Difference between revisions of "AY Honors/Forestry/Answer Key"
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==2. Learn the proper use of the following common forestry tools and practice using them on trees in a forest. Record the information for each tree giving also the common name of each tree:== | ==2. Learn the proper use of the following common forestry tools and practice using them on trees in a forest. Record the information for each tree giving also the common name of each tree:== | ||
===a. DBH (diameter at breast height) tape – measure the diameter of trees (or measure the tree circumference and calculate the diameter)=== | ===a. DBH (diameter at breast height) tape – measure the diameter of trees (or measure the tree circumference and calculate the diameter)=== | ||
| + | ====Description of a DBH Tape==== | ||
A DBH-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 {{units|140cm|4.5 feet}} above the ground, where it is most convenient to measure diameter. DBH is measured up high so to avoid measuring a tree's butt swell. Butt swell is where the base of the tree is unconventionally fatter than 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. | A DBH-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 {{units|140cm|4.5 feet}} above the ground, where it is most convenient to measure diameter. DBH is measured up high so to avoid measuring a tree's butt swell. Butt swell is where the base of the tree is unconventionally fatter than 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. | ||
Revision as of 00:23, 20 November 2011
1. Prerequisite: Tree Honor
2. Learn the proper use of the following common forestry tools and practice using them on trees in a forest. Record the information for each tree giving also the common name of each tree:
a. DBH (diameter at breast height) tape – measure the diameter of trees (or measure the tree circumference and calculate the diameter)
Description of a DBH Tape
A DBH-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 140cm
above the ground, where it is most convenient to measure diameter. DBH is measured up high so to avoid measuring a tree's butt swell. Butt swell is where the base of the tree is unconventionally fatter than 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.
Diameter is easily measured because the tape is calibrated in units of 3.14 ([math]\displaystyle{ \pi }[/math]) inches or centimeters. The tape is actually measuring the tree's circumference but since circumference and diameter are related by pi, the diameter can easily be obtained. The only problem with the diameter tape is that the measurements assume the tree's trunk cross-sections are perfectly circular. Thus the diameter tape just gives an approximation, regardless it is the most commonly used dendrometer for DBH.
