This weekend I found the heights of some trees in the knoll so I did some research to better understand how exactly a hypsometer works. Modern hypsometers like the TruPulse model we use in the lab fire a laser to establish a triangle then use trigonometry to calculate the exact height of the tree from angles and lines of this triangle. Three laser shots are made; first to establish the distance to the tree, next to the base of the tree, then to the top of the tree. Using the angles at top and bottom of the tree and distance we can calculate the tangent and then height of the tree. Also in my research I looked up the price range for a hypsometer and a possible method around this. The TruPulse models we use the lab start at $750, but I found an app called smart measure from Google that can be downloaded to a smart phone for $0.99. This app might be worth testing for a cheaper method of tree height data collection that more people could have access to.
Image from: http://en.wikipedia.org/wiki/Hypsometer
Link to Trupulse hypsometer: http://www.forestry-suppliers.com/product_pages/View_Catalog_Page.a...
Link to Smart Measure: https://play.google.com/store/apps/details?id=kr.sira.measure