Bob: In this case I just averaged all four measurements. I felt the variance in the heights we obtained were within the variance of the rangefinders. I mostly measure trees alone and usually take two height measurements from two locations and when I get a variance greater then +/- 1.5 feet I do several things. 1. I check my arithmetic. 2. I repeat my measurements previously made. (I use a little red flag that disc golfers use to mark my location). 3. If the variance is still to great I take more measurements from different locations until I get a cluster and average the cluster and ignoring outliers- My record for one tree, same top is 10 shots and a cottonwood with 6 tops with 12 shots. This tree defeated me because I was getting the tops mixed up from different vantage points. This past year I started using the 4 1/2 foot mark to get my bottom sine distance and then just adding that 4 1/2 feet into the total height. Another hint: Try not to have a preconceived notion of what your results should be. Concentrate on taking good readings(especially clinometer) and recording your results immediately and in legible form. I can not believe the time I have wasted because of taking bad notes - which I always blame on someone talking when I am measuring. Some other things to consider: Are you using a clickover point for top sine distance? Have you checked your calibration on rangefinder and clinometer? I am not familiar with the Bushnell's variance allowance. Hope this helps Turner Sharp On Dec 14, 8:14 am, BobinKy <[email protected]> wrote: > Thank you for the nice report on the great Sycamore in West Virginia. > In your report you said you took four measurements from three > locations, How did you settle on 117.4 height as the best of the four > measurements? Here in Kentucky I also use a laser rangefinder > (Bushnell Legend 1200) and scientific calculator to measure various > trees. Selecting the best height measurement when I take multiple > measurements is sometimes a question when I do my measurements. Do you > have any suggestions? > > Bob > Kentucky > > On Dec 13, 10:31 pm, turner <[email protected]> wrote: > > > ENTS: I had a chance to revisit and remeasure this great Sycamore this > > past > > Friday, December 11, 2009. No foliage to peer through but a stiff cold > > wind was blowing. > > Bob Hannah, a WV DOF Forester, and I spent a cold two hours measuring > > this tree; Here are the results" > > CBH is 311.4 inches or 25.95 feet > > Height is 117.4feet > > Crown Spread is 128 feet which gives a BTP total of 460. > > > Some other measurements made: > > CBH on high side is 306 inches or 25.5 feet > > CBH on low side is 337.8 inches or 28.15' > > There was a 32 inch height difference between the high and low side. > > The 311.4 " CBH was taken 16 inches above/below the high/low side Both > > the high and low side CBH were affected by anomalies which is one > > reason we did not go with an average of the two. All measurements were > > taken underneath the moss buildup. The high and low side were found > > with a level. I could not find the push pin I left in the tree during > > my first visit, but it appeared to me we were about 3 inches below my > > previous CBH measurement. > > Two crown heights were measured. The tallest of the two were measured > > 4 times by two different lasers(Nikon 440 and 550) from 3 locations. > > Heights ranged from 116.5 to 118.7 with us settling on 117.4 as best. > > The trunk went up 49 feet where it had 6-7 main limbs going off in all > > directions. From a eyeball guess the diameter at that point was in the > > three- four foot range. The tree has a pronounced lean over the > > adjoining road. Because of the swollen butt, Bob and I speculated that > > at on time there may have been another stem that died and has been > > totally enveloped by the remaining stem at the base. Tree has no sign > > of decay at base. > > Turner Sharp
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