When the first warm days in April encouraged the people of Dassel to enjoy the fresh air, they often hiked with their children over the Kuckucksberg to the Hunnesrück.
At the beginning of the Hunnesrück pastures – where the most beautiful Trakhener horses can be seen – one can see the stump of a thick linden tree. Here, a tree was always known locally as the "Thick Linden" or "Engagement Linden." Another name was the "Bolchenbaum" (Bolchen Tree). This name is connected to a custom that has existed for many years. The young children of Dassel were told that Bolchen (Bolchen tree) grew on this tree. Whenever a walk led past this tree, the children would equip themselves with stones and clubs to knock the sweets down and throw them away. Much to the children's delight, some often fell. However, this was less due to the tree's special fruits than to the parents, who would unnoticed throw sweets (Bolchen) into the branches behind their children or had previously deposited sweets in the tree.
The name "engagement linden" probably came from the fact that older children and adolescents of that time would take walks at dusk and arrange a rendezvous with their loved ones under the tree. One can imagine that many a marriage vow was made during nighttime declarations of love, and that an engagement was subsequently declared under the romantic protection of the linden tree.