Nikon Forestry Pro can't see branch ends in winter

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Jim Scheff
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Joined: Fri Jul 22, 2011 4:54 pm

Nikon Forestry Pro can't see branch ends in winter

Post by Jim Scheff » Sat Mar 09, 2019 11:06 am

Hey folks,
I've been digging through the forums and haven't found a discussion on this - sorry if it's been covered already. I've got a Nikon Forestry Pro, and waited until leaf-off for some measurements to get around clutter issues. However, the thing just doesn't "see" branches under about 2". Has anyone else run in to this? Do I have a useless $350 tool? The cheapest used TruPulse 200 I can find is still $500.

I come across a lot of remarkable trees in my work and backcountry rambles, and never get more than dbh. Right now I've got a contender Kentucky state champion bitternut hickory, and I'd really like to get some good measurements.

Thanks for any advice.
big bitternut and Jim.jpg
big bitternut and Tina.jpg

ryandallas
Posts: 116
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Re: Nikon Forestry Pro can't see branch ends in winter

Post by ryandallas » Sat Mar 09, 2019 12:31 pm

Jim,

I have not had this problem. That's strange. Then again, I have used my forestry pro almost exclusively on tulip trees, which have the nice big dried flowers on the ends of the twigs.

Mount a thin branch onto something and try shooting at it.

That is an amazing hickory, by the way!

ryandallas
Posts: 116
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Re: Nikon Forestry Pro can't see branch ends in winter

Post by ryandallas » Sat Mar 09, 2019 12:49 pm

Jim,

I just stuck a 3/16" diameter twig into the snow and shot at it. Put it well ahead of a well-defined backdrop. Forestry Pro was able to distinguish between the backdrop and the twig--40 feet versus 72. You may have a defective product.

The Forestry Pro has a "1st" setting and a "DST" setting. Have you tried fooling around with these? It's unlikely that they would be a problem if you're shooting against the sky, but you might as well take a look at them.

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Erik Danielsen
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Re: Nikon Forestry Pro can't see branch ends in winter

Post by Erik Danielsen » Sun Mar 10, 2019 1:23 pm

I have had the same experience with certain units and usually have felt it to be specific to tree species (though I have not used any of the nikons). Bitternut Hickory's fine twigs and for some reason white ash have given some a really hard time. Did you try seeing if you had any better luck moving around so that you'd be more or less perpendicular to the direction of daylight? I'm not sure that that would help, but given mentions in manuals for these rangefinders the intensity and direction of reflected daylight on the target may influence whether the laser return is strong enough to detect vs ambient.

I'm with Ryan, the columnarity of that bitternut is nuts!

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mdvaden
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Re: Nikon Forestry Pro can't see branch ends in winter

Post by mdvaden » Sun Mar 10, 2019 6:09 pm

This reminds me why I remeasured Humboldt Honey, the world's tallest maple, when it still had some leaves on the tips. I was using an Impulse 200LR and it seemed hit and miss aiming for tiny twig ends. But when there was some leaf, it would catch it most of the time.
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Jim Scheff
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Re: Nikon Forestry Pro can't see branch ends in winter

Post by Jim Scheff » Tue Mar 12, 2019 12:17 pm

Thanks for all of the responses. I've tested it a lot in my yard and woods behind my house, on pin and shingle oaks, black cherry, and a couple other species. Sometimes I can't even get a hit off of branches 4" or 5" diameter that are clearly in the viewfinder. I'll get get a read on something larger and scan up, and just lose it even on branches as big as my arm. I did get some consistent reads from a shortleaf pine canopy in the woods recently - I suppose the needles provided enough to work off of. I wrote to Forestry Suppliers, since I bought it from them via Amazon. It's been 3 years since the purchase. Even though it's been three years since I bought it I'm not optimistic that there's much to bee done. I wish I'd taken care of it earlier, but I kept thinking the problems were all user error, but I don't think that's the case now.

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dbhguru
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Re: Nikon Forestry Pro can't see branch ends in winter

Post by dbhguru » Tue Mar 12, 2019 2:54 pm

Jim,

Sounds like you have a defective unit. How much error are you willing to live with, e.g. 3 feet? If you can live with an approximation, you can use the tree-height routine (blinking horizontal). There are ways of making this method work better than the conventional method. I'm pleased to outline a few routines if that would help.

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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addy
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Re: Nikon Forestry Pro can't see branch ends in winter

Post by addy » Fri Mar 15, 2019 4:57 pm

With mine I've never come across any apparent problem bouncing around the canopy in sine mode off of what appear to be very small branches.

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