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Measuring Trees

Measuring Trees. Part 2 - Height. Hypsometer. - an instrument for measuring heights (of trees). Tree Heights. Total height = height (or stem length) from ground line to top of terminal bud .

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Measuring Trees

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  1. Measuring Trees Part 2 - Height

  2. 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 This is where your pacing or hipchain really comes in handy 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

  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. Slope Correction

  11. 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

  12. Tree Heights Measuring Tools

  13. Abney Level

  14. Blume-Leiss Altimeter

  15. Haga Altimeter

  16. Laser Hypsometers Line of site limitations, expensive

  17. Measuring Rod

  18. Merritt Hypsometer

  19. Merritt Hypsometer – Make your own

  20. Look Ma! - No Tools

  21. Suunto Clinometer Degree and Topographic Scales

  22. Suunto Clinometer Degree and Percent Scale

  23. Clinometer on the cheap

  24. Clinometer Toys

  25. Spiegel Relaskop

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

  27. Upper Stem Diameter Compensates for angle

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

  29. Apps

  30. iHypsometer Lite

  31. Measuring Tree Heights Problem Trees

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

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

  34. 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

  35. Avoid this mistake

  36. Irregular Stems

  37. 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

  38. Recap and Questions

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