Difference between revisions of "AY Honors/Forestry/Answer Key"

Revision as of 11:32, 13 April 2008

A Diameter Tape(D-Tape)is a form of dendrometer that consists of a cloth or metal tape that is mainly used to measure diameter at breast height (DBH). DBH is measured at a fixed height of 4.5 feet (137.16 cm), where it is easiest for most people to measure diameter. DBH is measured up high so to avoid measuring a trees' butt swell. Butt swell is where the base of the tree is unconventionally fatter then the rest of the tree. height and diameter are used to determine the volume of a given tree, measuring above the butt swell is required to provide the most accurate measurement.^&

Picture of a Spencer Right Handed Logging Tape

Diameter is easily measured because the tape is calibrated in units of 3.14(pi) inches or centimeters. The tape is actually measuring the trees circumference but since circumference and diameter are related by pi, the diameter can easily be obtained.The only problem with the D-tape is that the measurements assume the tree's trunk cross-sections are perfectly circular.Thus the D-tape just gives an approximation, but this approximation is the easiest and most commonly used dendrometer for DBH.^&

Measuring Diameter

To calculate the diameter of a tree, wrap the tape(diameter side facing user) around the tree at 4.5 feet (137.16 cm) above ground. Where the number "0" aligns with the rest of the tape, this is the diameter of the tree.

This shows Brandon measuring the trees DBH at 4.5 feet above ground. He is making sure that the tape is perfectly level and that the tape is not kinked, so as not to mess up the reading of the diameter

File:Measuring dbh.JPG

Thus this tree has a diameter of 16 inches (40.64 cm).

References

↑ http://www.cnr.vt.edu/dendro/forsite/dtape.htmAs
↑ Moran,L.A, and R.A Williams.2002. Comparison of three dendrometers in measuring diameter at breast height. Northern Journal of Applied Forestry 19:28-33.

[1] ttp://www.cnr.vt.edu/dendro/forsite/dtape.htmAs

[2] Moran,L.A, and R.A Williams.2002. Comparison of three dendrometers in measuring diameter at breast height. Northern Journal of Applied Forestry 19:28-33.

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-{{confusing|date=March 2008}}
+{{Expand|date=March 2008}}
-{{internallinks|date=March 2008}}
-{{refimprove|date=March 2008}}
-{{wikify|date=March 2008}}
-The '''clinometer''' is a common tool used in [[forestry]] to measure [[slope]], [[vertical (angles)]], and -incombiation with range measurements- evlevation heights.
+A '''Diameter Tape'''(D-Tape)is a form of [[dendrometer]] that consists of a cloth or metal tape that is mainly used to measure [[diameter at breast height]] (DBH). DBH is measured at a fixed height of 4.5 feet (137.16 cm), where it is easiest for most people to measure [[diameter]]. DBH is measured up high so to avoid measuring a trees' butt swell. Butt swell is where the base of the tree is unconventionally fatter then the rest of the tree. height and diameter are used to determine the volume of a given tree, measuring above the butt swell is required to provide the most accurate measurement.<ref> http://www.cnr.vt.edu/dendro/forsite/dtape.htmAs</ref>
-==How It works==
+[[Image:DTape Picture.JPG|thumb|left|200px|Picture of a Spencer Right Handed Logging Tape]]
-Clinometers, known in many fields as an "[[inclinometer]]", make use of basic trigonometric principles. Multiplying the distance (D) between the observer and an object times the [[tangents]] of the angles to the base and to the top of the object, and then adding them together gives the observer the total height of the object.<ref>[http://mysite.du.edu/~jcalvert/astro/abney.htm Calvert, J.B. “The Clinometer.” 2003.]</ref>
-[[Image:Illustration of the basic trigonometric principles used by a clinometer.JPG|right|thumb]]
-==Usage==
+Diameter is easily measured because the tape is calibrated in units of 3.14(pi) inches or centimeters. The tape is actually measuring the trees circumference but since circumference and diameter are related by pi, the diameter can easily be obtained.The only problem with the D-tape is that the measurements assume the tree's trunk cross-sections are perfectly circular.Thus the D-tape just gives an approximation, but this approximation is the easiest and most commonly used dendrometer for DBH.<ref>Moran,L.A, and R.A Williams.2002. Comparison of three dendrometers in measuring diameter at breast height. Northern Journal of Applied Forestry 19:28-33.</ref>
-The [[forester]] stands at a fixed distance from the base of the [[tree]]. The most common distances in the [[United States]] are 50, 66, and 100 feet. To obtain accurate readings it is best to use taped measured distance instead of pacing distances. For the most accurate readings it is best to use a distance that is equal to or greater than the height of the tree you are measuring.<ref> Avery, T.E. and Burkhart, H.E. “Height Measurement Principles.” Forest
-Measurements 5th Edition. McGraw-Hill, 2002. 154.</ref> The observer then sites to the top of tree, if total height is the desired measurement. If merchantable height is the desried measurement the observer sites to a point on the tree where no more merchantable timber can be used. The observer then measures to the bottom of the tree and adds the two figures together. This will be the height of the tree. Always measure a leaning tree so that the tree is leaning to the left or right. Measurements should never be taken with the tree leaning toward or away from the observer because this will affect the [[accuracy]] of the measurement. The clinometer is also commonly used by foresters to obtain the percent slope of terrain. This measurement is based on the same trigonometric principles described above.
-[[Image:Clinometer commonly used by foresters.JPG|right|thumb]]
-==Manufacturers==
+== Measuring Diameter ==
-Suunto
-Haglöf
+To calculate the diameter of a tree, wrap the tape(diameter side facing user) around the tree at 4.5 feet (137.16 cm) above ground. Where the number "0" aligns with the rest of the tape, this is the diameter of the tree.
-Brunton
+[[Image:Using a DTApe.JPG|thumb|left|200px|This shows Brandon measuring the trees DBH at 4.5 feet above ground. He is making sure that the tape is perfectly level and that the tape is not kinked, so as not to mess up the reading of the diameter]]
-Silva
+[[Image:Measuring dbh.JPG|thumb|center|300px|Thus this tree has a diameter of 16 inches (40.64 cm).]]
-==See Also==
-[[Inclinometer]]
+=== References ===
+<references/>
 [[Category:Forestry]]