1. Measuring Trees
Part 2 - Height

2. - an instrument for measuring heights (of trees)
Hypsometer
- an instrument for measuring heights (of trees)

3. Tree Heights
Total height = height (or stem length) from ground line to top of terminal bud.
Merchantable height = stem length (or height) from assumed stump height to an arbitrary, fixed upper-stem diameter (ib or ob)

4. Scales of Measure
Degree – reads angle from horizontal for trigonometric calculations
Percentage – reads directly in feet of height at 100 feet distance (rise/run) (45 degrees equals 100 percent slope)
Topographic – reads directly in feet of height at 66 feet (1 chain or 20 meters) away
This is where your pacing or hipchain really comes in handy

5. Trigonometry of right triangles
a = b(tan A)

6. Measuring Height with degrees

7. Measuring Standing Tree Height
Percentage Scale
Percent slope =
(rise / run) x 100
If distance from tree (D), or
"run" is 100 feet,
The reading from horizontal
to Stump height (A) is 5 feet
and tree height above
the horizontal plane (B) or
"rise" is 80 feet
Total Tree height equals A + B = 85 feet

8. General Formula H = (HT - HB)*(HD/BD) HT = Height to top (BA)
HB = Height to Base (BC)
Reading will be negative
(unless tree above you)
HD = Horizontal Distance
From person to tree
BD = Base Distance
66 (for topographic scale)
Or 100 (for percent scale)
If you are at scale distance,
This factor (HD/BD) equals 1
and can be ignored

9. Sloping Plots

10. Trigonometry of slope correction

11. Slope Correction

12. Slope Correction Desired horizontal distance to the tree = 100 feet
Slope to the tree = 32% (slope correction needed)
Slope correction factor = 1.05
Taped distance to the tree = 100 feet * 1.05 = 105 feet
The measuring instrument is moved to a taped distance of 105 feet
Angle to tree base = 4%; Angle to tree top = 76%
Tree height = 76 feet - 4 feet = 72 feet

13. Tree Heights
Measuring Tools

14. Abney Level

15. Blume-Leiss Altimeter

16. Haga Altimeter

17. Laser Hypsometers
Line of site limitations, expensive

18. Measuring Rod

19. Merritt Hypsometer

20. Merritt Hypsometer – Make your own

21. Look Ma! - No Tools

22. Suunto Clinometer
Degree and Topographic Scales

23. Suunto Clinometer
Degree and Percent Scale

24. Clinometer on the cheap

25. Clinometer Toys

26. Spiegel Relaskop

27. Tree Height Left scale in percent at 100 feet.
What is the tree height?

28. Upper Stem Diameter
Compensates for angle

29. Ultrasonic
Not Limited by Line of Sight like Laser or Optical

30. Apps

31. iHypsometer Lite

32. Merchantable height
A normal trees’ merchantability stops at the narrowest diameter that the lumber mill can handle
This is usually 4 to 6 inches

33. Vertical Limits to Merchantability
Stoppers are occurrences in the tree that can not be productively sawn through and limit the length of a potential log section.
Forks that are at least 1/3 diameter of main bole at point of occurrence and 45 degrees or less in angle from the main bole.
Branches, stubs, remnant bumps. – ½ diameter of main stem.
Any embedded metal excluding aluminum.
Sudden dramatic change in bole diameter

34. Measuring Tree Heights
Problem Trees

35. Leaning Trees
Measure perpendicular to the lean, angling your hypsometer (reads normally)

36. Measured from the direction of the lean
Can use Pythagorean Theorem to solve

37. Conversely You measure B normally (not full tree height)
To get true bole length (A), you need angle C also
Then A = B/cos C

38. Avoid this mistake

39. Irregular Stems

40. Broken Tree Measure height of the stub
Measure length of the piece on the ground (trigonometry may be needed)
Add the two measurements to obtain total height

41. Recap and Questions