Rangefinder Recommendations

General discussions of measurement techniques and the results of testing of techniques and equipment.

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JHarkness
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Re: Rangefinder Recommendations

Post by JHarkness » Sun Jul 22, 2018 11:05 am

Bob,

It will be interesting to see what the pine's end of season measurements yield. Do you have any idea how old the tree is, I assume it's older than the Elders Grove or Trees of Peace at Mohawk, but I'd be interested to hear what you suspect.

When I visit Ice Glen, are there any trees you'd like me to check up on? Some of the white ashes (which were all still healthy when I last saw them), shagbark hickory, or maybe some of the maples?

Joshua
"Be not simply good; be good for something." Henry David Thoreau

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Erik Danielsen
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Re: Rangefinder Recommendations

Post by Erik Danielsen » Sun Jul 22, 2018 11:25 am

Josh,

Glad you will now be fully equipped! I find the "farthest" setting quite capable for brush penetration when paired with a tripod, note that the specialized "filter" mode is a bit more of a surveying tool meant for reflective targets and use with a special optical filter- not much use for trer measuring.

I forgot to note one of my favorite advantages to the 200 series is that they use AA batteries, which are never hard to find. A pair of energizer lithiums last a long time and weigh a fraction of what alkalines weigh, as well.

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JHarkness
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Re: Rangefinder Recommendations

Post by JHarkness » Sun Jul 22, 2018 11:36 am

Thanks Erik,

Yes, I was just reading through the units manual and saw that about the filter mode. I was quite pleased to hear that it can take AA as well as lithium batteries, most of the other rangefinders I looked at took a special size of lithium battery, and some of the batteries were awfully expensive as well.
"Be not simply good; be good for something." Henry David Thoreau

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dbhguru
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Re: Rangefinder Recommendations

Post by dbhguru » Sun Jul 22, 2018 6:43 pm

Joshua,

Ice Glen pine should be over 300. We dated two others, both down now to 300 and approximately 325. I exoect that the Ice Glen pine is closer to 325, and maybe a little more.

It would be good to update the Rucker Index for TIce Glen. It was once 128. Between losses and gains, it may be about the same. Presently, there’s only ine sute in Ll Massachusetts and that, of course, is MTSF. The tallest hemlock is the one by the trail innthe center of the Glen. It was about 136.5 the last time I measured it. As I recall, it’s a little over 10 feet around.

Bob
Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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JHarkness
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Re: Rangefinder Recommendations

Post by JHarkness » Sun Jul 22, 2018 10:12 pm

Bob,

I don't know how I missed the Ice Glen Pine when I was there, I suppose I was just very focused on the hemlocks and the aesthetic qualities of the glen I wasn't really looking for other tall trees. It would be interesting to establish a database of white pine height growth in regards to age, say for example that an 80 year old pine grows 14 inches on average per year and a 200 year old pine grows 6 inches per year, it may be a good way to get an estimate of a trees age, assuming that the tree is not stressed.

I would be happy to work on a Rucker Height Index next time I'm there, I assume ten species would be adequate? I've looked through your posts on the site in the past and I saw most of the trees that were in the Rucker Index, most seemed to be in good health with little sign of crown breakage, so perhaps the Rucker Index has risen a bit, I wouldn't expect much though.


There are actually two huge hemlocks at the center of the Glen, just a few feet apart, I believe the one is the tall one you speak of, I saw nothing taller when I was there, but it's neighbor could easily be at least 130', and there are a few others nearby that look to be in a similar height range. The tall hemlock unfortunately was in very poor condition last time I saw it, do you know if there are any plans for hemlock treatment? I suspect it doesn't have more than another year or two. The tree has no HWA, just EHS so imidaclorpid won't be of any use.
IMG_0765.jpg
These were the tallest hemlocks I found, the one on the right is the taller of the two, is this the height champion? They are right in the center of the glen by a small spring.

There's actually a slightly larger hemlock, but probably only around 100' in height, perched on top of a boulder a little ways off trail in the center of the Glen, I would guess that it's at least 12', maybe more. We'll find out soon.

Joshua
"Be not simply good; be good for something." Henry David Thoreau

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JHarkness
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Re: Rangefinder Recommendations

Post by JHarkness » Sun Jul 22, 2018 10:15 pm

Bob,

Also, are there any other sites in the Taconics and western Berkshires you'd like me to check out? I'm only half an hour from Bash Bish Falls and Race Brook, the latter is known to have old growth hemlock, white cedar and I believe some red spruce at the higher elevations.

Joshua
"Be not simply good; be good for something." Henry David Thoreau

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addy
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Re: Rangefinder Recommendations

Post by addy » Mon Jul 23, 2018 3:31 pm

I have a recent model (purchased Spring 2017) Nikon Forestry Pro, purchased pretty much because its the only laser hypsometer I can afford. ($330 for a new one on ebay) I've shot the heights of about 50 trees with it. The linear distance it operates at is anywhere between 10-500 meters. I haven't used it anywhere near the maximum of its range, usually near the minimum end. I haven't noticed any problems with being able to hit a target. Since I'm in Florida the terrain is usually extremely flat so I have hardly used the 3-point mode, I can just shoot the height straight off since I'm usually level with he target or nearly so. The accuracy is to plus/minus 3 feet I found in a spec somewhere, and its light, quick & easy to use. I use it for messing around and measuring heights of trees to submit to the State Champion trees program. Since the DOF will come out and shoot their own measurements anyway, hopefully with more pricey gear I can't afford, I don't care so much about being super accurate. Its perfect for my needs, but that's because I'm not nearly as much into dendromorphometry as a lot of folks here, I just want a reasonably close height without having to spend an hour slogging around in swampy terrain. It really depends on what you intend to do with it I guess, since I just use it for heights that will be re-shot anyway (or just filed in my data & forgotten) plus/minus 3 feet is acceptable for me.

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JHarkness
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Re: Rangefinder Recommendations

Post by JHarkness » Mon Jul 23, 2018 7:15 pm

Addy,

That's my thought on the matter as well, but I feel that I need something more accurate as I likely have several height champions on my property and don't really want to invite hoards of people in to come take accurate measurements. I also plan to take the rangefinder on remote hikes in the Adirondacks, nothing is easy to get to there and it may be impossible to find a tree again without extensive knowledge of the area so the first measurements need to be accurate. I can guarantee you that the people in charge of New York's big tree register aren't going to hike twenty miles into the Adirondacks. It really depends on what one needs out of a unit, I was happy to spend a little bit extra and get a more accurate reliable unit.

Joshua
"Be not simply good; be good for something." Henry David Thoreau

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dbhguru
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Re: Rangefinder Recommendations

Post by dbhguru » Tue Jul 24, 2018 11:05 am

Addy, Joshua, et al.,

Addy, the Nikon ForestryPro is accurate on close targets to about +/- 1.5 feet. If the target is solid and brightly lit, you can often get to within +/- 1.0 feet. But, you have to do a lot of testing to determine for yourself and your particular instrument the trustworthiness of your measurements. And don't rely on averaging multiple shots from different directions unless you are certain that you are hitting the same target. Practice makes perfect.

For more distant, less distinct target, within +/- 3.0 feet is more common. Here, I'm speaking about the accuracy of the infrared laser, not the combination of the laser and tilt sensor. The tilt sensor is probably accurate to +/- 0.5 degrees or a little better, maybe a quarter of a degree. You probably don't want to worry about analyzing the combination of errors. Sometimes they compound, and sometimes they offset one another, at least partially. When they compound on a distant target, you can be off by maybe +/- 4 feet, but you keep shooting and you can often get a sense of what leads to the highest measurement. For example, sometimes shooting a narrow tip against a bright sky can lead to a significant overage.

A very important point to understand is that the 3-point height method is just the automated version of tape and clinometer, and carries all the risks of that traditional method. If you can see both base and top from the same location, use the 2-point height method. If you can see just the top, use the hgt (steady, not blinking) mode to get height above eye level, and figure some other way to get height from eye level to base, for example the 3-point method, shooting to the trunk, and then taking angles to the base and at eye level. You then add the two results together for total height.

In terms of other people coming in with more advanced equipment and getting more accurate results - don't bet on it. This BBS has an encyclopedia's worth of posts on mis-measured trees coming from ostensibly reliable sources, often state people. It is one of the early reasons NTS was established in the first place. The problem is that people learn short-cut measurement methods without understanding the assumptions behind them, however, with the Nikon Pro, the 2-point method and just the simple non-blinking hgt mode do not make the simplifying assumptions that the 3-point method makes.

Bob
Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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dbhguru
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Joined: Mon Mar 08, 2010 9:34 pm

Re: Rangefinder Recommendations

Post by dbhguru » Tue Jul 24, 2018 11:05 am

Addy, Joshua, et al.,

Addy, the Nikon ForestryPro is accurate on close targets to about +/- 1.5 feet. If the target is solid and brightly lit, you can often get to within +/- 1.0 feet. But, you have to do a lot of testing to determine for yourself and your particular instrument the trustworthiness of your measurements. And don't rely on averaging multiple shots from different directions unless you are certain that you are hitting the same target. Practice makes perfect.

For more distant, less distinct target, within +/- 3.0 feet is more common. Here, I'm speaking about the accuracy of the infrared laser, not the combination of the laser and tilt sensor. The tilt sensor is probably accurate to +/- 0.5 degrees or a little better, maybe a quarter of a degree. You probably don't want to worry about analyzing the combination of errors. Sometimes they compound, and sometimes they offset one another, at least partially. When they compound on a distant target, you can be off by maybe +/- 4 feet, but you keep shooting and you can often get a sense of what leads to the highest measurement. For example, sometimes shooting a narrow tip against a bright sky can lead to a significant overage.

A very important point to understand is that the 3-point height method is just the automated version of tape and clinometer, and carries all the risks of that traditional method. If you can see both base and top from the same location, use the 2-point height method. If you can see just the top, use the hgt (steady, not blinking) mode to get height above eye level, and figure some other way to get height from eye level to base, for example the 3-point method, shooting to the trunk, and then taking angles to the base and at eye level. You then add the two results together for total height.

In terms of other people coming in with more advanced equipment and getting more accurate results - don't bet on it. This BBS has an encyclopedia's worth of posts on mis-measured trees coming from ostensibly reliable sources, often state people. It is one of the early reasons NTS was established in the first place. The problem is that people learn short-cut measurement methods without understanding the assumptions behind them, however, with the Nikon Pro, the 2-point method and just the simple non-blinking hgt mode do not make the simplifying assumptions that the 3-point method makes.

Bob
Robert T. Leverett
Co-founder, Native Native Tree Society
Co-founder and President
Friends of Mohawk Trail State Forest
Co-founder, National Cadre

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