This tree is called "Kvilleken". The Kvilleken (Kvill's Oak) or Rumskullaeken, named after the closeby hamlet of Norra Kvill, is Europe's thickest oak. Like all old oak trees, the tree has a hollow trunk, so it is impossible to determine its age by simply counting tree rings.
A part of the trunk must have died off a long time ago and is currently attached to the rest of the trunk using cables, so the tree cannot collapse further. Although many trees claim to be over a thousand years old, a magical age like this is not so unlikely for this particular tree.
The total volume of this tree was calculated to be 60 cubic metres, the third largest volume of all trees (and oaks) of Sweden.
Oldest description in 1774 when Gabriel Graelius measured it's girth to 22 ells, 13.06 in meters. Unknown at which height. It was hollow at that time too and used as a tool shed.
Waldermar Bülow described it 1917, and measured it's girth to 12,75 m, unknown at which height.
Bertil Lindquist, professor in botanics estimated its age to between 750 and 950 years, most likely 850 years, in 1939 by dendrochronology near the center, and comparing growth rate with younger trees in the area with intact trunks.
1997 it was measured to 14,11 m at breast height.
The International Oak Society has recently (may 2014) published an article about the tree on her site: http://www.internationaloaksociety.org/content/mighty-oak-kvill. See also the "blog entry" at the end of the article for more actual pictures. On some browsers you don't come in, then use http://www.internationaloaksociety.org/ and look in the left colum halfway down for the article under "DENDROLOGY, The Mighty Oak of Kvill". A report about research by Swedish arborists and a group of scientists in 2013 can be found on this site: http://www.pro-natura.net/publikat-filer/Kvilleken_final_report_160514_ENGLISH.pdf
Girth growth rateThe girth was measured more than once:
|Year||Girth@1.3 m||Measurement||Girth growth rate|
|2000||14.20 m||Jeroen Philippona||-|
|2006||14.75 m||Jeroen Pater||9 cm/year|
|2014||~15.10 m||Maarten Windemuller||4 cm/year|
HeightThe height was measured more than once:
|2000-07-25||~16 m||Jeroen Philippona||Measurement method unknown|
|2014-06-26||15 m||Maarten Windemuller||Laser with Sine method (e.g. Nikon Forestry 550 laser rangefinder)|