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RedRob, à 2014-09-13 16:55:19, a dit:
Beautiful tree, how come some of the Norways remain narrow in shape and clothed with branches way down and yet others are very open and lose their lower branches? There are both types up in Yorkshire, they look quite different at times? Do they vary according to what area they originated from?

KoutaR, à 2014-09-13 18:33:32, a dit:
I believe that the main reason, why this tree has foliage almost along the whole lenght, is that its one side gets plenty of light (the tree is standing at a creek). But branching patterns of Norway spruce also vary genetically, also within a single stand.

Stephen Verge, à 2014-09-14 10:43:15, a dit:
Yes nice tree

Just wondering how the age was calculated. Norway spruces are lucky to live 200 years in U.K.. It may be that fungal pathogens may be less aggressive in continental climates with colder winters?

Stephen


KoutaR, à 2014-09-14 11:24:35, a dit:
The www-site of the park says "Ihr Alter schätzt man auf etwa 380 Jahre" = "Its age is estimated as ca. 380 years". http://www.nationalpark-saechsische-schweiz.de/der-nationalpark/naturraum/naturwald/die-fichte-picea-abies/

I am not sure but I think I saw boring traces in the trunk. It is definitely much older than 200 y. Spruce cannot attain almost 5 m girth in 200 years in Germany. The UK's climate is apparently not the best for Norways spruce. Possibly too ocean. Fungal pathogens may be one factor, indeed. "Conifers" knows more about this, I once has a short e-mail discussion with him.

Kouta



RedRob, à 2014-09-10 16:01:11, a dit:
Hello Kouta, thank you for the short article, very interesting. A graceful tree in shape, this one with branches down to near the ground. Surprising that the Cragside Nordmann is nearly as tall, 49 metres. Perhaps eventually some specimans in Wales or Western Scotland could be the tallest, there was a 2005 42 metre speciman at Bodnant Gardens where I was last week but I wasn't able to measure as the area had been fenced off with no publice permitted. We need some tree measurers from the Caucasus area on here to find trees to measure.

KoutaR, à 2014-09-10 16:09:58, a dit:
Hello Rob,

I think the UK has at least greater potential for tall Nordmann firs than the Borjomi Reserve, because of milder and moister climate. The westernmost part of the Georgian Greater Caucasus may have taller trees than the Borjomi Reserve, but the real giants are likely still further west, in Abkhasia and the Russian part.

I agree that it would be the best to get information from local forest researchers. I tried to contact one but did not get answer (not surprising).



Nordmann fir in Georgia
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KoutaR, à 2014-09-10 15:52:21, édité à 2014-09-10 15:54:41, a dit:
As most members likely know, great heights up to 85 m have been claimed for Nordmann fir (Abies nordmanniana). These super-tall firs have been reported mostly from the Russian western Caucasus and Abkhazia. I discussed Nordmann fir heights with Prof. Peter A. Schmidt, a renowned Caucasus expert. He said giant firs can be found in the western Greater Caucasus, particularly in the Russian part and in Abkhazia and he has not seen any giants in Georgia (excluding Abkhazia, which is not in Georgian control anymore). According to him, the Georgian floras and other sources give the max. height of the species as 50 m. Thus, I did not expect to find any super-tall trees in Borjomi Reserve, and the fact that the tallest tree I found was only 50.2 m http://www.monumentaltrees.com/en/geo/samtskhe-javakheti/borjomi/9778_borjomistrictnaturereserve/) is no argument against the possibility that the claimed super-tall trees exist.


While in the park, it became clear to me why there are no super-tall firs: the vegetation clearly shows that the climate is way too continental and dry for optimal tree growth. The southern slopes are covered with low forests of such drought-resistant taxa as Quercus petraea ssp. iberica, oriental hornbeam (Carpinus orientalis) and Scots pine (Pinus sylvestris). The northern slopes are moister but Scots pine is still very common, along with Caucasian spruce (Picea orientalis) and common hornbeam (Carpinus betulus); the forest floor is fairly open. Along the Georgian Black Sea coast there is a mild and moist “rainforest” strip but the fir does not grow there. As a conclusion, it remains a mystery whether Nordmann fir can really reach 70 or even over 80 m.



RedRob, à 2014-09-08 16:17:34, a dit:
Superb tree, tallest in Europe (is it the tallest in the world measured?) Great to have laser measured trees, a 30 metre Juglans Regia was reported at Glen Lyon about a decade ago but turns out to be 20 metres laser measured, another in Suffolk was 27 metres but is 24.8 metres. This one is the tallest and accurate. Always have a soft spot for Juglans Regia since a holiday in Corfu in 1977 when I was nine and there was this beautiful tree right outside the balcony which I was fascinated with because of the aroma it gave off in the heat.

KoutaR, à 2014-09-09 07:18:51, a dit:
According Prof. Dr. Hans Pretzsch (in Enzyklopädie der Laubbäume), the species reaches 35 m in forest. Such heights sound extreme to us because walnut is not(?) planted in forest stands in our countries. This is the tallest laser-measured specimen so far I know, but I have no doubt that taller ones exist. Remember that the natural area extends over the Himalayas to Japan!

A 30-metre tree shrank to 20 m after a laser-measurement - quite extreme! I have encountered 40m -> 30m.


Sisley, à 2014-09-09 18:53:20, a dit:
Very nice trip in Georgia !!

A lot of tall species.

- - -

I know that a persian walnut was found in France, in a forest near Mulhouse (Alsace/1999) and the height was around 36 m.

The method is unknow. And I don't know if he's still alive.

- - -

Did you visit the Nordmann spruces's forests ?


KoutaR, à 2014-09-09 19:13:00, a dit:
I visited one place with Nordmann firs. On-coming soon...


Note on velvet maple heights
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KoutaR, à 2014-09-07 20:39:14, édité à 2014-09-07 20:40:13, a dit:
Velvet maple (Acer velutinum) has been claimed to reach heights up to 50 m in northern Iran. The tallest maple I found in Lagodekhi Protected Areas, Georgia, was only 39.7 m (érable d'Asie (Acer velutinum) '19217').


However, the easiness of finding almost 40-metre maples and the fact that I found all the trees without any local help suggest that the species may reach well over 40 m even in this park. Moreover, the growing conditions are better in northern Iran, the winters being milder and the growing seasons longer. Compared with sycamore maple (A. pseudoplatanus), velvet maple generally seems to develop a beech-like straight trunk, which suggests a greater height potential than that of sycamore maple. Thus, my findings in eastern Georgia are no argument against the possibility that the species could reach 50 m. Ten years ago, I had the opportunity to visit some forests in northern Iran and I saw larger velvet maples there, though I cannot estimate their heights (some of my earlier estimates have proved to be totally wrong since I started to measure with a laser). I believe velvet maple is the tallest maple species of western Eurasia, but whether it really reaches 50 m remains a mystery. 50 m would be taller than the tallest bigleaf maple (A. macrophyllum) in California, which is 48.1 m ( http://www.mdvaden.com/maple_tallest.shtml).


RedRob, à 2014-09-08 16:05:27, a dit:
Hello Kouta, sounds like an exciting trip to Georgia, did you find any big Nordmann Firs on your travels? (haven't checked the main page yet so you may have posted something that I haven't seen)

KoutaR, à 2014-09-08 19:23:52, a dit:
Hello Rob!

No particularly big/tall firs. Up-coming in a few days...



KoutaR, à 2014-09-07 19:01:51, édité à 2014-09-07 19:03:02, a dit:
39.7-metre black poplar
KoutaR, à 2014-09-07 19:09:14, a dit:
I only wanted to add a caption but clicked a wrong button.

Frank, à 2014-08-06 10:41:17, édité à 2014-08-06 12:33:54, a dit:
Hello Mairie,

this is a magnificent tree, but it is no Sequoiadendron giganteum. It's a Sequoia sempervirens. And if the girth measurement is indeed correct, it would even be the largest specimen here in Europe. It sure looks like a heavy trunk. Congratulations...:-0...!

Thanks for sharing...:-)

Best wishes

Frank

RedRob, à 2014-08-06 16:13:01, a dit:
Agree totally with Frank, what a magnificent Coast Redwood, second tallest recorded in Europe at the moment. The photo with the people walking past really gives a context, a perspective of it's size. Well done for bringing this tree to light. What is the climate like In Vals-les-Bains, not familiar with this area so will Google at some point if no rely.
KoutaR, à 2014-08-07 10:36:18, a dit:
Hello Mairie,

A magnificent tree, indeed. Which instrument did you use for the height measurement?

Kouta

mairie07, à 2014-08-12 07:42:21, a dit:
bonjour et merci pour vos commentaires et compliments.

Pour la mesure nous avons utilisé la méthode théodolite à visée laser et pour la circonférence un ruban souple apposé au tronc.

Nous sommes situés dans le Sud Est de la France en région Rhône-Alpes dans le département de l’Ardèche.

Cordialement

Mairie07

Conifers, à 2014-08-14 19:29:44, a dit:
Still needs changing to Sequoia sempervirens - any objections to my doing so?
Jeroen Philippona, à 2014-08-14 20:28:59, édité à 2014-08-14 20:40:39, a dit:
Bonjour Mairie,

I hope you don't mind that I have changed the species from Sequoiadendron giganteum to Sequoia sempervirens, wich it very clearly is.

We like to have the right information on this website about species and measurements.

This specimen is extra interesting as indeed being probably the largest and second tallest Sequoia sempervirens tree in Europe we know of.

It seems to be a rival of the largest Seqoiadendron in Europe regarding to total woodvolume and could be one of the largest trees in Europe already.

Best regards,

Jeroen Philippona

Sisley, à 2014-08-15 16:58:40, a dit:
Very nice tree !!

The measures was made by personnel of the Town Hall and 'mairie 07' says that they used a theodolite, a surveying instrument.

mairie07, à 2014-09-03 09:04:44, a dit:
Merci à tous pour votre intérêt pour notre sequoia sempervirens. Je pense effectivement que ce sequoia est le second en Europe.

Les mesures ont été effectuées par une entreprise externe de géomètres experts.

Merci d'avoir rectifié sa catégorie. j'avais fait erreur lors de l'enregistrement sur le site.


KoutaR, à 2012-10-25 06:02:18, a dit:
Hi MColombari1,

Thank you for adding these trees to MT! According to the coordinates this tree seems to be located in Prašnik Special Reserve: http://www.monumentaltrees.com/en/hrv/centraleastern/brodposavina/4244_forest/

Is that right?

According to Wikipedia, Novi Varoš and Okučani are located in Brod-Posavina County, not in Sisak-Moslavina County. Do you agree?

http://hr.wikipedia.org/wiki/Novi_Varo%C5%A1 http://hr.wikipedia.org/wiki/Oku%C4%8Dani

Kouta

MColombari1, à 2012-10-25 07:03:47, a dit:
yes it is in Prasnik special reserv. And i'm wrong, okucani are located in brod-posavina.

Sorry and tank you.

Massimo

start58now, à 2014-07-29 21:15:18, a dit:
An unusual named oak tree but a very good one.

G HUber


KoutaR, à 2014-07-04 13:57:37, a dit:
Sisley,

Was this tree really climbed on 2013-06-20 and is 57,7 m really achieved by tape drop? If I recall correctly, the height was first over 58 m and you corrected it after we said the height must be measured to the average ground level, not to the lowest ground level.


Sisley, à 2014-07-04 19:12:04, a dit:
Yes he was achieved by tape drop by the team of climbers in june 2013.

My first measure was made by laser and she was wrong because the I taked the lowest point of the trunk base.


KoutaR, à 2014-07-04 19:28:08, a dit:
Thanks, Sisley!

I proposed in the case of the Oak of Ivenack (chêne pédonculé (Quercus robur) '1758') that if a tree has been measured by a reliable method (tape or laser), height measurements made by an unreliable method should not be added.

It is an equivalent case with this tree. Tape measurement has been universally considered as the most accurate and reliable method. I propose that a laser-measurement should not be added if a former tape measurement proves that the laser-measurement is inaccurate like in this case. Or is the top broken?


Rainer Lippert, à 2014-07-04 19:57:20, a dit:
Hallo Kouta und Sisley,

entscheidend bei Tape-Drop ist aber auch, wie genau der Nullpunkt unten gemessen wurde. Steht der Baum am Hang, kann das schon eine Differenz ausmachen, wenn man unten ohne genauem Messgerät den Nullpunkt bestimmt. Und auch oben können beim Tape-Drop noch Probleme auftreten, den tatsächlich höchsten Trieb zu erwischen. Karlheinz ist hier zweimal hochgeklettert:http://www.monumentaltrees.com/de/bericht/1027/

Beidemal hatten wir da die Probleme bei der Abtastung der Spitze. Also auch da kann es zu Fehlern kommen. Also nicht zwingend muss Tape-Drop die genaueste Messung darstellen. Das Equipment von Karlheinz, also TruPulse 200X auf Stativ zur Spitze und Basis, und Leica Disto D8 vom Stativ aus zur Nullpunktbestimmung, sehe ich schon als sehr genau an. Eventuell genauer als Tape-Drop, wo nicht bekannt ist, wie exakt der Nullpunkt unten bestimmt worden ist und wie sich oben die Spitzenabtastung gestaltete.

Viele Grüße,

Rainer


KoutaR, à 2014-07-04 20:21:16, édité à 2014-07-04 20:22:06, a dit:
Sisley, could you ask the measurers, how they defined the average ground level? Did they measure or estimate it? If estimated, that can really make an error, though likely not 1.4 m.

I believe it that Karlheinz had problems with measuring the top in tape measurement - one year ago he had no idea how to do that, until Michael Spraggon explained it to him.

The distance measuring of the 200X and Disto is undoubtely top-accurate, but the angle measurement not so. It may result in a ~50 cm error. We have already discussed this and the measurement gurus of NTS (Bob Leverett) have indirectly confirmed it.


Karlheinz, à 2014-07-04 20:52:39, a dit:
The sequoias in Ribeauvillé and Niederbronn I measured about one to two meters less in height than my predecessors. That surprises me a lot. I have no explanation. The measurement conditions especially at the trees '12175 'and '8217' were good. I had a clear view simultaneously to the tree top and to a marker nearby the base. The measurement was performed with TruPulse 200X on tripod.

greetings, Karlheinz


Karlheinz, à 2014-07-04 22:29:30, a dit:
Kouta, your statement about accuracy of angle measurement with TruPulse 200X and Leica Disto D8 I can not confirm. In my earlier tests both clinometers matched very accurate. The measurement accuracy of the TruPulse is rather limited by the width of the laser beam, which does not allow pinpoint accuracy aiming at small targets.

Sisley, where is your home location? Maybe we could once meet somewhere in the middle, and together measure a tall tree.

Karlheinz


KoutaR, à 2014-07-05 06:18:23, a dit:
http://www.ents-bbs.org/viewtopic.php?f=235&t=5517&start=20

Message #30 and onwards.


KoutaR, à 2014-07-05 06:33:59, a dit:
One possible explanation is that Pierron & Thomas have measured the tree to the lowest ground level like Sisley did at the beginning. Sisley, what do you think about this? Is it a usual way in France to measure trees to the lowest ground level = "low slope point"?

Sisley, à 2014-07-05 19:38:55, a dit:
Hi, all poeple !

I know that the climbers measure from the top to the middle slop point.

L.Pierron said me his method, and my first measure of the sequoia of Ribeauvillé was 58,10 m at the low trunk point.

If I subtract approximately 0,75 m to join the middle slop point we find 57,35 m.

For the mapple tree it maybe possible that the real tope was not targeted ? I know, it was not obvious to found him without the leaves, therefore with the top is more hidden.

The tallest Douglas of Ribeauvillé was measured by tape of drop, 60,5 m, I found 62 m(measure not changed in page)and I see, Karlheinz found 61,5 m. The difference is not very important.

And for the trees near Niederbronn, my results were not so good, it was the first measures with laser and I did'nt have take the middle slop point.

The more important point that I see for the mistakes, is that I don't have pattern surveyor to set against the trunk.

In many situations this object would have helped me.


Karlheinz, à 2014-07-05 22:13:50, a dit:
Last year I was in Ribeauvillé just on the go with Nikon. I had no other measurement equipment here. I did not think the readings for accurate enough to be entered into the data field for measurement. Only at the tallest Douglas of Ribeauvillé I brought a height value in the caption of the photo.

This year, I've come back, have brought my entire equipment and have done my best in the measurement. For base-determination on the slope ground I used the Leica Disto D8. As difference between low and high slope point at the sequoia of Ribeauvillé I determined 1.40 m, not much different from Sisley.


KoutaR, à 2014-07-06 08:30:53, a dit:
Without seeing the tree, I guess the difference is partly a consequence of different interpretations of the highest and lowest ground levels. On a steep slope it can make a big difference. And it is largely not up to used device but just interpretation.

In addition, the clinometer error of the 200X (max. +/-0.2° according to the user manual) may explain a part of the difference. Note that even if the device gives repeated the same angle, it does not mean the angle is correct. If my "one metre long" tape measure is too long, it gives repeated the same result but it is not correct.


Karlheinz, à 2014-07-06 10:51:02, a dit:
Kouta, I know that you think your Nikon 550 for the best instrument in the world! And I guess, Sisley also measures with Nikon, is that right? In the manual of my Nikon 550 I find no specification for clinometer error. Do you really think a manufacturer that conceals the error tolerance of his unit, has the higher quality sensor? The readings with Nikon have a greater range of variation compared to Leica and TruPulse and they are more dependent on interpretation by the measurer.

The Nikon is for our purposes certainly a recommendable device. But we should not expect any accuracy that can not give the unit. The competition between European record trees which are only a few decimeters apart is hardly to decide with Nikon.


KoutaR, à 2014-07-06 15:06:54, édité à 2014-07-06 15:08:41, a dit:
It is very clear that all the TruPulses are more accurate than Nikon. I have never denied it. But here we were comparing 200X vs. tape. Everybody can do a bit trigonometry and calculate how big height error can -0.2° error at the base and a +0.2° error at the top (the worst case) make. One could think that if the distance measurement is centimetre precise, height measuring is centimetre precise, too. I also believed so at first - for example, I wrote "Disto gives accurate distances to the nearest centimetre, so using a reference point did not decrease the accuracy" in my report about the tallest beech (http://www.monumentaltrees.com/en/report/772/). But the clinometers of these devices are simply not accurate enough for that accuracy. Karlheinz, could it be time to accept that. In Finland much cited is a statement of a former president: "the beginning of all the wisdom is the confession of the facts". And I am not speaking for Nikon, which is, of course, less accurate and less reliable. I would buy 200X, too, if it was much less than 1000€. I am ready to give 2000€ for a good camera but measuring is simply not important enough for me and has recently become still less important due to this like disputes.

Karlheinz, à 2014-07-07 09:25:34, a dit:
Tape drop as well as instrument measurements, both can be accurate or inaccurate. That depends very much on the care is measured by, how favorable are the measuring conditions in the individual case, and how accurate are the measuring devices. I can not say from the outset that a particular measurement method always results in the most accurate value. If all conditions are optimal, I would prefer the tape-drop measurement result to a Trupulse 200X measurement, presumed when tape drop it is possible to determine the residual height to treetop safely.

For Koutas presumption of an influential inaccuracy of the 200X tilt sensor there is no confirmation, not even in the forums of the NTS (ent-bbs.org). In my estimation, the fault tolerance of the TruPulse 200X is not based on the tilt sensor, but on the wide laser beam when it impinges on inclined or uneven surfaces. Who wants to know more about how I judge the accuracy of my instruments, can read about it in my article in the Bulletin of ENTS, Volume 9, 2014 "Testing Three Different Range Finder With Built in inclinometer": http://www.nativetreesociety.org/bulletin/b9_1-2/B_ENTS_v09_01&02.pdf


KoutaR, à 2014-07-07 11:50:59, a dit:
The source or "confirmation" for the tilt sensor accuracy/inaccuracy was the user manual. You once gave me this info yourself. Why I referred to the NTS forum was that you first claimed the tilt sensor error is always the same, thus the error at the treetop would counteract the error at the base. Then Bob said it implies to the mechanical clinometers only, and after that you stopped to claim that. Disto's tilt sensor accuracy is actually lower than that of 200X: -0.2°/+0.3° outside the room temperature, according to the user manual. You have not tested the tilt sensors yourself.

A wide beam is a further error source, indeed. (Yes, applies to Nikon, too.)

200X and Disto are great instruments without doubt, but they also have their limits. You once said the other measurers will hate you because you have better instruments. I don't think that is true. It is great that you have them and make accurate measurements. But it is strange that you sometimes make statements that are based on nothing being essentially "religious".


KoutaR, à 2014-07-08 07:44:11, a dit:
I found the old email of Karlheinz. The tilt sensor error of 200X is +/- 0.1 degrees "typical". Only Leica's user manual tolds how much adds low or high temperature. So this was my mistake.

RedRob, à 2014-07-08 17:09:19, a dit:
I thought that a 58 metre Sequoiadendron had been reported on here, a Scottish tree measurer called Chic Henderson recently measured the Sequoiadendron at Benmore as 56.4 metres which looked like the second tallest in Europe which I just couldn't re-find on here?

Karlheinz, à 2014-07-17 14:37:18, a dit:
Hello RedRob,

as you certainly noticed by now, we have conflicting readings. From the record sequoias in Benmore and along the Big Trees Walk Uig I miss individual photos. It seems unclear to me whether these trees can be identified on site at all. Under these circumstances, no one will take the long journey to go there and to confirm the measurements. Even from the highest Douglas firs in UK I can not find individual photos.


RedRob, à 2014-07-17 16:27:13, a dit:
Hello Karlheinz, the Sequioadendrons at Benmore were visited and re-measured a couple of months ago by David Alderman and Chic Henderson with matching Forestry Pro lasers. The Uig tree was 56.4 metres, 498cm girth, there is a photo of this tree on the TROBI site. The tree in the avenue at Benmore was 56.4 metres to the top, which was dead, 54 metres to the highest live part of the tree, 602 cm girth. The Sequoiadendron at Blair Atholl, Diana's Grove could be the tallest of all as it was 54.50 metres in 2007 with a long wispy spire tip. I believe that Chic Henderson will be visiting this at some point as he is systematically re-measuring the trees across Scotland (about to check a reputed 30 metre Juglans Regia measurement) Chic said that he might join MT so may post some photos.

Which Douglas Firs do you want photos of Karlheinz, the Reelig Glen tree and others are on here already?


Karlheinz, à 2014-07-17 23:02:53, édité à 2014-07-18 07:12:08, a dit:
Hello RedRob,

a photo from Benmore trees shows the "Avenue of Giant Redwoods." I can not identify the specific tree '1715' with the record size of 56.40 m. How can I find this particular tree? I mean, if a record tree is reported on MT, it should be described so accurately that it clearly can be located in the field without further Internet research.

The highest Douglas-fir in the UK is still the '15298 'in Reelig Glen with 66,40 m. The only photo on MT shows a group of trees. There is no photo, e.g. from the base of the trunk, that uniquely could identify this particular tree. The photo of the second highest Douglas-fir '15299' in Reelig Glen shows the same group of trees and again no individual picture of this tree. From the third highest Douglas-fir '15562' there not any photo is shown. When I am in Reelig Glen, how can I detect which is the respectively measured tree?



KoutaR, à 2014-07-10 09:18:02, a dit:
The scientific name should be: Populus 'Petrowskiana'. It is a clone, probably hybrid between Populus deltoides and Populus laurifolia.

Anyway, good that you measured it!


KoutaR, à 2014-07-10 09:23:52, a dit:
Maarten, do you measure with Nikon Forestry 550/Pro or what?

Maarten Windemuller, à 2014-07-10 12:20:06, édité à 2014-07-10 12:22:12, a dit:
Hei Kouta,

You mihgt be right. When I search the books and the Internet (f.i. USDA, Wiki sites orhttp://scholar.google.com) I see three variants: P. x petrowskiana, P. petrowskiana and P. "Petrowskiana" No doubt there will come more comments so we find the correct spelling. Then we ask Tim to change it, I cannot do it myself.

Yes, I use the Nikon 550 AS. This tree I measured from south-east side (A) and north side (B). Results A 31.60 + 1.40 =33.00 and B 32,40 + 1,80 = 34.20. Avarage = 33,60. A and B are the results of scanning the top a few times, not point & shoot, and more times pointing the foot of the tree.

Best Wishes, Maarten


Maarten Windemuller, à 2014-07-10 12:58:32, a dit:
Hei Kouta,

About the picture from 1990: I removed it and asked a member of the board of the Dendrologian Seura (DS) to discuss my question to use that foto here. I think you know DS is updating the register of giants for a new publication.

Best wishes, Maarten


KoutaR, à 2014-07-10 14:02:04, a dit:
In my opinion, we could also accept P. x petrowskiana, but P. petrowskiana is clearly wrong as it is not a species. A reason for the name confusion is that Finnish/Russian 'Petrowskiana' and North American petrowskiana seem to be different taxa. Canadian studies have shown that taxa called P. 'Petrowskiana', P. 'Rasumowskiana' and P. x berolinensis have the same genetic composition and thus are synonyms; consequently they are not believed to be clones. However, these taxa in Finland are very distinct; even I can differentiate them. The Canadian studies have used Canadian material. Apparently the material has mixed when transported from Europe, maybe by early colonizers, who know. Finnish specialists have this opinion (Pentti Alanko said something like "when you see these taxa in other countries, you immediately see something is wrong"). In Finnland they are single clones, so 'Petrowskiana' would be the best in this case.

Good that you asked DS about the image. With who are you communicating? They recently visited the Netherlands and Belgium, did you meet them there?

Yes, I know they are updating the list.


Maarten Windemuller, à 2014-07-10 14:21:10, édité à 2014-07-10 14:27:18, a dit:
Interesting facts about this tree and the differences on worldscale. I think we should follow Pentti Alanko's vision.

DS: Juha R., tree specialist at Helsinki Kaupunki. He is also in the board of DS.



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