King Ludwig Oak
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| King Ludwig Oak | |
|---|---|
King Ludwig Oak (also known as Königseiche) seen from the southwest | |
Staatsbad Brückenau, Bad Brückenau, Germany | |
| Native name | König-Ludwig-Eiche (German) |
| Species | European oak (Quercus robur) |
| Coordinates | 50°18′14.2″N 9°44′43.1″E / 50.303944°N 9.745306°E |
| Height | 17 m (56 ft)[1] |
| Diameter | 26 m (85 ft)[1] (crown) |
| Custodian | Lower Nature Conservation Authority of the Bad Kissingen district |
The King Ludwig Oak (in German: König-Ludwig-Eiche, and also Königseiche, Tausendjährige Eiche, and until the middle of the 19th century, Stolze Eiche) is an oak tree[2] recognised as a natural monument in the Staatsbad Brückenau, a state-run spa and park two kilometres (1.2 mi) west of Bad Brückenau in the German state of Bavaria. The German Tree Archive counts the oak among the trees of national importance (National bedeutsamer Baum, NBB).[3]
Estimates of its age range between 370 and 700 years. The circumference of the trunk is about seven metres (23 ft). It is named after King Ludwig I, who frequented it during his numerous spa stays at the Staatsbad Brückenau. The oak has been described and depicted many times since 1780. Many domestic aristocrats and monarchs from abroad who were staying in Brückenau for the cure visited the oak.
The King Ludwig Oak stands in the Sinn river valley at the foot of the Dreistelzberg mountain, at an elevation of about 300 metres (980 ft), in Staatsbad Brückenau, Bad Brückenau, Germany.[4] Until the 20th century, the spa gardens of Brückenau surrounded the tree. Due to landscape changes it is now the edge of the park near an open space, about 10 metres (33 ft) above the Sinn. A hiking trail with information boards leads past the oak. Almost the entire spa area can be seen from its elevated position. The central spa area with the Kursaal building, the spa hotel, and the foyer, lie about 200 metres (660 ft) southeast of the oak. In between, state road 3180 runs from Staatsbad to the Züntersbach district.[5]
King Ludwig I resided at the Fürstenhof during his spa stays. Built in 1775 as the summer residence of Prince-Bishop Heinrich von Bibra, the Fürstenhof is now the Fürstenhof Palace Hotel.[5] It is about 150 metres (490 ft) northeast of the oak.[6] To the north, there is a small zoo in the old castle nursery and to the east is a herb garden. Several villas and a Protestant church were built to the west around 1900.[6]
Description
The Lower Nature Conservation Authority of the Bad Kissingen district listed the oak, known as the royal oak, as a natural monument on March 2, 1987, with the number 672-N/009.[7] The royal oak appears extremely asymmetrical in the lower part of the crown. In the past, the surrounding area served the spa guests as a place to celebrate, play, dance, and rest.[8] One hundred years ago the tree's crown had a diameter of 45 metres (148 ft). Over 100 seats could be arranged in the 1,500-square-metre (16,000 sq ft) area underneath the foliage.[9] In order not to further burden the oak, no more festivals are held there.[8] If the information in the sources is correct, it would have been the largest of all the old oaks in Germany with a crown diameter of 45 metres (148 ft). Currently, the crown's diameter is only about 30 metres (98 ft) at a height of 23 metres (75 ft), as some branches have been cut.[7]
Five branches extend horizontally on one side at a height of about four metres (13 ft) and, like other branches of the crown, are heavily mossed on the top. They lie on three iron rods and two wooden poles to relieve the pressure from their mass. The tapering trunk strives vertically up to a height of about 20 metres (66 ft). It is inclined at about 20 degrees in the direction at which most of the main horizontal branches branch off. Oaks supported by poles are extremely rare, in contrast to the drawn and supported dance linden trees.[2] The Femeiche[10] in Erle (about twelve metres (39 ft) trunk circumference), the Lenzeiche[11] near Sichertshausen (about 6.5 metres (21 ft) trunk circumference), and the royal oak are the only supported oaks of this size in Germany. A hundred years ago it still had more than ten supports and the height of its growth;[12] the trunk was still completely closed, and the crown densely branched. Six branches at about the same height formed a wreath. It is not known when the supports were first installed. King Ludwig I campaigned for the care of the oak during his spa stays in Brückenau.[13] Presumably, the first supports were installed then, the oldest description of which dates from 1838.[14]
When the longest horizontal branch at 22 metres (72 ft) broke out in the 1960s,[15] a deep gap formed in the trunk on the north side. The branch had been provided with an iron ring that was supposed to hold it together. The ring had grown into the branch until it finally burst and 84 annual rings were counted around the ingrown iron ring.[15]
The trunk is completely hollow and has a 4-metre (13 ft) high and 0.6-metre (2 ft 0 in) wide crack, which appeared after the large branch broke out. It is closed with a close-knit wire mesh.[7] Some of the supported old branches are also hollow, and the upper walls are partly missing, so they consist only of a half-shell made of bark material. In addition to the supports, the oak is secured with a crown made up of about 20 steel cables that radiate from the main axis to the horizontal side branches. It is a static crown protection in which the branches are braced to the trunk by the steel cables. The ropes are attached to threaded rods that have been drilled through the branches and lead to the partially ingrown retaining eyes that are screwed into the trunk. Since the hot summer of 2003, the previously small amount of dead wood, which is regularly cut out, has increased; the oak's declining vitality noticeable.[16]
Inscriptions

A wooden plaque with the following inscription is attached to the oak (English translation from German):
| King Oak In the shadow of this oak spent King Ludwig I of Bavaria many happy hours |
The inscription on the previous plaque read (in German):[9]
| Königseiche (die Zierde des Bades), Lieblingsplatz weiland S. M. König Ludwig I. 1818–1862 |
Trunk diameter
In 2011, the completely hollow trunk had a circumference of 6.81 metres (22.3 feet) at the point of its smallest diameter and a height of 7.11 metres (23.3 ft) at 1 metre (3 ft 3 in). In 2000, the German Tree Archives indicated a circumference of 6.68 metres (21.9 ft) at the point of the smallest diameter, and in 2001, a height of 7.00 metres (22.97 ft).[3] In 2016, the trunk had at 1.3 metres (4 ft 3 in), the height of the so-called breast height diameter (BHD), a circumference of 7.00 metres (22.97 feet) and at 1.5 m (4 ft 11 in), a circumference of 6.90 metres (22.6 ft). In 1912, it was 5.70 metres (18.7 ft) at the same height.[12] According to records the circumference has increased by around 1.2 metres (3 ft 11 in) over the past 100 years, an average of 1.2 centimetres (0.47 in) a year. This roughly coincides with measurements at the point of smallest diameter in 1991 with 6.6 metres (22 ft) and in 2016 with 6.79 metres (22.3 ft). An increase in circumference of 19 centimetres (7.5 in) in 26 years corresponds to a little less than 1 centimetre (0.39 in) per year. Because of the nutrient-poor soil substrate[8] and the supported crown, the oak grows somewhat more slowly than most of its species of comparable size, for which the annual increase in circumference is around 1.8 centimetres (0.71 in)[17] to 2 centimetres (0.79 in).[18] It grew at a similarly slow rate between 1804 and 1996, with an annual increase in circumference of 1.16 centimetres (0.46 in).[19] The largest oak is at the zoo near Ivenack. It measures over 12 metres (39 ft) in circumference, is about 800 years old, and is the strongest oak in Germany at 140 metres (460 feet), and the most massive in Europe.[20]
Age
Different information is available about the oak's age. The Lower Nature Conservation Authority estimates it to be 400–600 years old.[7] In 2000, the forest scientist, Hans Joachim Fröhlich estimated its age at 700 years[8] and the German Tree Archive in 2009 estimated it to be between 360 and 420 years old.[3] Sometimes its age is given at 1000 or even 1500 years; however, this is likely to be too high. Since the oldest wood is missing in the centre of the trunk, annual ring counting with the help of a drill core or by drilling resistance measurement using a resistograph, and radiocarbon dating is impossible.[21] The actual age can only be estimated roughly based on the size of the trunk and convention. Because of the increase in circumference of around 1.2 centimetres (0.47 in) per year over the past hundred years, the age of the oak should be set at a maximum of 500 years, provided it has not grown more slowly in its younger years than in the last hundred years because of unfavourable growth conditions. The count on a branch trimmed in the outer crown area in 2007, which had solid wood to the middle, resulted in around 300 annual rings. However, it is not known when the oak formed this branch. About 120 years ago, there was an abrupt change in the annual ring width. Since then, the annual rings are only about half as far apart from one another as before.[16]




