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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Duration: This supplement is effective until superseded or removed.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 |Date Approved: 03/17/2011 |

|Regional Forester | |

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|Superseded Document(s) by |2409.12_10 (Supplement 2409.12-2007-1, 08/27/2007) |8 Pages |

|Issuance Number and Effective Date | | |

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.

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 |UNIT |TREE DBH |LEN |dib SMALL |M-FAC |NOTES |

| | | |DEAD | | | |END | | |

| | | | | | | | | | |

|1 |SAWTIMBER | ALL |----------|CCF |7.0 |8.0 |5.6 |10.67x | 1, 2 |

| | | | | | | | | | |

|1 |NON-SAWTIMBER | ALL |----------|CCF |----------|--------- |------------|50.0% | 3, 4 |

| | | | | | | | | | |

|1 |CEDAR PRD. |WESTERN RED CEDAR |----------|CCF |----------|----------|------------| | 5, 6 |

| | | | | | | | | | |

12 - Exhibit 02

REGION 3 UTILIZATION SPECIFICATIONS

(Reference current R-3 Supplement to FSM 2430)

. . . . PIECE. . . .

|R |PRODUCT |SPECIES |LIVE OR |UNIT |TREE DBH |LEN |dib SMALL |M-FAC |NOTES |

| | | |DEAD | | | |END | | |

| | | | | | | | | | |

|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 |

12 - Exhibit 03

REGION 4 UTILIZATION SPECIFICATIONS

. . . . PIECE. . . .

|R |PRODUCT |SPECIES |LIVE OR |UNIT |TREE DBH |LEN |dib SMALL |M-FAC |NOTES |

| | | |DEAD | | | |END | | |

| | | | | | | | | | |

|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 |9 |

| | | | | | | | | | |

|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 & |CCF |VAR |VAR |VAR |NONE |10 |

| | | |DEAD | | | | | | |

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).

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.

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.

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

[pic]

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.

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 = 100 ft = 104.4 ft

Cos [16.70 degrees] 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.

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