North Chagrin Reservation: Cumulative Forest Data

[ElijahW]

Stefan,

I understand. Don't sell yourself short, though. You've done an excellent job keeping the northern Ohio measurements up to date.

Elijah

[sradivoy]

Thanks Elijah! My experience has been that its usually better to err on the short side than to exaggerate on the tall side. There are times when I do take the highest hit. Recently I measured the state's tallest tree at 172 and went with it because I had a much better view of the top than the 167 hit that was shot at a very high angle from below. I think when you lose track of the tallest leader due to changes in perspective while encircling the tree it makes sense to take the highest hit. But if you measure the same top from different positions it would make more sense to me to take the average value, all things being equal. Why would you favor one value over the others? They should all be treated equally in an unbiased way. But if you get a repeatable max height than by all means go with it, because even if you took the average you would get the same result anyway.

[Steve Galehouse]

Stefan-

Was the 172' tree the Sand Run tulip?

Steve

[bbeduhn]

Stefan,
The highest number, equipment permitting and being read correctly, will be the most accurate. Adjusting footing to get the clickover point yields better accuracy than just pointing and shooting. Some terrain simply does not lend itself well to microadjustments. Your best and most accurate shot will be the higher figure. It's not a matter of bias. If you keep shooting from different angles, you're likely to top your first effort, even if it's just by a few inches. I routinely undermeasure when I'm trying to measure a large area of trees. When I recognize a tree as being extraordinary, I take extra time and extra angles and can often coax an extra foot or at least half a foot out of a tree. The extra height is there all along, it just takes extra effort to find it.
Brian

[sradivoy]

Steve,
I was referring to the one that was named after you in the hocking hills region.

Brian,
My rangefinder can only measure within half yard increments. No click stop technique was used for either vector. I can only read my handheld clinometer within a half a degree due to sway. Considering these two variables it is possible to get a max hit that is taller than the actual height of the tree (something like a lidar hit can also be a false hit). I don't have a good reason to assume that my max reading is in fact the actual true height. The two constants are the same leader (the top of the tree) and the base of the tree (which I tape wrapped at precisely 4.5ft midslope) for all five measurements taken from different locations.
Stefan