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2102 Exam 1 pt 2
Measuring standing trees
| Question | Answer |
|---|---|
| 1. What is dbh? Where do we measure dbh? Why at that point? | Diameter at breast height. Measure at breast height (4.5ft). B/c standard height, and often free of butt swells. |
| 2. One-inch diameter classes: The 10” class spans from ____ inches to ____ inches. | 9.51" to 10.5" |
| 3. Two-inch diameter classes: The 10” class spans from ____ inches to ____ inches. | 9.01" to 11.0" |
| 4. A forester measured a tree dbh as 12 inches. Can you guess whether he was using 1-inch or 2-inch dbh classes? Explain. | A forester could be using either a 1" or a 2" class if he has a dbh of 12 inches because the dbh is even so both classes apply. |
| 5. What does D-tape really measure? | D- Tape measures circumference C = πD ==> every 3.14" on D-Tape = 1 inch of diameter overestimate: always positively biased |
| 6. For D-tapes: Is a 1-inch interval between 7 and 8 inches of the same distance as another 1-inch interval between 12 and 13 inches? Explain why. | Yes because even though they have different decimal points they are still in 1" class therefore they both measure the same distance. |
| 7. For Biltmore sticks: Is a 1-inch interval between 7 and 8 inches of the same distance as another 1-inch interval between 12 and 13 inches? Explain why. | Graduation formula: G = D / Sqrt( 1+ D/A ) where D = dbh, A = distance from eyes, G = distance on stick (all in the same unit) as the numbers get bigger the distance gets smaller |
| 8. I measured diameter of a tree using two different instruments and obtained readings of 12.3” and 12.5”. Which reading belonged to the D-tape and which belonged to the calipers? Why? | The 12.5 belongs to the D- Tape because there is almost always overestimating unless the tree is a perfect circle. Whereas the calipers take 2 perpendicular measurements and then average between the 2 making the measurement slightly less than the D-Tape. |
| 9. How do you measure DBH in the following unusual situations:(a) sloping ground, (b) leaning tree, (c) forking tree (2 cases), and (d) butt swell (2 cases). | A) measure DBH uphill B) measure perpendicular to the lean C) measure DBH at 4.5 as normal if fork is above 4.5' If below 4.5' then measure as 2 trees 3.5' above the fork D) If buttswelll is <3' you measure 4.5 as normal If > 3' you go 1.5' above swell |
| 10. Compute dib of a tree, given that its dob is 17.5” and single bark thickness is 0.4”. | dib = dob - double bark thickness 17.5" - 0.4" = 17.1" dib |
| 11. What do you call instruments that measure tree diameters? List all of these instruments that we cover in this course. | (Dendrometers) D- Tape Calipers Biltmore Stick |
| 12. What do you call instruments that measure tree heights? List all of these instruments that we cover in this course. | (Hypsometers) Haga Altimeter Abney Hand Level Suunto Clinometer |
| 13. Suppose you used a Suunto clinometer with percent scale to measure total height from a 60-foot distance, and the readings were +5 and +92, what was the total height? Draw a simple diagram to illustrate your logic. | 92-5=87ft x/87=90/66 52.2= 52ft |
| 14. Suppose you used a Haga altimeter with topographic scale to measure total height from a 90- foot distance, and the readings were -4 and +89, what was the total height? Draw a simple diagram to illustrate your logic. | 4+89=93ft x/93=90/66 126.8= 127ft |
| 15. How far should you be from a tree in order to measure its height? | 100ft |
| 16. What are convenient distances for hypsometers with percent scales? | 100' Convenient distances: 33', 50', 66', 100', 132' |
| 17. What are convenient distances for hypsometers with topographic scales? | 66' Convenient distances: 33', 50', 66', 100', 132' |
| 18. Name all possible scales for a device that measure tree heights. What do you call that device? List all brand names that we cover in this course. | % scale and topographic, tree height scale haga altimeter, abney hand level, suunto clinometer, merrette hypsometer |
| 19. How would you measure tree height of a leaning tree? | You would measure the tree height perpendicular to the lean because this leaves less room for error |
| 20. Define Girard form class. | Girard form class = 100 (dib@17.3' / dbh) 17.3' = 16' log + 1' stump + 0.3' trim allowance Reason: (DBH) (FC) = scaling diameter of the first log |
| 21. If a tree measured 14.2” in dbh, 12.5” at 17.3’, and 0.3” in single bark thickness, compute Girard form class for that tree. | 100 x (0.6" / 14.2) = 4.2 |
| 22. Assuming that the average Girard form class for a particular stand is 80. What is the approximate scaling diameter of the butt log of a tree measuring 13.2"”in dbh. | 80=100(x/13.2) x=10.56ft |
| 23. List all the steps involved in measuring Girard form class. | measure dbh, then what number is at 17.3' and then if its double or single bark thickness |
| 24. A ring count at breast height reveals 15 rings (a ring consists of both springwood and summerwood). How old is the tree? | 15yrs but give or take 5-3 years if its a pine or slow growing tree |
| 25. What instrument do you need to measure slope percent? List all the steps you need to take. | use a suunto clinometer, 100ft distance, measure bottom of the tree, measure top of tree, then average numbers. |
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MaddieAlexE
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