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Biogradska Gora – two new broadleaf tree height records

PostPosted: Sat Nov 17, 2012 12:41 pm
by KoutaR

The virgin forest reservation (16 km²) of Biogradska Gora National Park, Montenegro, consists of a mountain valley and surrounding mountains (up to 2117 metres). There is a small lake, Biogradsko Jezero, at the valley bottom (elev. 1100 m).

Biogradsko Lake. Biogradska Creek valley, where the other photos have been taken, is in the right center, towards the mountain top.

Soils are acid as they are underlain by silicate metamorphic rocks instead of limestone which dominates much of the western Balkans. Annual precipitation is quite high, approx. 2 200 mm. There is no drought period despite the Mediterranean rainfall distribution, with most rain falling outside the growing season. The forest in this park is one of the few true old-growth forests remaining in Europe outside Russia and Fennoscandia. The area has been protected since 1878, when the forest was already old.

The tree flora consists mainly of species common in Central Europe. The most common tree species are European beech (Fagus sylvatica), European silver fir (Abies alba) and Norway spruce (Picea abies), on the valley bottom and around the lake also sycamore maple (Acer pseudoplatanus). At the end of the lake around the delta of an inflowing creek (Biogradska Rijeka), there is lush moist forest composed mainly of European ash (Fraxinus excelsior) and grey alder (Alnus incana), with leaf butterbur (Petasites hybridus) dominating the understorey.

Moist grey alder dominated forest. Also sycamore maple, center, with scaly bark, and an ash sapling, left foreground. Leaf butterbur in the understorey.

Between this moist forest and the lake there is a still wetter area, seasonally flooded each year, with stands of white willow (Salix alba). Other tree species include Norway maple (Acer platanoides), wych elm (Ulmus glabra), large-leaved linden (Tilia platyphyllos) and goat willow (Salix caprea). According to the national park information, 86 tree species have been found in the park but this is a translation error: they mean woody species including shrubs.

Kouta explored this park in 2008 but without a rangefinder or even a tape. His recollections about tree heights were not very good. He thought the trees he saw were not extremely tall but we found in this park two new height records. They are: sycamore maple 40.6 meters (133 ft., this tree was dead but still standing) and wych elm 40.4 m (133 ft.).

This is Jeroen's photo. 40.6-meter sycamore maple. The other mossy trunks are also sycamore maples. Also beech, right, silver firs, left background, and hazel (Corylus avellana), the shrub left from the big maple. Wild garlic (Allium ursinum) covers the ground.

40.4-meter double-trunked wych elm. The second trunk to right backwards. Also silver fir, left, and ash, right. Biogradska Creek is behind the firs.

We also found a 39.2-meter (129 ft) large-leaved linden which was the height record at the time, but after our trip a 41.6-meter (136 ft) large-leaved linden has been found in France by a French measurer. The tallest tree we found was 59-meter (194 ft.) Norway spruce. It is not located on the valley bottom but on a lower NE facing slope. It was noticed as a tree top emerging above other trees.

This is Jeroen's photo. 59-meter Norway spruce, top left. To the left from it: silver fir. The conifers to the right from the tallest spruce are also Norway spruces. Also sycamore maple, right.

The thickest tree was the biggest spruce Kouta found in 2008. The photo below is from Kouta’s 2008 trip.

The largest Norway spruce. Silver fir foliage, right.

Its circumference at different heights:
At 1.3 m: 671 cm
At 1.5 m: 631 cm
At 2.2 m: 503 cm
At 2.6 m: 480 cm (above the buttresses)
We estimated its volume as 40-50 cubic meters. Kouta had originally thought it was not very tall, but it was actually the third tallest tree we measured in Biogradska Gora, 56.2 m. Below it from another perspective.

Jeroen admires the largest Norway spruce. The other big Norway spruce, left center, is 56.0 m tall and 540 cm around. Also beeches (pale trunks) and sycamore maples (mossy trunks). The conifer saplings are silver firs except the nearest one, which is Norway spruce. Biogradska Creek is behind the big spruces.

The second tallest was also a Norway spruce, 57.2 m. 54-55 m tall spruces were quite common. The tallest silver fir, we measured, was 53.6 m (176 ft.). We estimated its volume as approx. 35 cubic meters.

53.6-meter silver fir. Other trees are silver firs and beeches.

We explored a good proportion of the valley bottom but as the tallest tree was growing on a slope there are good chances a more thorough exploration would reveal still taller trees, at least conifers.

The Biogradska gora part of Michael's travelogue can be read here:

Kouta, Jeroen & Michael

The tallest reliably measured sycamore maple is now 41.5 m (139 ft) tall: ... lle/12183/
The tallest reliably measured wych elm is now 44.0 m (144) tall: ... ten/28651/

Re: Biogradska Gora – two new broadleaf tree height records

PostPosted: Sat Nov 17, 2012 4:09 pm
by Will Blozan

Excellent finds! I do hope you all can scout for more tall Picea and Abies as well. Beautiful site!


Re: Biogradska Gora – two new broadleaf tree height records

PostPosted: Sat Nov 17, 2012 7:16 pm
by KoutaR

I do hope it particularly for Abies alba. We think we haven't yet found the full potential of the species. I will return to this topic in the near future.


Re: Biogradska Gora – two new broadleaf tree height records

PostPosted: Sun Nov 18, 2012 7:07 pm
by Jeroen Philippona
Here is an attached list of the height- and girthrecords we found at our visit to Biogradska Gora.
Of several species we saw in the reserve (like Salix alba, Alnus incana, Acer platanoïdes and Quercus petraea) we did not make good measurements, so they are not included.


Biogradska Gora-Tree-list2012.doc
Biogradska Gora tree list
(45 KiB) Downloaded 99 times

Re: Biogradska Gora – two new broadleaf tree height records

PostPosted: Wed Jan 23, 2013 12:57 pm
by KoutaR
This is a question to all dbh and volume gurus of NTS. It is about the biggest spruce of this park (pictured above). We estimated its volume as 40 cubic meters quickly in our head (actually in Michael's head) at the tree. Now we think the estimation may be too low. We made the estimation assuming conical form, but old trees often have more parabolical form. If we use the circumference above the buttresses at 2.6 m (480 cm) as the base of a 56.2m tall paraboloid, we get 52 m3. When we add a few cubes for the buttresses and the branches we end up in almost 60 m3. Probably the real volume is somewhere between the conical and the parabolical estimate.

My question: How would you estimate the volume from these numbers and assuming the top is intact and the tree has a form similar to the American conifers familiar to you?

Height: 56.2 m
Circumference at different heights:
At 1.3 m: 671 cm
At 1.5 m: 631 cm
At 2.2 m: 503 cm
At 2.6 m: 480 cm (above the buttresses)

We know that more measurements are needed for a good estimation, so this is rather a best guess than an estimate.


Re: Biogradska Gora – two new broadleaf tree height records

PostPosted: Thu Jan 24, 2013 1:31 am
by edfrank

I have mentioned before the idea of Percent Cylinder Occupation.  he percent cylinder occupation listing is a measure of what percentage the measured volume of the tree represents compared to a cylinder equal to the circumference breast height (CBH) of the tree times the height of the tree. Trees with a fat base or a trunk that quickly tapers scores low on the list, trees that taper more slowly have higher values. Those trees with broken tops will have anomalously high values.  The table is not complete as it only lists a few of the largest species of western tree. The Sugar Pine and Western Hemlock are smaller than a number of other species, but were included as they are comparable to Eastern White Pine and Eastern Hemlock.


Looking at your numbers, the cylinder would be 4.8 meters in girth x 56.2 meters tall
radius = 0.764 m
cross section area  = 1.833 meters2
cylinder volume = 103.4 meters3

The average for the hemlocks, comparable is size is 40.9%, ignoring the anomalously low values for the other species for the other species, you have a percentage of 39.6% for 7 species.  

So my best estimate, for volume would be 40% x 103.4 m3 = 41.36 m3

This is somewhere between the volume of a cone (33.3%) and a paraboloid at (50%).

So this would make the tree somewhat smaller in volume that your estimates.  If you just look at the 5 largest volume hemlocks, their average is 44.84% which would be a volume of 46.36 m3.  

None of these calculations are including the material in the basal buttress where it is wider than cylinder radius of 0.764 m nor fro any of the branches.  

Edward Frank


Re: Biogradska Gora – two new broadleaf tree height records

PostPosted: Thu Jan 24, 2013 6:28 am
by KoutaR
Thanks Ed! Our original estimate including buttresses and branches was 40 m3, so your estimates are about 5-10 m3 larger if we add a few cubes for buttresses and brances. But the percentages are for cylinders whose radii has been derived from CBH, not from girths at heights above the quickly tapering parts of the bases. I suppose the hemlocks also have basal buttresses or otherwise swollen or widened bases, though proably not so large as our spruce?  Should we use the CBH (6.71m) or some value between the CBH and 4.8m (like their mean) also for the Biogradska spruce? Above 2.6m (girth 4.8m) the spruce has almost no taper.


Re: Biogradska Gora – two new broadleaf tree height records

PostPosted: Thu Jan 24, 2013 10:58 am
by edfrank

The basal buttresses extend up higher on some trees than others.  It is my impression, perhaps Will or Jess will comment, that the data for the hemlocks is generally above this basal buttressing.  So a similar value should be used for your tree.  The 480 cm values seemed the best choice of your data points.  The numbers used for the western trees may be suspect because I a unsure where the measures were taken with respect to this basal buttressing.  They were simply pulled from Bob Van Pelts book of Forest Giants.  

This is the data we have.  It was not collected for the purpose of these calculations and is therefore not ideal.  The numbers are for the most part pretty consistent and I would expect much more variation if some included much more of the basal buttressing than others.  I know from around here that the basal buttresses do not extend very far up the hemlock trunks, so I think the numbers generated are reasonable.  Will talks about the processes used for measuring these big hemlocks ... tocols.htm


Re: Biogradska Gora – two new broadleaf tree height records

PostPosted: Thu Jan 24, 2013 8:51 pm
by Michael J Spraggon
So my mental arithmetic wasn't too bad after all!

Those giant old growth trees at the bottom of the list would certainly have cylinder occupations far above 33% if you assume that they were approximately conical when they first reached full height. I would not be surprised if the CBH was taken at a height where the trunks were flared or buttressed.


Re: Biogradska Gora – two new broadleaf tree height records

PostPosted: Thu Jan 24, 2013 9:37 pm
by edfrank

Definitely the lower values in these trees reflect a flaring base rather than the general shape of the tree.  The value is only useful if girth is taken above the inflated base, or the resulting cylinder will be too large, and the occupation percentage will be too low.  It is an idea I proposed several years ago when first looking at general shape of the trees based up the tsuga search data Will had collected.  It was never pursued aside from a few calculations from miscellaneous data.  I think it is a worthwhile idea as it can be used to roughly estimate the volume of a tree with limited data.  There is still a range of possible volumes.  I think the 40% or so of the cylinder volume is a good first approximation for old growth big trees.  It is applicable to trees that essentially have a single trunk that extends from the base to the top.  I don't think it will be useful for broad crowned deciduous trees whose trunks split into numerous side branches as they approach the top.

Edward Frank