White Pine (Pinus strobus) at Gillies Grove, Arnprior

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wrecsvp
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White Pine (Pinus strobus) at Gillies Grove, Arnprior

Post by wrecsvp » Sat May 30, 2015 10:09 pm

Made a trip to Arnprior (Gillies Grove) on May 24th with naturalist Arthur Goldsmith and members of my family to measure the well-known tall White Pines (Pinus strobus) there, and especially "the" tall White Pine lately in the news (link below). Nothing obviously remarkable about the site (level ground, etc.), apart from the fact that the White Pines were never logged from it. I am happy to say we confirmed a number of trees taller than what I had previously measured at the site (125'), with a small handful found to be 130+' tall. I measured the "tallest" tree several times, and found it to be consistently between 135-140' tall, with one measurement reporting 141' (43m) which as optimists we can take as "the" measurement from my device. One of the best stands of White Pine in Ontario, with many trees in the 110-130' tall range. Well worth the visit.

http://www.natureconservancy.ca/en/wher ... raper.html
Attachments
see the kid at the base?
see the kid at the base?
wp2.jpg
wp3.jpg
Top of tree from measurement location
Top of tree from measurement location
wp5.jpg
Bench at base of tree
Bench at base of tree

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Will Blozan
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Re: White Pine (Pinus strobus) at Gillies Grove, Arnprior

Post by Will Blozan » Sun May 31, 2015 8:32 am

Wow looks like an awesome grove! We certainly need more numbers from Canada.

Forgive my unfamiliarity with the Nikon 550 but the photo of the 141' height appears to be a tangent measurement? This would be the reason for the range of heights. Using the sine-based function is what will give the actual height. Were you taking distance readings to the top and base or just angles?

Thanks for the post!

Will

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dbhguru
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Re: White Pine (Pinus strobus) at Gillies Grove, Arnprior

Post by dbhguru » Sun May 31, 2015 11:57 am

Will,

No, the Nikon Forestry 550 does provide a sine-based height. Their follow-on unit, the Nikon Forestry Pro, gives both sine and tangent heights implemented as two and three point routines. The tangent routine is the three point one, but the 550 offers only the two point sine-based routine. The little triangle drawn on the side of both the 550 and the Forestry Pro is misleading for the two-point routine. It shows the distances to top, base, and the total angle between the lines. It connects the top and base points with a vertical line, and gives the length of the vertical line as the vertical separation between top and base. However, as you know, such a drawing isn't geometrically valid since there are actually two separate right triangles involved with different baselines used to solve the problem, so that the vertical distance between top and base needs to be separated into two offset vertical lines, one for the top and the other for the base. I suppose they thought the diagrammatic simplification was necessary or just easier to implement.

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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Will Blozan
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Re: White Pine (Pinus strobus) at Gillies Grove, Arnprior

Post by Will Blozan » Sun May 31, 2015 12:45 pm

Thanks Bob! Sure is nice to see some solid white pine numbers from Canada.

Will

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wrecsvp
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Re: White Pine (Pinus strobus) at Gillies Grove, Arnprior

Post by wrecsvp » Sun May 31, 2015 7:30 pm

Hi guys,
indeed this measurement was via the ENTS-approved sine approach at base of tree and tip of highest branch (exactly what Bob said). Range in heights likely partially due to wind, which was fairly strong. I verified the device on some known distances/heights the same day. Part of the motivation for the trip was to check on the height reported in the media (quoted at 154'), which seemed high to me. I don't know by which methods etc. the tree was measured by others, but it does have a noticeable lean...
Owen

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Larry Tucei
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Re: White Pine (Pinus strobus) at Gillies Grove, Arnprior

Post by Larry Tucei » Mon Jun 01, 2015 1:05 pm

Wow- That is some really tall White Pine for that far north. I'd almost bet somewhere up there is a 150' tree waiting to be measured. Larry

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dbhguru
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Re: White Pine (Pinus strobus) at Gillies Grove, Arnprior

Post by dbhguru » Tue Jun 02, 2015 10:48 am

Larry, Owen, Will, et. al.,

Arnprior, Ontario lies at about 45.5 degrees north latitude. Some of the big pines in the Porcupine Mtns, MI are at around 46.5 degrees. So long as there is a climatic influence from the Great Lakes, the trees can surprise us with their sizes. But, once away from the lake influence, heights drop.

I have measured white pines in Algonquin Provincial Park to around 130 feet. One tree was perhaps 136 feet. I had a hard time locating its base. The latitude was just under 46 degrees. I expect that some white pines in southern Ontario may make it to 150 feet. Finding them and setting the northern limit to different height thresholds is a very worthy project.

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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