The avenue of plane trees in the lower town of Müllheim is not just a jewel. It is also a valuable habitat for many animals. The masts are currently fitted with new crown anchors.
Work on the mighty crowns should be completed by today’s Friday. The trees are approximately 150 to 180 years old. But the exact age of the plane trees in the lower city is not known. What we do know, however, is that such a stately boulevard with 24 plane trees that probably dates back to the 19th century can only be found in a few places in Germany.
Many years ago, this was also the reason why the Müllheim plane trees were mapped as a whole as a natural monument and thus placed under special protection. In a brochure published by the Freiburg Regional Council, experts deal with the Müllheim plane trees from various perspectives, including the habitat potential for many species of birds and other protected animals, as well as tree care measures, which are caused, among ‘other, from the spread of the Massaria fungus, the weakened branches of the plane trees, and the corresponding risk of breaking the huge branches of the crown.
Species protection and tree care in harmony
According to the law, species protection and tree care must be reconciled. This requires proper professional support. Together with tree expert Hannes Wagner and ornithologist Frank Wichmann, these experts were at the side of the tree care company Baumpartner Breisgau.
“The necessary measures for the care of the trees were discussed in advance and coordinated with the lower nature conservation authority,” explain Wichmann and Wagner. The reason for this is the result of the annual inspection of the trees, which, among other things, concerns the spread of Massaria disease. The fungus “Splanchnonema platani” has spread on plane trees since the early 2000s. The most common symptom is a brown discoloration of the affected branches, which die along their entire length.
Close checks and regular care
A report by tree expert and regional council – appointed expert Thomas Herdt clarified the need for action on the plane tree avenue many years ago and led to the closure of inspections and regular maintenance work in order to continue to maintain the stately avenue . Now it was a matter of replacing the crown anchor. In these days up to and including Friday, around 66 steel safety devices and the same number of plastic ropes have been replaced.
The arborists of the Freiburg specialist company Baumpartner Breisgau climbed from branch to branch on the plane trees. They were supported by their colleagues in the cherry picker. The steel anchors were also replaced that year, still held in place with bolts drilled through the branches of the canopy. “That was the state of the art at the time. Today the strings are wrapped around the branches,” explains Hannes Wagner.
Shorten for less susceptibility to wind
To optimize the stability of the majestic trees, stems are shortened and rotten branches are removed. “The goal is to create a homogeneous canopy by shortening, so that the treetops are less sensitive to the effects of the wind,” explains Wagner. The plane trees are also the habitat, and not only, of a large colony of crows, which, according to the ornithologist Wichmann, has not increased for more than five years, contrary to what some local residents claim.
Numerous bats and jackdaws also live here. Both animals use tree hollows as spawning grounds, additional nesting boxes have now been hung up for the jackdaws. “Such a large population of jackdaws is extraordinary. About 30 pairs live here,” emphasizes Frank Wichmann. According to Wichmann, in consultation with the Lower Nature Conservation Authority, it was agreed that even individual crow’s nests should be removed by tree care measures that serve to ensure traffic safety if it is not otherwise feasible for technical reasons.
Preserving plantains costs a lot of money
The city of Müllheim pays a lot to preserve the plane trees, which also serve as a habitat for many different animals such as birds, bats and beetles. “The annual work alone in the plane tree avenue costs the city around 8,000 euros,” says Patrick Weichert, head of the city’s tree department. The current project, which focuses on replacing cable anchors in treetops, costs around 45,000 euros, Weichert reports. The material occupies the largest object.
In the second part of the avenue of plane trees between the intersection with Sterchelestrasse and the main road there are other plane trees that were planted around the 1960s and are much smaller. The works in the old part of the Platanenallee should be completed by this Friday.
