Thanks Ed- I understand the method now. Is it safe to assume measuring deciduous trees in a leafless state would be more accurate, in terms of a good laser shot through a crown?
Steve On Mon, Oct 6, 2008 at 11:30 PM, Edward Frank <[EMAIL PROTECTED]> wrote: > Steve, > > No there isn't any difference in the accuracy of the clinometer at any > angle. You just need to see the top of the tree. Generally being back > enough so that the angle is close to 45 or so is generally better for seeing > the true top. Steeper angles mean you are more likely to be at a point > where the true top may be hidden by outward jutting branches. The farther > you get away then the more the error in reading the clinometer accurately > affects the accuracy of the measurement. The clinometer is mechanical, so > if say it were off by 0.2 degrees high, it would read high 0.2 degrees at > all angles. By shooting both the top and the bottom angle with the > clinometer any intrinsic errors in the calibration of the clinometer will > tend to offset between the top and bottom angles - not completely but close. > > 45 degrees is just a ball park suggestion. You need to find the top of the > tree so you must shoot from wherever it gives you a good line of sight. > Sometimes it will be steeper, sometimes a shallower angle. In general the > key is to explore the top with the laser rangefinder scanning for the > highest point. At the the same angle or within a couple of degrees, the > greatest distance with the rangefinder - the higher the top. Typically what > appears to be the top at first glance is not really the highest point. Scan > around and find the highest combination of distance and angle. It may be a > obscure branch back into the apparent top mass of canopy that is the actual > highest point. Remember the branch at the greatest distance at or close to > the steepest angle is the tallest top. > > Ed > > > > Join me in the Eastern Native Tree Society at > http://www.nativetreesociety.org > and in the Primal Forests - Ancient Trees Community at: > http://primalforests.ning.com/ > > ----- Original Message ----- > *From:* Steve Galehouse <[EMAIL PROTECTED]> > *To:* [email protected] > *Sent:* Monday, October 06, 2008 10:54 PM > *Subject:* [ENTS] Re: Measurement methodology question > > Bob, ENTS- > > Thanks, I borrowed one of my kids' calculators, and now know how to plug in > the SINE function---SIN(degrees)value x laser distance--right? top and base. > Is there any difference in accuracy regarding slope? Is taking a higher > clinometer degree reading more accurate than a lower one? > > Steve > > On Sat, Oct 4, 2008 at 8:33 AM, <[EMAIL PROTECTED]> wrote: > >> Steve, >> >> Unforntunately not. The slope scale IS the tangent value x 100 and its >> use assumes a level baseline. You have to use the laser distance to the >> actual target and the degrees to that target with the formula: distance x >> sine of angle. >> >> Bob >> >> -------------- Original message -------------- >> From: Steve G <[EMAIL PROTECTED]> >> >> > >> > ENTS >> > >> > I've just acquired a clinometer with both degree and percent scales. I >> > understand the sine method of measuring with clinometer and laser >> > rangefinder(at least I think I understand). Can I simplify an accurate >> > measurement by taking rangefinder distance times % slope of >> > clinometer, without translating a degree reading to a sine value? >> > Intuitively it seems it should get to get to the same figure from >> > different directions.--is this correct? >> > >> > Steve >> > >> >> > > > --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org You are subscribed to the Google Groups "ENTSTrees" group. To post to this group, send email to [email protected] To unsubscribe send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/entstrees?hl=en -~----------~----~----~----~------~----~------~--~---
