Clinometer
-Suunto Optical Reading Precision InstrumentsModel PM-5
Purpose: A clinometer is a measuring device used to measure the angle of a line of sight above or below
horizontal to determine height, slope and vertical angles. They are used by forestry workers to measure the
height of trees or calculate the slope of a hillside.
Directions for Determining Height Using Percent Scale: To acquire height measurements
with a clinometer, hook the logger tape to the tree to be measured and walk away from it, measuring your
distance traveled. Walk far enough away so that you are standing where you can see both the top and bottom
of the tree. Hold the clinometer up to your eye and look through the black eyepiece so that the glass window
on the side is to the left. Remember to keep both eyes open when looking through a clinometer. One eye should
look at the tree you are measuring and the other should be looking through the eyepiece and reading the
numbers on the right hand side of the scale inside. From here, sight the top of the tree for the top % reading and
the bottom of the tree for the bottom % reading. The % scale is on the right hand side inside the clinometer.
Then follow this simple mathematical formula to calculate the height:
% to top - % to bottom = total % height
then
total % height x horizontal baseline distance (feet) = height
Height measurements on level ground and above a tree: (Figure 1)
Using the percent scale (right side scale) and horizontal baseline distance convenient for you to see both the
top and bottom of the tree, back away from the tree and measure the baseline distance. In this example, 80 feet.
Sight the top of the tree and read the % scale, the right column of the scale inside the clinometer (63%). Sight
the bottom of the tree and read the % scale (-7%). Subtract the bottom reading from the top reading: 63% -(7%) = 70%. To obtain tree height, simply multiply this percentage times your horizontal baseline distance. 70%
x 80’ = 56’ tree height. See Figure 1.
Height measurements on sloping ground and below the tree: (Figure 2)
When the base of the tree is ABOVE eye level, sight the top then sight the base. Subtract the base reading from
the top reading. This example: 70% - 14% = 56%. Then multiply 56% x 100’ = 56’ (tree height). See Figure 2.
When the base of the tree is BELOW eye level, sight the top then sight the base. Subtract the bottom reading
from the top reading. For example, -10% top reading - (-66% bottom reading) = 56%. Then multiply by 100’
(baseline) for a tree height of 56’.
Care for Instrument: Store in case when not in use. Use lanyard to secure to neck.
Logger Tape
-Spencer Original Logger Tape 75 feet Model 975-C
Purpose:
A logger tape is used to measure the length of logs or the diameter of tress. The end has a special hook or nail
that holds the end of the tape at the end of the log or into the tree, but the hook releases when jerked; then the
tape will automatically rewind. Logger tapes can measure the diameter and circumference or a tree! Logger
tapes can also be used with clinometers to measure the height of trees.
Directions for Use:
One side of the logger tape can measure the distance around the tree (circumference), and the other side is a
diameter tape which is calibrated in increments of pi. The pi increments convert the measurement from
circumference to diameter for the forester automatically.
This logger tape is calibrated in increments of inches and feet on the one side that is used for measuring
distance from or around a tree. The other side, the diameter equivalents of circumference, is calibrated in pi and
tenths of pi and is used for measuring tree diameter.
The Horseshoe Nail Hook: The tape comes with a loop riveted to the end of it and with a hook attached to
the loop. Naturally the hook takes a lot of abuse, so it is critical to keep the horseshoe nail with the tape at all
times to help make it last. The nail is used to attach your tape to the bark of the tree that you are measuring.
This will hold the tape securely so that you can walk away from the tree and measure distance.
Care for Equipment:
Make a habit to always stop the tape with your fingers when reeling it in, and keep the tape tight on the spool.
Keep the tape clean to guard against kinking. Do not let the tape rewind uncontrolled.
The spring tension is factory set so the tape cannot be pulled out past the final foot mark plus two inches. Do
not force the tape and do not adjust the tension.
Increment Borer
-Suunto Increment Borer 16”-
Purpose:
An increment borer is like a hollow auger that is used to determine the age of a tree by extracting
a small dowel-like piece from a tree. From this we can learn about growth, tree health, climate, wood decay, or
the penetration of preservatives in timbers. Data regarding age and rate of growth is critical in making forest
management decisions.
The orange handle is hollow, and the drill bit and extractor can be stored inside the handle when not in use.
The extractor is a long half moon shaped blade that slips inside the hollow auger and allows you to pull out
(extract) the core sample.
Directions for Use:
WARNING: The end of the borer bit is very sharp. Handle with care. If you are boring several trees, it is
useful to wear gloves to prevent blisters from forming in the palm of your hands.
Separate the handle from the borer bit and extractor. Place the extractor in a convenient place, to prevent
damage to the extractor. Please care for the extractor. It is thin and can bend easily. Once bent, it is useless and
must be replaced! Assemble the handle and borer bit by pushing the locking latch away from the handle with
your thumb.
NOTE: Before boring a tree, apply beeswax to the threads and shank of the borer bit. This will make
penetration and removal of the bit easier. Never bore into a leaning tree. Leaning trees contain tension
and compression wood that could cause the bit to become locked in the tree.
Then insert the square end of the borer bit into the handle, and return the locking latch completely around the
borer bit "collar". The goal is to bore directly into the pith, or the center of the tree. Align the borer bit and
handle so that the bit will penetrate toward the center of the tree at a right angle. In any other alignment, the
annual growth rings seen in the extracted core will be distorted and could result in erroneous growth rate
analysis. Place the borer bit threads against the uphill side of the tree at 4.5 ft above the ground. This should be
done in a fissure or crack, where the bark is thinnest. Hold the bit near the threads with one hand; with your
other hand push forward on the handle while simultaneously turning it clockwise until the threads penetrate
the wood enough to hold the bit firmly in place. Place both hands, palms open, on the ends of the handle and
turn clockwise until the bit reaches the approximate center of the tree. With the bit at the desired depth,
insert the full length of the extractor concave side down. Then turn the handle one-half turn counter-clockwise
to break the core from the tree and to turn the extractor concave side up. Pull the extractor from the borer bit.
The core will be resting in the channel and held in place by the small teeth at the tip of the extractor. If the
borer is left in the tree for an extended period of time, it can become stuck. Before examining the core
sample, promptly remove the borer bit from the tree by turning the handle counter-clockwise. In order to
prevent insect damage; replace the wood core into the tree once measurements and ring counts have been made.
Care for Equipment: Use the included wooden dowel to remove broken core pieces from the borer. Do
not use metal objects such as nails to remove lodged cores! When finished using the borer use a WD-40 soaked
cloth to remove resins from the bit to help prevent rusting.
Compass
-Variety of models-
Purpose:
A compass is a basic navigational tool that uses the earth’s magnetic fields to determine direction.
Directions for Use:
The red and black arrow is called the compass needle. On some compasses it might
be red and white, but the point is, the red part of it is always pointing towards the earth's magnetic north pole.
That's basically how the compass works.
Using the compass to move directions other than north. The turnable dial on your compass is called the
azimuth ring. On the edge of the compass housing, there will be a scale from 0 to 360. Those are the degrees or
the azimuth (or you may also call it the bearing in some contexts). And you should have the letters N, S, W and
E for North, South, West and East. If you want to go in a direction between two of these, you would combine
them. If you would like to go in a direction just between North and West, you simply sa
say:
y: "I would like to go
Northwest.”” Then find out where the compass housing “Northwest” is, and turn the compass housing so that
northwest on the housing comes exactly where the large direction of
travel-arrow meets the housing.
Using the compass to take
ake bearings
bearings. A bearing is a horizontal angle
measured clockwise from north (either magnetic north or true north) to
some point (either a point on a map or a point in the real world).
Bearings are used to accurately travel to a destination or to locate yo
your
position. If you are working from your map, it is called a map bearing and the angle you are measuring is the
angle measured clockwise from true north on your map to this other point on the map. If you are taking a
bearing off a real point on the landscape
ape with a compass, you are using your compass to measure the angle
clockwise from magnetic north to this point on the landscape. This is called a magnetic bearing. Remember
that the bearing is measured clockwise. If you think of true north as 12 o'clock tthen
hen a bearing to the right of
that (1 o'clock) is greater than true north and a bearing to the left of True north (11 o'clock) is less than true
north.
Basal Area Angle Gauge
-Panama-
Purpose: Basal area angle gauges are used to measure the basal area of the trees
occurring at a point or "plot" center. Basal area is the area of the cross-section of tree
stems near their base, generally at breast height, and including bark measured over 1 acre
of land. This basal area (BA) is then used to calculate the volume of a tree. Basal area increases as stand size
and site quality increases.
What is Basal Area? If you cut a tree off at breast height and measure the surface area of the stump, you would
have the basal area (BA) of the tree. This measurement is used to describe the amount of space in a given area
that is being occupied by tree stems or stumpage.
The greater the stand's basal area, the greater the portion of land that is occupied by tree stems. Basal area does
not indicate tree diameter. However, it is a measure that describes the density of your woodlot. For example, a
hard maple stand with a basal area of 21 m2 may have 467 24-cm trees, while an adjacent stand with the same
basal area may have 167 40-cm trees. Most woodlots will contain a mixture of all diameter size classes.
Basal area is measured at breast height (DBH) 1.3 m above the ground and is commonly expressed in square
meters or square feet on a unit basis - generally on a per hectare or acre basis. The formulas to calculate the
basal area of an individual tree or a stand of trees in square meters are as follows:
Basal area of a tree = the diameter of the tree (cm) squared, times 0.00007854. Expressed in square meters. For
example, the basal area of a 30-cm tree is 0.070686 m2.
Basal area of a stand of trees = the sum of all the individual tree basal areas for a given land area. Expressed in
square meters. For example, if the woodlot contains 325 30-cm trees per hectare, the basal area would be 23 m2.
Stand BA = 325 trees/ha x 0.070686 = 23 m2
Directions for Use: To use the angle gauge, find a fixed spot in the center of your plot. While standing
over a single point facing North, hold the gauge up to your eye and look at each nearby tree as you rotate
clockwise in a full circle. Don't miss any trees as you turn. Focus on each tree at breast height, 4 1/2 feet above
ground. If the stem of any tree is wider than your target - sticks out into the arms of the “T”, for example -count the tree (see Figure 1). You don't have to measure anything, just count trees. When you've completed a
360-degree circle about the point, multiply the count by 10. The result is one estimate of basal area per acre.
You should repeat this several times throughout your woodlot and average the results.
Figure 1: Which trees to count.
Forest Densiometer
-Concave Model C-
Purpose: Use to determine forest overstory density or percent canopy cover. Helpful when establishing
spacing standards in forest thinning and determining light requirements for regeneration. Also good for use in
riparian assessments to see how much of an area is shaded.
Directions for Use: The densiometer is a convex mirror with a grid etched into it. There are 24 squares
in the mirror. Imagine 4 uniformly spaced dots (96 total) in each square of the grid, as illustrated (see figure,
below), and calculate the number not covered by vegetation. When percent canopy cover is high, it is easier to
count dots not covered and subtract the total from 96. When canopy cover is low, it is quicker to count
covered dots and record that number. Always record number of dots uncovered by canopy.
Do not break the squares into 4 imaginary squares and try to decide if each one has greater or less than 50%
cover. The 4 squares within a square method introduces bias because individuals tend to decide close calls
more frequently in one direction than another. Deciding whether or not an imaginary dot is covered is a simple
objective decision, and is less susceptible to bias. Avoid counting trunks as cover when possible, particularly
when they make up a substantial portion of the cover. Step away from the trunk if necessary.
FOR FIELD USE: Once the representative forest site has been selected for measurement, the user holds the
instrument level and far enough away from his or her body such that the operator’s head is just outside the grid,
usually 12-18 inches away at elbow height. Have the lid open as far as it will go facing away from the operator.
Count the number of dots uncovered. Once the operator has counted the number of dots that are uncovered, up
to 96, the number determined is then multiplied by 1.04 to obtain the percent overhead NOT occupied by
canopy. The difference between this percentage and 100% is the estimated overstory density in percent.
Percent Canopy Cover = 100% - (number of dots uncovered out of 96 x 1.04)
To get accurate numbers, four readings should be taken at a reference site, one facing North, South, East, and
West. These four numbers should then be averaged to maintain accuracy.
Forest
Monitoring
Kit
Instructions
Klamath Basin Research and Extension Center
Klamath County Extension
3328 Vandenberg Road
Klamath Falls
Falls, OR 97603
(541)-883-7131