &
Shavings
Period
Period
1
2
Change
$230 $370 $140
Chips
less
Logs
$115 $185 $70
equals
Margin
$115 $185 $70
What’s the Cost of Scribner?
Confusion about “board foot”
scaling has led to costly errors
and litigation involving
hundreds of $ Millions
Converting Between Cubic
& Board Foot Log Scales
CF
?
BF
Common, but false, presumptions about
Board Foot measurements…
Like:
3. The ratio of Board Feet
MBF x 4.53 =
to other log scales is
a single precise factor
Cubic Meters
Cubic
Scribner
Single Precise Conversion Factor is
Promoted by Industry Literature
Assumes a
BF = 144 in.3
“Production, Prices, Employment, and Trade in
Northwest Forest Industries, All Quarters” July 2009
Single Precise Conversion Factor is
Promoted by Industry Literature
Assumes a
BF = 144 in.3
Assumes a
BF = 104 in.3
“U.S. Timber Production, Trade, Consumption, and
Price Statistics 1965 to 2005” Sept 2007
Single Precise Conversion Factor is
Promoted by Industry Reports
March 27, 2009
Implies 19”- 20” ave. SED!
Cubic Meters per MBF Scribner LLS
13
12
Dual-Scale for Half Million Logs
11
10
RC & AYC
9
8
DF & WW
Average & 90% data range
7
6
5
5.13
4.53
4
3
6
8
10
12
14
16
18
20
Diameter Small End (in.)
22
24
26+
Cubic Meters per MBF Scribner LLS
830 Hemlock Logs
8”-11” dib
13.5
12.0
10.5
9.0
7.5
6.0
Mean +/- 1 Std dev
4.5
7
8
9
10
Diameter Small End (in.)
11
12
Cubic Meters per MBF Scribner LLS
13.5
830 Hemlock Logs
8”-11” dib
12.0
10.5
8"
9.0
9"
Confidence interval at 1 Std error is:
6.1 – 8.6 m3/MBF
7.5
6.0
10"
11"
4.5
0.0
0.5
1.0
1.5
2.0
Inches of Taper per Ten Feet of log Length
2.5
$/MBF Scribner Equal to $65/m3
$900
830 Hemlock Logs
8”-11” dib
$800
$700
8"
$600
9"
Confidence interval at 1 Std error is:
$387 - $551 per MBF
$500
$400
10"
11"
$300
0.0
0.5
1.0
1.5
2.0
Inches of Taper per Ten Feet of log Length
2.5
So, despite what some
industry literature suggests…
There is No Single Factor
to convert Board Feet to Cubic!
CF
?
BF
Converting Among Log Scales in
US-Canada Price Comparisons
m3/MBF Short Log Scribner
BC
Interior
$/m3
BC Metric
US
Inland PNW
$/MBF
Short Log Scribner
(Cahill 1984)
8
7
6
5
4
6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Log Diameter Small End (in.)
Converting Among Log Scales in
US-Canada Price Comparisons
m3/MBF Short Log Scribner
(Cahill 1984)
US $25.15/m3 x 6.77 = $170/MBF
Dual-Scale conversion
BC
Interior
8
7
Yr Ending
3/31/01
factor is 6.77 m3/MBF
for BC Interior
Lodgepole & Spruce
sawlog harvest
6
US $179/MBF - $170/MBF = $9/MBF
5
US Inland PNW
4
6 7 of
8 9Timber
10 11 12 13 Costs
14 15 16 17 18 19 20
Indicates Approx. Parity
Log Diameter Small End (in.)
Converting Among Log Scales in
US-Canada Price Comparisons
Short Log Scribner
“The most appropriate approachm3/MBF
to m3/MBF
(Cahill 1984)
US$25.15/m3
x
4.81
=
$121/MBF
conversions would be for Commerce to use a standard,
US Dept. of Commerce
BC
8
published,Interior
average factor…
uses a conversion factor
of 4.81 m3/MBF for BC
Yr Ending
The
most widely accepted7 such factor
is 4.53
m3/MBF.
”
Interior
Lodgepole
&
Spruce sawlog harvest
3/31/01
6
“In fact, alone, its very longevity and stability suggest
-5$121/MBF
$58/MBF
that, as aUS$179
general/MBF
approximation,
it is =reasonably
accurate.”US Inland PNW
4
6 7Diff.
8 9 10
11 12
15 16 17 18 19 20
US DOC
$58
as
a 13Subsidy
ExpertDeclares
for “Coalition for
Fair Lumber
Imports
”14
January
2002
Log Diameter Small End (in.)
Converting Among Log Scales in
US-Canada Price Comparisons
BC
Interior
During 2002 - 2006 the US
Government charged approx.
$1.5 Billion in tariffs on
BC Interior manufacturers of
Lodgepole & Spruce lumber
US
Inland
PNW
Virtually all those tariffs
resulted from incorrect
conversion between US
Scribner & BC Metric scale
What’s the Cost of Scribner?
In the case of Canada – US
lumber trade, use of Scribner
instead of Cubic in the U.S.
has led to $ Billions in tariffs
and litigation costs
Is there a better measure for
roundwood than the
Board Foot ?
I Say it’s Cubic!