The monumental oak is more than 300 years old and has a trunk of more than 5 meters in circumference. Den Dikken Eik is the thickest, and probably also the oldest tree, 300 years old, in the Meerdaalwoud.
In the 1970s, this giant's life hung by a thread when one of its branches was torn off during a storm, seriously injuring the trunk. The tree survived and is currently more vital than ever.
In 1995 the age of this tree was determined by means of a bore in the trunk. At that time 320 annual rings were counted. This means that the tree started growing in the second half of the 17th century. At that time, the forest belonged to the noble family Van Arenberg.
The annual growth ring research also shows that the tree has an almost constant annual growth of approximately 1.6 cm in circumference. This has increased somewhat in recent years, perhaps under the influence of warmer spring temperatures and better tree care. During an excursion in 1921 den Dikken Eik already had a circumference of 460 cm. In 2006 that was already 530 cm. The oaks around this giant are also a respectable size.
It is not known why this oak was given the opportunity to grow into such a monumental specimen. It may have first fulfilled a function as a corner tree to indicate the border between different (forest) plots or it had an end goal as a mill stake (straight oak trunks of approximately 3.50 m in circumference were used for this). After loss of function, it was probably later kept out of respect for its size.