Belgium: meeting on trees and tall beeches

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Jeroen Philippona
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Belgium: meeting on trees and tall beeches

Post by Jeroen Philippona » Wed Oct 27, 2010 8:49 am

Saturday 23rd Ovtober there was an international meeting on champion and veteran trees, for tree - specialists and tree - organisations of NW and central Europe. It was held at Wespelaar Arboretum, near Brussels in Belgium. It was organised by Christopher Carnaghan, the international representative of the Tree Register of the British Isles, together with our hosts the organisation of the Wespelaar Arboretum and the Beltrees dendrological project in Belgium. About 40 persons from ten European countries attended the meeting: from Belgium, UK, Ireland, France, Germany, Luxembourg, the Netherlands, Hungary, Poland and Switzerland. There were presentations mainly about recording veteran, monumental and champion trees and creating a register and / or a database of them as well as finding and photografing them.

Among the attendants were Thomas Pakenham, autor of the books"Meetings with Remarkable Trees" and "Remarkable Trees of the World", David Alderman, Registrar of the Tree Register, Tony Kirkham, Curator of the Arboretum at the Royal Botanic Gardens in Kew, London, as well as several writers / photographers of books on old or champion trees.

It was a very nice and inspiring meeting, meant to inform each other and talking about possibilities to have more international contact and preservation of trees.
At the end of the afternoon we visited the arboretum, still young but wit a nice collection of broadleave trees.

I took the opportunity to stay in belgium and, together with Tim Bekaert, creator of the website:, to visit a few interesting places with great trees.

A. We started with the beautiful and impressive Sweet Chestnuts (Castanea sativa) of Kasteel Schouwbroek near Vinderhoute (NW of Gent).
Three impressive and vital giants of up to 9 m girth behind the park-entrance.
See at Tim's website: ... houwbroek/ or in the book of Jeroen Pater.
Because of the fence we did not measure the trees.

B. Next place to visit was the Castle park of Enghien / Edingen in Henegouwen: ... ofenghien/. A very old park with good loamy soils and good tree-growth, so very large trees to be seen.
We saw a lot of trees and measured some:
1. Hornbeam - Carpinus betulus, Height: 33 m / 106 ft, new lasermeasured European heightrecord (the champion height tree of Ireland is 34 m, but I don't know if it was measured accurate). Girth @ 1,3 m: 280 cm, @ 1,5 m (Belgian measuring height) 273 cm.

2. London Plane - Platanus x hispanica. Height: 39,8 m (130,6 ft), girth @ 1,5 m: 508 cm. Many other plane trees of around 33 - 36 m and up to 5,5 m girth.

3. Common oak - Quercus robur - Chene "Duc Prosper" - height 31,5 m (not 40 m, as mentioned on the Bel Trees list and on Wikipedia), girth @ 1,3 m: 724 cm, @ 1,5 m 704 cm.

4. Common oak at the Golf Course - height 28,4 m, girth 756 cm.

5. Giant sequoia - Sequoiadendron gignteum - height 36 m, girth @ 1,3 m: 800 cm, @ 1,5 m: 780 cm.
Two other Sequoia's of ~ 34 and ~ 35 m tall, we did not measure the girths.
I measured some other heights: copper beech: 37,6 m; common oak: 34,5 m; common ash - Fraxinus excelsior: ~ 38 m.
We did not see the ash of 48 m wich is reported on "bell trees". Small leaved lime - Tilia cordata: 34,5 m.

C. In the Sonian Forest we visited the forestreserve Kersselaerspleyn.
The Sonian Forest (Dutch: Zoniënwoud, French: Forêt de Soignes) is a 4,421-hectare (10,920-acre) forest that lies across the south-eastern part of city of Brussels.
The forest is part of the scattered remains of the ancient Charcoal Forest. The first mention of the Sonian Forest (Soniaca Silva) dates from the early Middle Ages.
In the 18th century it was still 10.000 hectare, but parts were used to create housing and agricultural areas.
The forests are in fact plantations of European beech (Fagus sylvatica), about 75 % and Common Oak (Quercus robur), around 15 % as well as small areas with conifers and other broadleaves.

The forest is on slightly rolling areas about 300 feet above seelevel with most loamy eolian loess souls, wich are quite fertile allthough they have become more acid and were there is stagnation of watertables in some places.

The Forestreserve Kersselaerspleyn was planted with beech in 1777 after clearcut. Since 1983 it is left without forestmanagement, it is an official forestreserve since 1995. Since 2005 the reserve is enlarged to over 200 ha.
The old core reserve has nearly only beech, in the newer parts of the reserve there are also many large oaks with DBH up to 110 cm and 30 - 35, perhaps 40 m height. Of many oaks the height was difficult to measure because of undergrowth with young beech. Tallest I measured was 35,8 m, but I am sure there are taller oaks.

In the core area we heightmeasured 9 out of the 18 trees marked by the forest-researchers of INBO (Institute for Nature and Forest Research in Flanders): Peter van de Kerckhove c.s. as well as another very large beech at the border of the reserve. We did not measure more trees because of lack of time.
We had a list with heights measured by the researchers in 2000 with Forestor Vertex and in October 2010 with a Lasertech Impulse Forest Pro instument, wich costs $1,895.00 at an American website and seems to be very accurate.

In 2000 beeches were measured up to 52 m (170,6 feet) wich seemed nearly unbelievable, but we new the Forestor Vertex hypsometer works with tangential methods.

The measurements of last week by Peter van de Kerckhove gave a maximum of 49,5 m (162,4 feet), still much taller then we had measured beech in the Netherlands. Because these were with laser, I was very interested.
My measurements with Nikon Forestry 550 laser were all lower. The difference was 2,1 to 7,1 meter (7 to over 23 feet) and between 4,42 and 14,34 %! So this was very strange. It was a pity we could not do the measurements together with Peter, to see wat was the reason. After mailing with Kouta, he wrote back that the Lasertech Impulse Forest Pro works with a reflector. This you cannot put on the leaves in top, so it will work like the Forestor Vertex with the reflector at the trunk, a tangential method. This explains the difference.

In my measurements of 10 beeches all were between 42 and 45,4 meter (between 137,8 and 149 feet). So I had at least a new lasermeasured heightrecord for European Beech (Fagus sylvatica)!
The tallest measured beech at right: 45,4 m / 149 ft tall, girth @ 1,5 m: 328 cm / 10,46 ft; beech on the left: 44,6 m / 146,3 ft, girth @ 1,5 m: 402 cm / 13,19 ft.

The girth of the measured beeches was between 328 and 466 cm (10,46 and 15,3 feet) and some of them are quite massive.
Most beeches measured were neighbouring open areas were other large beeches have been windthrown in a big storm in 1990 and therefore easy to measure by laser.
The second tallest beech with massive trunk, height 45 m / 147,6 ft, girth @ 1,5 m 402 cm / 13,19 ft.
There are only few other tree species in the reserve exept for some Sycamore maple (Acer pseudoplatanus), some Hornbeams (Carpinus betulus) and a few ashes (Fraxinus excelsior). This can be explained by the planting of only beech in this part of the forest and the enormous dominance of beech in this kind of habitat in NW Europe.

Jeroen Philippona

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James Parton
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Re: Belgium: meeting on trees and tall beeches

Post by James Parton » Thu Oct 28, 2010 12:03 am


Those Chestnut trees look really ancient. Very beautiful. The European beech is so impressive. Larger and taller than it's American cousin.
James E Parton
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Will Blozan
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Re: Belgium: meeting on trees and tall beeches

Post by Will Blozan » Fri Oct 29, 2010 6:23 pm


Outstanding post! You and fellow Euro-ENTS are bring some really good confirmation of the growing prowess over there. Those beeches are incredible!

I am still appalled at the assumptions made with regard to measuring with tangential methods. The multi-thousands of dollar hypsometers only make the base line accurate to within a centimeter but the height error virtually unchanged. I know we discussed this years ago and I am glad you have been able to get some truthful and accrate numbers. I hope the sine method catches on- sounds like you have had the opportunity to extend it to some key players.


Jeroen Philippona
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Re: Belgium: meeting on trees and tall beeches

Post by Jeroen Philippona » Wed Nov 10, 2010 5:26 pm

Thanks for the compliments, Will, but we are just starting. We (Leo Goudzwaard of the forest research groupe of Wageningen University an myself) had a lot of discussion on mail about the measuring technique with the forest scientists in Belgium (Luc de Keersmaeker, Peter van de Kerckhove and others), but now they understand the difference between the Sine and Tangent methods and admit the Sine method seems to be better.
An experienced tree climber of the UK, Michael Spraggon (he measured the tallest Douglas Fir in Wales of 63,79 m in spring 2009), this winter or early spring wants to come to Belgium to climb and measure some of the tallest beeches in the Sonian Forest. After that there will probably be no further discussion about the measuring technique.


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Re: Belgium: meeting on trees and tall beeches

Post by dbhguru » Wed Nov 10, 2010 8:59 pm


Like Will, I'm very, very impressed with the progress you and Kouta are making. Our European Ents rule!! I am especially impressed with the progress you are making in winning support for sine-based math in measuring tree heights. Please keep the reports on your work coming. You and Kouta are an inspiration to us all. It is clear that the European continent can grow magnificent trees of many species.

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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