Jimmy, The stick method isn't very accurate, but inherently it is not any worse than the clinometer at a set difference from the base method used in most forestry applications. It works by similar triangles. The problems areas are several with the method.
1) First the stick must be exactly vertical or the height of the tree will be exaggerated. 2) The size of the triangle formed by your eyes, the top of the stick and the base of the stick is small compared to the size of the tree. Therefore any errors in ay of those measurements, or in the stick not being vertical will be exaggerated by the difference in scale between this small triangle and the large one formed by the tree and your eyes. 3) There still is the problem caused by the top of the tree not being directly above the base of the tree. If, as is usually the case, the top offset point is generally toward you, this will exaggerate the height of the tree. 4) There is still the problem that determining which branch is the actual highest point of the tree is difficult and easy to misidentify. Often what appears to be the tallest top, is actually the tip of a lower branch leaning toward the viewer. Still there are some advantages to the stick method over the set distance to the base and clinometer method. The clinometer and distance from the base method requires that the person doing the measurement and the base of the tree all be on the same level. That doesn't matter with the stick method. The other big advantage as I see it, is that people using the stick method realize that the heights they are determining are approximate, while those using the distance from the base and clinometer method have deluded themselves that because they are measuring something with instruments, that this somehow makes the readings accurate. Instrument readings don not generate valid heights if the methodology is flawed. The latter has been the biggest problem in trying to bring better height measurements to discussion, as people using the flawed methodology refuse to see the errors generated in the process. Ed Frank http://nature-web-network.blogspot.com/ http://primalforests.ning.com/ http://www.facebook.com/profile.php?ref=profile&id=709156957 ----- Original Message ----- From: Jimmy To: ENTSTrees Sent: Friday, January 15, 2010 3:55 PM Subject: [ENTS] Height Measurement I'm new to the game and still using the old Hold out a stick height measurement technique. How accurate is that? Here's a sugar maple I measured Using that Technique. http://www.flickr.com/photos/38649...@n08/4272915937/in/set-72157623216597308/ This is the largest forest grown sugar maple I've seen in Minnesota, 10'9" cbh 83' tall Crown 61'. How does that compare to other Sugars? ------------------------------------------------------------------------------ -- Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected] Email Options: http://groups.google.com/group/entstrees/subscribe?hl=en
-- Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected] Email Options: http://groups.google.com/group/entstrees/subscribe?hl=en
