Attachment 12 - Basic Cruising Guide.pdf

Basic Cruising Guide

Types of Cruising

There are many ways to cruise a sale. Depending on the type of cruise used, it can be done during the marking process or after. These are the cruise types that we are most likely to use.

Sample Tree Usually used in small sales. Can be done while marking. Each cut tree is counted, and some sample cut trees are measured. For every species present, 1 tree in every so many trees are a sample tree.

Sample Ratio Example: 1 in every 10 ponderosa pine trees is measured 1 in every 15 douglas fir trees is measured 1 in every 30 grand fir trees is measured

The sample tree is picked at random via a random number chart or a Portable Data Recorder (PDR).

Sample trees are marked differently than the others and their location is recorded with a GPS unit so that they can easily be check cruised.

3P Cruising Probability Proportional to Prediction

3P cruising is like sample tree cruising because the cruise can be done while or after marking and each cut tree is counted. It is different from sample tree cruising because there is no sample ratio. A tree will be selected as a sample tree depending on its Keep performance indicators (KPI).

KPI is an estimated volume that is based off an estimated diameter. When each tree is counted, it’s diameter will be estimated and the correlating KPI number will be recorded. Each crew member will have a KPI card:

The KPI value is then compared to a number selected by the PDR. If the KPI is larger than that number, the tree is a sample tree.

The sample trees are marked differently than the other trees and marked with a GPS unit so that they can easily be check cruised.

It is a good idea to get a feel for visually estimating DBH before you do a 3P cruise. It is more important for your estimates to be consistent than accurate. You don’t want to start second guessing yourself in the middle of a 3P cruise and break consistency.

Plot Cruising Good for larger sales. Usually it is done after the marking is completed. When plot cruising, you measure every merchantable tree that falls within the plot. Plot locations are usually found by using GPS units or Avanza. There are two types of plots. Fixed plots and variable plots.

DBH Kpi DBH Kpi 8 6 45 517 9 8 46 537 10 8 47 558 11 12 48 578 12 17 49 599 13 22 50 619 14 26 51 640 15 31 52 661 16 36 53 681 17 40 54 702

Gross CF Volume Estimators

Fixed Plot Plot cruising is area based. We measure the trees on multiple plots and then run the statistics to predict the volume of the entire unit. To be on the plot, a tree must be within the plot’s radius. Plot sizes are a fraction of an acre.

Example: 1/20-acre plot…. circular plot with a 26.33 ft. radius 1/50-acre plot…. circular plot with a 16.65 ft. radius 1/3-acre plot…. circular plot with a 67.98 ft. radius

Variable Plot Variable plot cruising is based on basal area. Basal area is the cross-sectional area of a tree. We use a specific basal area factor (BAF) to estimate how many square feet of tree stems will cover an acre of the unit. Determining which trees to measure depends upon each tree’s size and distance from the plot center.

Determining in/out trees on Fixed Plots

Determining which trees are in the plot is relatively easy for fixed plots. To be a measure tree, the distance between the tree’s center and the plot center must be equal to or less than the plot radius. The plot radius depends on what plot size is being used (1/20-acre, 1/30-acre, etc.).

Typically, cruisers will measure the distance from plot center to the face of the tree with a laser or to the middle of the tree with a logger’s tape. When using a tape, keep in mind that you need to measure the horizontal distance, not the slope distance. When using a laser, remember that trees are only “in” if the tree’s center is within the plot radius, not the tree’s face. If the tree’s center is clearly within the plot radius, count and measure the tree. If the measured distance is uncomfortably close to the plot radius you will have to use the limiting distance formula.

Limiting Distance Formula for Fixed Plots:

Limiting Distance = (Plot Radius – (DBH/24)) (Slope Correction Factor)

Plot Size Plot Radius 1/20-acre plot 26.33 feet 1/10-acre plot 37.24 feet

Etc.… Act…

Steps to take:

1. Get DBH. Record.

2. Take a slope measurement from the face of the tree at DBH to the top of the plot stake.

Record.

3. Insert nail on tape into the face of the tree facing plot center. Push it in hard, you don’t want it to pop out unexpectedly.

4. Pull tape to plot center. Make sure it is straight, despite what obstacles are in the way.

5. Measure the distance from the tree to the middle of the X on top of the stake. Round to the nearest 100th. Record this as MD (measured distance).

6. Plug the variables into the formula and do the math.

7. Compare the measured distance to the limiting distance. If the measured distance is bigger than the limiting distance, then the tree is OUT.

For check cruise purposes, it’s a good practice to record the azimuth, distance to, and species of any out trees.

Determining in/out trees on Variable Plots

Determining what trees to count on a variable plot requires using a relaskop. A relaskop projects an angle that is used to determine if a specific tree is large enough and close enough to the plot center to be counted under a certain Basil Area Factor (BAF).

Determining IN/OUT Trees with a Relaskop

• Stand with your eye directly over the plot stake.

• Look through the relaskop with it pointed at the tree.

• Use the brake button to adjust for slope.

• Line the side of the tree, at DBH, up with the edge of the first white bar.

• Look at the bar that represents the BAF you are working with.

• Is the tree smaller or larger than the bars that represent the BAF?

o Smaller not a measure tree, OUT o Larger measure tree, IN o Can’t tell Borderline Tree use the limiting distance formula

Examples: You are using a 20 BAF. A 20 BAF angle is represented by the first 3 bars (white, black, white). When the left side of the tree is lined up with the left side of the first white bar, the right side of the tree does not reach the extent of the second white bar. The tree is smaller than the 20 BAF angle and is OUT of the variable plot.

Use Symbols BAF Angles 0 -a 0-5 measures 5 BAF, 0-10 measures 10

BAF, 0-a measures 40 BAF

Measuring Diameter a – b Each bar represents a certain number of inches depending on how far away from the object you are

Measuring Heights T or P T is topo, used like a clinometer.

P is percent, used like a clinometer

You are using a 20 BAF. When the left side of the tree is lined up with the left side of the first white bar, the right side of the tree goes past the extent of the second white bar. The tree is larger than the 20 BAF angle and is IN the variable plot.

You are using a 20 BAF. When the left side of the tree is lined up with the left side of the first white bar, the right side of the tree lines perfectly with the right edge of the second white bar. This is a BORDERLINE tree. You will need to find the limiting distance and measure the distance with a tape.

Limiting Distance Formula for Variable Plots

Limiting Distance = (DBH) (Plot Radius Factor) (Slope Correction Factor)

Basal Area Factor Plot Radius Factor 10 2.708 20 1.902

Etc.… Etc.…

Steps to take:

1. Get DBH. Record

2. Take a slope measurement from the face of the tree at DBH to the top of the plot stake.

Record.

3. Insert nail on tape into the face of the tree facing plot center. Push it in hard, you don’t want it to pop out unexpectedly.

4. Pull tape to plot center. Make sure it is straight, despite what obstacles are in the way.

5. Measure the distance from the tree to the middle of the X on top of the stake. Round to nearest 100th. Record this as MD (measured distance).

6. Plug the variables into the formula and do the math.

7. Compare the measured distance to the limiting distance. If the measured distance is bigger than the limiting distance, then the tree is OUT.

Again, it’s a good practice to record the azimuth, distance to, and species of any out trees.

Cruising Parameters

For each cruise tree the: species, diameter, height, and seen defect will be measured and recorded.

Species

The species that we most commonly work with are: Ponderosa Pine, Lodgepole Pine, Douglas Fir, Grand Fir, Engelmann spruce, Wester Larch, and Subalpine Fir.

Measuring Diameters

Rules for taking DBH (Diameter @ Breast Height)

Diameters are taken at 4.5 ft from the ground on the uphill side of the tree.

When measuring 4.5 ft from the ground, follow the lean of the tree. A vertical distance of 4.5 ft may put your measurement too high on a tree with sweep. (The “4.5 ft.” line segments in the drawing are both 3 cm long)

Diameter tape should be perpendicular to the bole of the tree.

Round to the nearest 10th, always round down. Rounding down prevents a bias in favor of total timber volume and more accurately represents the diameter inside the bark.

If a tree forks at or above 4.5 feet, it is treated as one tree. If it forks below 4.5 feet, it is technically two separate trees.

Common Potential Problems When Taking DBH

• Obstacles (large rocks, logs, etc.) keeping you from measuring 4.5 feet from the ground on the uphill side.

If you can, move the obstacle or work around it. If you can’t use those options, measure from the top of the obstacle and note it in your cruise notes.

• Trees growing on top of objects or in eroded areas.

Measure diameter at 4.5 ft from the top of the root crown. Note it in your cruise notes.

• Obstacles (large branches, swell, burl, etc.) in the bole at DBH

Take DBH right above the obstacle. If that’s not possible, take it below. Note where you took DBH and why.

You can also take a diameter at equal distances from 4.5 ft above and below the abnormality and average those measurements. Always note what you did.

Measuring Tree Heights

When measuring tree heights, we measure from the very top of the tree to where the trunk meets the ground. Other than species type and tree count, height measurements have the biggest effect on the cruise results.

Rules for Taking Tree Heights

Cruiser should be at least as far away from the tree as the tree is tall.

This allows the cruiser to get a full view of the tree and ensures higher accuracy.

Always take height measurements from a location that puts you at a right angle to the lean of a tree.

If the tree is leaning directly toward or away from you, it will appear taller or shorter than it actually is.

Measure from the very top of the tree to where the stem meets the ground on the uphill side.

Round to the nearest foot with normal rounding rules.

Correct for slope when using a clinometer or a relaskop.

Refer to the Clinometer, and Relaskop documents found in the Training Packet for clinometer and relaskop use.

Refer to the Clinometer document for a slope correction example.

Common Potential Problems When Taking Heights

• Forked Tree

Measure to the tallest fork. Unless the fork starts below 4.5 feet and it’s technically 2 trees.

• Broken top

Find the top and measure it with a logger’s tape. Add its length to the measured height of what is standing. Make a note.

If you can’t find the top, estimate the total tree height by averaging the heights of 3 similar trees in the same area. Make a note.

• Leaning trees

Lean less than 25% being at right angles to the lean should provide an accurate measurement. (Refer to Clinometer document to learn how to determine the percent lean.)

Lean more than 25% You must actively utilize Pythagorean theorem.

1. Use a logger’s tape to measure the length from the base of the tree to the point on the ground directly under the tip of the tree (a).

2. Use a laser hypsometer, clinometer, or relaskop to measure the distance from the tree tip to the ground directly under the tip (b). Do this just as you would measure a tree height.

3. Use a² + b² = c² to obtain the length of c. c = the length of the leaning tree.

Example: a = 22 ft, b = 88 ft c² = 22² + 88² c² = 484 + 7,744 c² = 8228 c = 90.7 round to 91……The tree is 91 ft tall

• Can’t see the bottom of the tree from the point of measurement due to brush or topography

Mark a known height on the tree with some flagging or a hanging reflector. Measure from the tree’s top to the mark. Add the known height to the measured tree height.

Slope Correction

Many cruise techniques and formulas use the horizontal distance between the cruiser and the object in question. Whenever the taped distance between the cruiser and the object in question has a slope greater than 10% a slope correction must be made. This requires multiplying the distance by a correction factor.

Percent Slope

Correction Factor

Percent Slope

Correction Factor

0-10 1 56-57 1.15 11-17 1.01 58-59 1.16 18-22 1.02 60-61 1.17 23-26 1.03 62-63 1.18 27-30 1.04 64-65 1.19 31-33 1.05 66-67 1.2 34-36 1.06 68-69 1.21 37-39 1.07 70 1.22 40-42 1.08 71-72 1.23 43-44 1.09 73-74 1.24 45-47 1.1 75 1.25 48-49 1.11 76-77 1.26

Seen Defect

We record what percentage of the tree is affected by defects that we can detect with our eye. Some common defects include: Sweep, crooks, forks, frost cracks, cat faces/fire scars, lightening scars, and conks.

Cruisers will deduct lengths from each log with defect in it. These deductions are referred to as “cuts”.

Determining defect can be subjective, two cruisers may take different cuts and come to a similar percentage of total defect. When taking defect notes, be sure to record which log(s) the defect is in.

Calculating the Percentage of Seen Defect

We only count defect above the 1 ft stump and below the merchantable height. Indicators of rot and any physical characteristics that will make that piece of the tree unusable will be accounted for. Specific rules associated with specific types of defects will be covered at the regional cruise training.

Cuts

To calculate the percentage of defect, you will mentally cut out the unusable sections of each log. We work with whole 1 ft cuts or “pie cuts”.

Pie cuts are used for defect that doesn’t affect the whole circumference of the tree. For example, a four-foot frost crack may only affect a quarter of the circumference of the tree. Apply a ¼ pie cut of four feet to get a 1-foot cut. A weeping four-foot frost crack may affect half of the tree’s circumference, so apply a ½ pie cut of four feet to get a 2-foot cut.

Logs

We keep track of what log the defect is in because each log of a tree contains a different percentage of the tree’s total volume. The bottom log, being the fattest log, accounts for the highest percentage. The top log, being the skinniest, accounts for the lowest percentage. One log is 16 feet with .5 feet of trim on both ends. For defecting purposes, the top of the first log is 17 feet high.

Percent Defect Table

The yellow cells are referring to what percentage of the tree’s volume is represented by that specific log, or 1 foot of that specific log. For example, the entire 2nd log of a 6-log tree is 22% of the tree’s volume. 1 foot of the 2nd log of a 6-log tree is 1.4% of the tree’s volume.

The yellow column on the left is referring to the location of the merchantable height. The yellow column on the right is referring to the number of logs in a tree with that merchantable height. For example, If the merchantable height is between 59 and 75 feet, then it is a 4-log tree.

1 2 3 4 5 6 7 8 9 10 Max. Ht. 17 34 50 67 83 100 116 133 149 166

1--25 1 100/6.3 26--42 2 63/3.9 37/2.3 43--58 3 45/2.8 33/2.1 22/1.4 59--75 4 37/2.3 28/1.8 21/1.3 14/0.9 76--91 5 32/2.0 25/1.6 19/1.2 15/0.9 9/0.6 92--108 6 27/1.7 22/1.4 19/1.2 14/0.9 11/0.7 7/0.4

109--124 7 24/1.5 21/1.3 19/1.2 17/1.1 11/0.7 5/0.3 3/0.2 125--141 8 22/1.4 19/1.2 17/1.1 15/0.9 11/0.7 8/0.5 5/0.3 3/0.2 142--157 9 20/1.3 16/1.0 14/0.9 13/0.8 12/0.8 10/0.6 7/0.4 5/0.3 3/0.2 158--174 10 19/1.2 16/1.0 14/0.9 13/0.8 12/0.8 10/0.6 7/0.4 5/0.3 3/0.2 2/0.1

VISIBLE DEFECT GUIDE-6 INCH TOP DIAMETER

Merch.

Height

Number of Logs

Log Tops - 16.5 Feet + 1 Foot Stump

1 2 3 4 5 6 7 8 9 10 Max. Ht. 17 34 50 67 83 100 116 133 149 166

1--25 1 100/6.3 26--42 2 63/3.9 37/2.3 43--58 3 45/2.8 33/2.1 22/1.4 59--75 4 37/2.3 28/1.8 21/1.3 14/0.9 76--91 5 32/2.0 25/1.6 19/1.2 15/0.9 9/0.6 92--108 6 27/1.7 22/1.4 19/1.2 14/0.9 11/0.7 7/0.4

109--124 7 24/1.5 21/1.3 19/1.2 17/1.1 11/0.7 5/0.3 3/0.2 125--141 8 22/1.4 19/1.2 17/1.1 15/0.9 11/0.7 8/0.5 5/0.3 3/0.2 142--157 9 20/1.3 16/1.0 14/0.9 13/0.8 12/0.8 10/0.6 7/0.4 5/0.3 3/0.2 158--174 10 19/1.2 16/1.0 14/0.9 13/0.8 12/0.8 10/0.6 7/0.4 5/0.3 3/0.2 2/0.1

VISIBLE DEFECT GUIDE-6 INCH TOP DIAMETER

Merch.

Height

Number of Logs

Log Tops - 16.5 Feet + 1 Foot Stump

The yellow row gives the top height for each log. Example: The top of the 3rd log is at 50 feet. The top of the 9th log is 149 feet.

Overall Defect Example

You have a ponderosa pine with a typical fork located at 37 ft. You have estimated the merchantable height to be at 72 ft.

With a merchantable height of 72 ft, it is a 4-log tree.

The table tells us that the top of the 2nd log is at 34 ft. and the top of the 3rd log is at 50 ft., so we know that the fork is located within the 3rd log.

The table states that 1 foot located in the 3rd log of a 4-log tree is 1.3% of the tree.

Standard cut for a typical fork is 2 feet.

2 x 1.3 = 2.6 total defect

Round with normal rounding rules to 3% total defect

1 2 3 4 5 6 7 8 9 10 Max. Ht. 17 34 50 67 83 100 116 133 149 166

1--25 1 100/6.3 26--42 2 63/3.9 37/2.3 43--58 3 45/2.8 33/2.1 22/1.4 59--75 4 37/2.3 28/1.8 21/1.3 14/0.9 76--91 5 32/2.0 25/1.6 19/1.2 15/0.9 9/0.6 92--108 6 27/1.7 22/1.4 19/1.2 14/0.9 11/0.7 7/0.4

109--124 7 24/1.5 21/1.3 19/1.2 17/1.1 11/0.7 5/0.3 3/0.2 125--141 8 22/1.4 19/1.2 17/1.1 15/0.9 11/0.7 8/0.5 5/0.3 3/0.2 142--157 9 20/1.3 16/1.0 14/0.9 13/0.8 12/0.8 10/0.6 7/0.4 5/0.3 3/0.2 158--174 10 19/1.2 16/1.0 14/0.9 13/0.8 12/0.8 10/0.6 7/0.4 5/0.3 3/0.2 2/0.1

VISIBLE DEFECT GUIDE-6 INCH TOP DIAMETER

Merch.

Height

Number of Logs

Log Tops - 16.5 Feet + 1 Foot Stump

1 2 3 4 5 6 7 8 9 10 Max. Ht. 17 34 50 67 83 100 116 133 149 166

1--25 1 100/6.3 26--42 2 63/3.9 37/2.3 43--58 3 45/2.8 33/2.1 22/1.4 59--75 4 37/2.3 28/1.8 21/1.3 14/0.9 76--91 5 32/2.0 25/1.6 19/1.2 15/0.9 9/0.6 92--108 6 27/1.7 22/1.4 19/1.2 14/0.9 11/0.7 7/0.4

109--124 7 24/1.5 21/1.3 19/1.2 17/1.1 11/0.7 5/0.3 3/0.2 125--141 8 22/1.4 19/1.2 17/1.1 15/0.9 11/0.7 8/0.5 5/0.3 3/0.2 142--157 9 20/1.3 16/1.0 14/0.9 13/0.8 12/0.8 10/0.6 7/0.4 5/0.3 3/0.2 158--174 10 19/1.2 16/1.0 14/0.9 13/0.8 12/0.8 10/0.6 7/0.4 5/0.3 3/0.2 2/0.1

VISIBLE DEFECT GUIDE-6 INCH TOP DIAMETER

Merch.

Height

Number of Logs

Log Tops - 16.5 Feet + 1 Foot Stump

Figure 1 Crook Figure 1: Crook Figure 2: Sweep Figure 3: Fire Scar

Figure 4: Frost Crack with Associated Rot Figure 5: Indian Paint Conk Figure 6: Fork