Page de discussion de Martin
- (en - 2015/03/01) Tamaris commun 'Tamariska v Piestanoch' à Pod Parovcami street, Piestany, Slovaquie
- (en - 2014/07/05) Charme commun 'Hrab v Humennom' près du manoir park, Humenne, Slovaquie
- (nl - 2014/06/01) Ginkgo 'Ginko v parku medzi kastielmi I-1' dans le park, Nova Ves nad Zitavou, Slovaquie
- (en - 2013/08/06) Pin de l'Himalaya 'Borovica himalajska v Arborete Mlynany I-1' à la lisière du Arboretum Mlynany, Vieska nad Zitavou, Slovaquie
- (en - 2013/08/06) Pin flexible 'Borovica ohybna v Arborete Mlynany I-1' à la lisière du Arboretum Mlynany, Vieska nad Zitavou, Slovaquie
- (en - 2013/01/13) White poplar in the park, Strazske
- (de - 2013/01/12) Chêne pédonculé 'Dub v Machulinciach' à Machulince, Machulince, Slovaquie
- (en - 2012/12/02) Aulne vert 'Jelsicka v Moravskom Lieskovom' dans le jardin de Moravske Lieskove, Moravske Lieskove, Slovaquie
- (en - 2012/07/24) Saule pleureur 'Smutocna vrba pri jazierku' à la lisière du school, Piestany, Slovaquie
- (en - 2012/03/19) London plane near the border of the Sokolovce in Sokolovce
You write: probably tallest white poplar of Slovakija, but you probably mean "biggest" white poplar. "Tallest" means the same as "highest". You have another Populua alba at this website of 41.9 m, wich is higher / taller.
"Alnus viridis" - About 58,700 google search results
"Duschekia alnobetula" - About 1,560 google search results
A very great height for Platanus but surely possible. The record of Europe wich is sure is 48,56 m for a plane in Bryanston, Dorset, England, measured by climbing with direct tape drop. Before it was already measured as 48,5 m with laser by Robert van Pelt, a famous tree measurer from Washington State, USA.
You write you measured the 45 m tree exactly. We like to know your measurement method.
In fact we don't trust measurements with clinometer with a baseline to the trunk of the tree or Vertex hypsometer (both the 'tangent'- method: you measure the distance to the trunk as well as the angle to the top and calculate from these the height) not to much, we have experienced a lot of mismeasurements were made with this method, also by us before we started to measure with laser, with the 'sine'- method: you measure the straight distance to the top as well as the angle to the same top and calculate from these the height); this is more exact in the case that the top is not vertical above the trunk.
Tim for this reason has made the system "measured exactly by laser or by climbing with direct tape drop" wich you should use only in that case. Our own measurements before 2009 with Suunto clinometer or Vertex hypsometer we call 'around'.
Kind regards, Jeroen
I understand your doubts about the height, but it based on official data published not only on the internet but also in many books about the protected trees in Slovakia. The village Sokolovce is very near my home in Piestany. It is very nice tree, the oldest and tallest london plane tree in Slovakia. You are welcome to measure the height of this tree :-) Best regards, Martin
Some of the for-shortening in these photos is really apparent, this London Plane does not look c40 metres tall when you see the lady at the base for perspective. The more and more I see this, you really do have to be at some considerable distance from the tree to attempt a measurement using photos like this.
This was my first attempt at measuring a tree from photos and person of known height but I now know that I was far too close to the tree when photographing here. The for-shortening is very apparent, I measured it at 105 feet, 32 metres, it was measured in 1984 at 38 metres, 124 feet. My longer distance photos, 1 km, I have measured it from photos at somewhere c139- feet, c42.5 metres. The degree of error from my first measurement attempt when taking the photo fat too close to the tree is glaring.
Indeed the photo of the plane tree in France with the lady has much to much foreshortening to be used for a hight estimate. I am still serious that you better should stop with that method, results are only to be trusted if you are quite far from the tree and have the whole tree as well as the person or other object at the base good in vieuw end exactly measured. But even then, if the tree is leaning towards you or away from you it will give faults. So save some money for a laser (cheaper than a good camera) and you will see this works much better!
I have an example here:
This photo I took a year ago, from a distance of about 50 m. My wife, Gerdien, is 167 cm, with shoes 1.7 m. The tree at the photo is 14,5 times the height of Gerdien, wich gives a height of 24.65 m. In fact it is 30.2 m!
In my opinion, trees with unknown height measuring method should always be marked as "around", not "exactly", even if the measurements were from "official" sources, like www-sites or books. That a height has been published does not mean it has been reliably measured. Publishers, list-makers and even measurers are usually not aware of the error possibilities of tangent methods. I was also not before I started to measure with a laser rangefinder. For example, three large lindens in Germany. The published heights were 44 m, 42 m and 42 m. My laser measurements 30 m, 28 m and 32 m, respectively. Published heights are still today mostly measured with tangent methods.
you are right, the accurate measurement of height is quite often the problem if height is not measured exactly by tape or laser scanner. I presume that the heights of protected trees in Slovakia was measured by one of above mentioned methods. To make sure, I would like to ask the official authorities which method was used in the measurement. Please be patient because a communication with the authorities may be a little bit longer even though I work at the Ministry :-) Note: most of the heights of protected trees in Slovakia were measured around the year 2003, so it will be necessary to repeat measurements. For this reason, the trees are much higher at this time of course. Have a nice day, Martin
That's great! Please, ask the equipment (brand name & model) they used.
For the website it should be good if you first had to fill in the measurementmethod. Only lasermeasurements (in fact laser with Sine method, that is direct measuring the distance to the top as well as the angle to the same top and from these two calculating with a simple formula the height and horizontal distance; you have to do this also for the heightdifference from your eye to the base of the tree) and climbing with tapedrop can be seen as exact measurements.
Measuring with clinometer or hypsometer using the Tangent method (and even measuring with a laser using the tangent method we should not accept as "exact" but as "about" or 'around", just like the "stick method"). With the Tangent method you measure the baseline to the trunk of the tree and the angle to the top. It is only exact when the top indeed is direct (perpendicular) above the side of the trunk. When the visualised top is nearer to the measurer, you will get an overmeasurement. Especially in broad crowned broadleaftrees and Cedars this is often the case.
I plead for the methods to fill in:
A. Climbing with direct tape drop
B. Laser with Sine method (for example Nikon Forestry 550 laser ranger)
C. Clinometer or tangent style hypsometer
D. Stick method
E. Photo method
Only heights measured with method A. and B. should be called "exact", the others "around".
no, you didn't understand the theory of lasermeasuring. You need to use Trigonometry.
I will explain it all the way, although with a Nikon Forestry 550 laser ranger all measurements are done automatically, so very simple.
A. You have to measure the distance to the top (we call it Distance1 = D1).
This you can measure with a simple laser ranger.
B. From exactly the same position you have to measure the angle from your eye to the same top in relation to the horizontal plane! This we call Angle 1 = A1.
The angle you can measure with a clinometer like a Suunto clinometer, wich uses a gravity - balance to determine the horizontal plane.
C. From these two data you have to calculate an imagiary rectangle with the vertical (Height 1 = H1) as well as the horizontal distance from the top. For this calculation you need the formula H1 = [Sine (A1)* D1].
Now you have the height of the top above your eye (H1).
You still have to know the difference in height between your eye and the base of the tree (H2). This you do in the same way:
D. Measure the distance to the base = Distance2 = D2(indeed take the midslope point of the base if possible).
E. Measure the angle from your eye to the base of the tree = Angle2 = A2.
F. Calculate in the same way as in C) the heightdifference between your eye and the base of the tree: H2 = [Sine (A2)* D2].
The total height of the tree is H1 + H2.
There is no difference of the total heights depending of the distance you have to the tree, only when your distance is greater the height becomes less exact, because the measuring of the angle becomes less exact when you are very far away.
The fun of the Nikon Forestry 550 laser ranger is that it is a combination of a laser ranger, with an internal digital clinometer and an automatic calculator.
(Till 3 years ago you had to buy these all separately: a laser ranger, a clinometer and a calculator).
You only have to hit at a top. At the screen you see immediately the distance to the top, the angle, the height as well as the horizontal distance of the top.
Next you hit at the base, get also this height and add these two heights. The Nikon Forestry has a modus were you can add these two measurements automatically, but I do this always by head. Also, especially with multitop trees (broadleafs, cedars, etc.) you have to scan the several tops to find what is the tallest.
I have promised Tim to make a measurement instruction. There are already very good instructions at several websites, but they are a bit complicated. The ones without the Sine - laser method are not modern and good enough.
Well, now I see Kouta has given a reaction at the same time! He knows the theory as well as the practice very well and gives a good and more simple explanation.
The only thing which was not correct in your explanation was this:
"The laser has recorded the angle between the line when the laser was pointing at the tip and that when the laser was pointing at the base."
The laser records two angles:
1. Between the line when the laser was pointing at the tip and the horizontal line.
2. Between the line when the laser was pointing at the base and the horizontal line.
With the first angle (and distance), the laser calculates the height of the part above your eyes, and with the second angle (and distance) the part below your eyes. Then these two parts are summed.
Theoretically, the reading should be the same regardless of measuring distance, but in practice accuracy decreases when you go too far.
Anyway, measuring with Nikon 550A S or Forestry is easy and fun. With a Nikon, you could do important research with the tall trees in your country. Buy it, I assure you it is worth the price!
Perhaps there are taller Douglas firs now.
This is a very good guide and I have got the giste of it. Just a couple of queries.
The laser works then by using a horizontal as a guide, how do you know you actually have a horizontal? Is there a marker, cross hair type, in the laser viewfinder to tell you?
If the tree is standing on a slope and the only windows in are from downslope views but from say 10 feet actually below the base of the tree,(the laser at your eye is 10 feet or more below the base) how can you get a horizontal in? The tree would not be measureable with this laser method in these circumstances?
Some of these seem to be re-conditioned units, £176.73 plus £23.35 is pricey enough but more reasonable. Are these Nikon lasers fairly robust, the internal instrumentation? I just wonder about how they would survive a trans-atlantic journey being shipped from the US?
With Nikon 550AS or Forestry, you don't need to know anything about trigonometry. You aim at the top, push the button, aim at the base, push the same button, and Nikon tells you the height. Also, you don't need to know the angles, although Nikon tells it in addition to the height. As Jeroen told, the function of the built-in cliometer is based on gravitation, I don't know exactly its mechanics.
Your vertical position can be below the base, between the base and the top or above the top, it does not matter, though accuracy may be a little bit better if you are situated between.
I checked the ebay site. The first seller appears to be "top-rated seller": 99.7% positive feedback (of 46554), and in addition you have 30 days return possibility. I believe a top-rated seller is able to pack the equipment properly. I also ordered my Nikon by post, though not from the US, but even if you order it from the US, it will lie most of the time on the cargo hold of a ship. Buy it now, before a hunter buys it for his purposes!
So it does not matter at all when you are on a slope above or below the tree, you just have to combine the measurement of the top and the base. When you are not able to see and hit the base, that is a problem.
Kouta, I am presuming that this is your good self in this photo, nice to put a face to a name. This is an impressive White Poplar, is it the tallest White Poplar or Poplar in Germany?
Jeroen, would you know what the tallest Black Poplar or White Poplar is in the British Isles? I thought you might have your Tree Register info handy? I have seen tall White Poplar over in Yorkshire and stood and admired it's height but I just cannot remember where it is? I saw it in passing and frustratingly now I cannot recall where it is? Jereon, your Prince Johan Friso has had a lucky escape, it has just been on the news how he was caught in an avalanche in Austria.
Grey Poplar (White × Aspen hybrid) does a lot better; the tallest is 42m at Birr (Offaly, Ireland) with another 40m at Ardross Castle in Scotland.
The tallest poplar of any in the British Isles is a Populus × canadensis 'Serotina' 44m tall at Borris House, Carlow, Ireland.
Yes, it's me in front of the white poplar. It is the tallest laser measured Populus of Europe we are aware of.
The measuring itself with a Nikon laser is not at all complicated, like Kouta wrote, you even don't need to know about a horizontal, this is all automatically calculated by the instrument itself. But it is like to explain how a computer or a car works: inside it is somewhat complicated, but you don't need to know it all to work with them.
About the tall Populus in the UK: you should buy the Champion Tree Book of Owen Johnson and the Tree Register, it is £ 22,- or become a member of the Tree Register, wich is £ 15,-.
Thank you very much for your practical information in discussion about the measurement methods. So, I will probably buy Nikon Forestry 550 laser ranger :-) It will be the best solution for me/us, I think so. The highest trees in Slovakia are officially at this time: 1. Sequoiadendron giganteum in Cifer (50 m), 2. Sequioadendron giganteum in Dolna Krupa and Abies alba in Hrdzava valley in the Muranska planina National Park (both 48 m). By the way, if you would like to have the Slovak book called Trees (in English) about interesting, rare or protected trees in Slovakia, please let me know on my e-mail: firstname.lastname@example.org Have a nice weeekend, Martin
It is great to get a new member to our "Nikon community"! Particularly from such a country with a lot of tall trees and old-growth forests. I have visited your country once, when I explored four days in the beautiful old-growth forest of Stuzica Reserve in the easternmost corner of the country. I hope I will have a possibility to make the second trip in coming years.
I guess you will see many of the "official" measurements are too high. Even taller trees than the 50-metre Sequoiadendron have been claimed to grow in some old-growth forests, up to 58 m for Abies alba. I could send you a list I have collected from literature. I hope you are interested to make measurements in old-growth forests, too.
I am sure you are able to use Nikon 550 Forestry or AS. You have to remember only some principles, like
1. When pushing the button, the equipment must not be rotated around its longitudinal axis. If it is, the result is too high. It is easy to test this.
2. Try to keep the equipment as still as possible when pushing the button.
3. Because the laser beam is relatively wide, you should point a bit above the top. Again, it is easy to test this.
4. Jeroen and Leo have tested that it is best to make 10 measurements and calculate the mean.
I know where there is a row of six big I think that they are Black Poplars in a field near a gorge. They are in a private field in a gorge at some distance so I cannot be sure of exact species but they are Poplars. I have taken photos with the farmer stood next to them feeding his pigs and using the photo height assessment technique I am getting a very tall measurement for a Poplar compared to your info. I am wary now though as there are too many problems with distortion with the photo technique, fore-shortening.
So you got your Nikon and the 45-metre London plane was actually 41 metres tall, still a great height. Excellent that you can now make laser measurements! But as you have indicated so many heights "exactly", we cannot know which ones of them are really exact laser measurements and which ones official heights from the book called "Trees".
I bought the brand new Nikon Laser Forestry Pro (the newer version of Nikon Laser Forestry 550). During the weekend I tried to measure some interesting and monumental trees by three-point measurement for the first time. It is very interesting and funny if you are shaking the hands :-))
For example: 1. the highest sequoia tree from Cifer in Slovakia - official height 50 m; according to my repeated three-point measurement has only 35,5 m; 2. the second highest sequoia tree from Dolna Krupa in Slovakia - 48 m; according to my repeated three-point measurement has only 33,7 m (both also due to lightning) and the tallest London plane tree from Sokolovce in Slovakia - 45 m; according to my repeated three-point measurement has only 41,0 m. You are right, it seems to be that some official height data are overstated. I will correct all the official height data in our database step by step.
Also I got the official answer from the State Nature Conservancy of the Slovak Republic to my request. They collect only the data from regional units (girth, height, etc.) and some measurements are performed with laser, other are estimated or by climbing (or combination of some measurement methods). All measurements are approximately only, respectively the data have been rounded.
Now I am quite curious which is the highest tree in Slovakia.
Have a nice day, Martin
I am quite sure the tallest tree of Slovakia is a Picea abies or Abies alba tree growing in a virgin forest reserve. Dobroc and Hroncokový grún are good candidate sites. I hope you have a possibility to measure there sometimes. Maybe we could even go together to measure there.
Very nice you have the laser now and your first results proove that our warnings to trust only laser and climbing measurements. Nice that you found a Platanus of 41 m, in the Netherlands till now we did not find one above 39 m.
I agree with Kouta that Picea abies and Abies alba will be the tallest native species, but it could be that some exotic Douglas fir or grand fir is even taller than the tallest Norway spruce or white fir. This is alo the case in Germany and France.
Kind regards, Jeroen