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FOREST SERVICE HANDBOOK
INTERMOUNTAIN REGION (REGION 4)
OGDEN, UT
FSH 2409.12 – TIMBER CRUISING HANDBOOK
CHAPTER 10 – PRINCIPLES OF MEASURING TREES
Supplement No.: 2409.12-2011-1
Effective Date: April 4, 2011
Duration: This supplement is effective until superseded or removed.
Approved: HARV FORSGREN
Regional Forester
Date Approved: 03/17/2011
Posting Instructions: Supplements are numbered consecutively by Handbook number and
calendar year. Post by document; remove entire document and replace it with this supplement.
Retain this transmittal as the first page(s) of this document. The last supplement to this
Handbook was 2409.12-2007-1 to Chapter 10.
New Document(s):
2409.12_10
7 Pages
Superseded Document(s) by
Issuance Number and
Effective Date
2409.12_10 (Supplement 2409.12-2007-1,
08/27/2007)
8 Pages
Digest:
12 – Exhibit 03 – Removes Dry Logs from the Region 4 utilization specifications. Footnote 9
updated to include percent defect in the cruise will be made for prominent cracks greater than or
equal to one inch wide.
R4 SUPPLEMENT 2409.12-2011-1
EFFECTIVE DATE: 04/11/2011
DURATION: This supplement is effective until superseded or removed.
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FSH 2409.12 – TIMBER CRUISING HANDBOOK
CHAPTER 10 – PRINCIPLES OF MEASURING TREES
12 - TREES MERCHANTABILITY SPECIFICATIONS
Exhibits 01-03, shown below, provide utilization standards. The standards are Region-specific
and closely tied to Regional appraisal, pricing, and contract practices. Use the standards as
shown, and except as noted, obtain Regional Forester approval when different standards are
needed.
12 - Exhibit 01
REGION 1 UTILIZATION SPECIFICATIONS
. . . . PIECE. . . .
R PRODUCT
SPECIES
LIVE
OR
DEAD UNIT
1
SAWTIMBER
ALL
----------
CCF
1
NON-SAWTIMBER
ALL
----------
CCF
1
CEDAR PRD.
WESTERN RED ---------CEDAR
TREE
DBH
7.0
LEN
dib
SMALL
END
M-FAC
8.0
5.6
10.67x
1, 2
50.0%
3, 4
---------- --------- ------------
CCF ---------- ---------- ------------
NOTES
5, 6
12 - Exhibit 02
REGION 3 UTILIZATION SPECIFICATIONS
(Reference current R-3 Supplement to FSM 2430)
. . . . PIECE. . . .
LIVE
OR
DEAD UNIT
TREE
DBH
LEN
dib
SMALL
END
M-FAC
R PRODUCT
SPECIES
NOTES
3 SAWTIMBER
ALL CONIFER
LIVE
CCF
9.0
8.0
6.0
10.67x
7
3 SAWTIMBER
ALL CONIFER
DEAD
CCF
9.0
8.0
6.0
10.67x
7
3 SAWTIMBER
ASPEN & O.
HDWDS
LIVE
CCF
9.0
8.0
6.0
8.00x
7
3 SAWTIMBER
ASPEN & O.
HDWDS
DEAD
CCF
9.0
8.0
6.0
8.00x
7
3 NON-SAW
ALL SPECIES
LIVE
CCF
5.0
10.0
4.0
N/A
7, 8
3 NON-SAW
ALL SPECIES
DEAD
CCF
5.0
10.0
4.0
N/A
7, 8
R4 SUPPLEMENT 2409.12-2011-1
EFFECTIVE DATE: 04/11/2011
DURATION: This supplement is effective until superseded or removed.
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FSH 2409.12 – TIMBER CRUISING HANDBOOK
CHAPTER 10 – PRINCIPLES OF MEASURING TREES
12 - Exhibit 03
REGION 4 UTILIZATION SPECIFICATIONS
. . . . PIECE. . . .
LIVE
OR
DEAD UNIT
TREE
DBH
LEN
dib
SMALL
END
M-FAC
R PRODUCT
SPECIES
NOTES
4 SAWTIMBER
ALL EXCEPT
LPP
LIVE
CCF
8.0
8.0
6.0
10.67x
4 SAWTIMBER
ALL EXCEPT
LPP
DEAD
CCF
8.0
16.0
6.0
10.67x
4 SAWTIMBER
LODGEPOLE
PINE
LIVE
CCF
7.0
8.0
6.0
10.67x
4 SAWTIMBER
LODGEPOLE
PINE
DEAD
CCF
8.0
16.0
7.0
10.67x
9
4 NON-SAW
ALL SPECIES
LIVE &
DEAD
CCF
VAR
VAR
VAR
NONE
10
9
UTILIZATION TABLE NOTES
1. A 6.0” dbh can be used without Regional Office approval (Region 1).
2. A 4.6” dib can be used without Regional Office approval (Region 1).
3. To be used for all non-saw products except Cedar Products in Region 1 Sawlog
contracts.
4. Specifications determined on site specific basis (Region 1).
5. Do not include cedar products as a pulpwood tree (Region 1).
6. Reference is made to C6.804 – SCALING CEDAR PRODUCTS and CT6.804 –
MEASURING CEDAR PRODUCTS (Region 1).
7. Exhibit 02 shows typical product specifications, but these may vary for some projects.
Check appraisal and contract plans, as well as the current R-3 supplement to FSM 2430.
8. Include only material that is reasonably straight and sound (Region 3).
R4 SUPPLEMENT 2409.12-2011-1
EFFECTIVE DATE: 04/11/2011
DURATION: This supplement is effective until superseded or removed.
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CHAPTER 10 – PRINCIPLES OF MEASURING TREES
9. No deductions will be made for weather checks. Percent defect in the cruise will be
made for prominent cracks greater than or equal to one inch wide (Region 4).
10. Non-saw is material other than sawtimber that is sold by the piece, as cull material or
biomass. Variable, to be set by the Forest Supervisor, not to exceed the minimum sawtimber
specifications for that species (Region 4).
13 - TREE MEASURING INSTRUMENTS
13.13 – Dendrometers
The CRITERION - Laser functions as a fixed, optical fork dendrometer when used for
measuring stem diameters. It has a 2.5 power scope with a cross hair reticle for aiming, and a
pattern of graduated tick marks on the horizontal reticle. A laser range finder measures baseline
distance, a fluid tilt sensor measures vertical angles, and an electronic fluxgate compass
measures horizontal angles. The instrument has options for taking a number of cruising and
surveying measurements.
In use, the Criterion’s standard diameter function provides a diameter at any point on a tree.
Built-in software calculates the diameter using baseline distance, vertical angle, and the number
of reticle graduations subtended by the tree stem when viewed through the scope. The conical
projection function identifies the point (height above ground) on the stem where a particular
diameter occurs (such as a 4-inch merchantable top). This option requires a diameter reading at
a point where the stem diameter is less than the targeted diameter, and one at a point where the
stem diameter is larger than the targeted diameter. The Criterion’s software mathematically
projects taper between the two diameter readings to identify the point of the specified diameter.
As with other optical forks, move the instrument with any sway of the tree to keep the fork angle
in alignment with the bole, make all sightings at right angles to the lean, and periodically check
the instrument calibration to prevent bias. Mounting the laser on a tripod provides the best
precision.
13.28 - Laser Measuring Devices
The CRITERION Laser described in section 13.13a, of the parent text, also provides options for
taking height measurements.
14 - MEASURING THE TREE
In addition to the items described in the parent text, the following items may need to be
measured since they are required parameters in one or more volume and product estimators, or
for value analysis.
1. Upper stem diameter at a prescribed height.
R4 SUPPLEMENT 2409.12-2011-1
EFFECTIVE DATE: 04/11/2011
DURATION: This supplement is effective until superseded or removed.
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CHAPTER 10 – PRINCIPLES OF MEASURING TREES
2. Height to a prescribed stem diameter.
3. Height to the first live limb (HFLL).
4. Tree grade.
Procedures for measuring these tree variables are described in subsequent paragraphs, along with
additional notes and specific direction on items listed in the parent text. Specific instructions for
measurement instruments are found in the appropriate owners manual.
14.1 - Measuring Tree Diameter
Upper-stem diameters are used for a number of applications, including: (1) to determine a tree's
form class, (2) as a second stem diameter measurement for use in certain volume or product
estimators, (3) to calculate face width in some tree-grade procedures, or (4) to identify the point
where the minimum merchantable top diameter is located.
Choose the instrument and procedure best suited for the desired level of precision and
accessibility to the point being measured. Greatest precision is attained using a diameter tape or
caliper, and climbing the tree or cutting it down. A dendrometer is often more practical, and
provides acceptable results for most cruising situations. If needed to achieve a desired precision,
mount the dendrometer on a tripod.
First identify the target point on the stem where the diameter is to be taken. This is usually
specified as a height above a 1-foot stump, or as a height from the high ground side of the tree
base (as for d.b.h. at 4.5 feet). The target point may be at a fixed height, or specified at any point
within a prescribed range. Adjust the instrument position as needed to obtain a clear view of
both the instrument's scale and the appropriate part of the tree stem. When the measurement can
be taken to a point within a range, such as 25-35 percent of total height, choose a point that
provides a clear view.
14.12 - Measuring Tree Diameter at Breast Height (d.b.h.)
Diameter at breast height is measured from the surface of the forest floor. Use the following
guidelines to find the point.
1. The forest floor is the surface of the needle or leaf layer when litter is present or the
surface of mineral soil when litter is absent. Measure from existing needle or leaf layers, even if
other sides of the tree meet bare ground. Measure from the existing soil surface even if it
appears part of the original soil has been washed away.
2. Unless the tree is clearly growing on an object as described in section 14.12e of the
parent text, ignore common root protrusions that are often slightly above ground.
R4 SUPPLEMENT 2409.12-2011-1
EFFECTIVE DATE: 04/11/2011
DURATION: This supplement is effective until superseded or removed.
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3. Move or work between slash and similar objects that prevent measuring from the
forest floor. When immovable objects, such as logs or boulders block access to the forest floor,
offset the height measurement slightly to the side, back away from the tree base, or otherwise
compensate for the height of the object. Exhibit 01 illustrates a procedure to use when an
immovable object blocks access to the forest floor.
14.12 - Exhibit 01
Measuring DBH - Normal Case
14.2 - Measuring Tree Heights
The Region 3 volume estimator for Ponderosa pine (over 17.0 inches d.b.h.) requires a height
measurement to the first live limb (HFLL). In this context, HFLL is the point where the bottom
of the lowest live limb is connected to the tree bole. A live limb has at least one green needle.
Severely burned trees, or trees felled and limbed, may lack evidence for the HFLL measurement.
In this situation, develop a value based on comparison of trees in the general area.
R4 SUPPLEMENT 2409.12-2011-1
EFFECTIVE DATE: 04/11/2011
DURATION: This supplement is effective until superseded or removed.
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CHAPTER 10 – PRINCIPLES OF MEASURING TREES
14.21 - Baseline Distance
For convenience, an expanded table of slope correction factors is provided in regional
supplement, section 91, exhibit 02. It shows correction factors for 1 percent increments of slope
ranging from 1 to 150 percent. The formula for calculating the slope correction is shown below:
Slope distance = desired baseline distance
cos [arctan(slope%)]
Example: Slope distance:
=
100 ft
=
100 ft
Cos [arctan (30% slope)]
Cos [arctan(0.30)]
100 ft
=
Cos [16.70 degrees]
100 ft = 104.4 ft
0.9578
14.23 - Leaning Trees
Correct height measurements when lean exceeds 25 percent slope (14 degrees). The parent text
provides a Table of corrected heights based on the measured vertical height and horizontal
displacement of the top of the tree from the base. Regional supplement, section 91 provides an
expanded table showing corrections for vertical heights ranging from 30 to 210 feet.