Thanks to their filter function and cooling effects, trees contribute signficantly to improving the microclimate in towns and cities and for this reason, their importance will only grow amid ongoing climate change. In this context, rising temperatures together with the increasing densification of cities create huge challenges for the trees themselves. "Today, urban spaces have become simply too warm for many species of trees that were considered suitable for towns and cities only a few decades ago," explained Professor Alexander von Birgelen, Professor for Planting Design at Hochschule Geisenheim University. What is more, the warmer climate and severe precipitation events expose trees to infestations of new types of pests and fungi.
With this mind, the 20th Rhine-Main Municipal Tree Maintenance Conference which took place at Hochschule Geisenheim University at the end of September 2019 centred on the topic of young trees. The focus was on the key issues that concern all municipalities: which trees should we grow in our towns and cities today? What are the basic urban conditions that we need to provide for them? How can we improve locations in order to sustain current stocks in the longer term?
As part of the anniversary conference, the speakers provided insights into the production of tree nurseries and wood inspections, reported on the integration of tree substrates and demonstrated skilled pruning techniques. Moreover, the approximately 90 participants discussed the application of professional standards and the new supplementary technical contractual requirements and guidelines for tree maintenance (ZTV). Representatives of the "500 trees for Rodgau" project showed how successful expanding urban tree stocks can be.
"In this context, networking at the regional level is of particular importance – now more than ever," said Dipl. Ing. Matthias Zorn, initiator of the Rhine-Main municipal tree maintenance working group and alumnus of Hochschule Geisenheim University. The Rhine-Main region is characterised by a largely uniform climate and is the warmest climatic region in Germany after the Rhine Rift Valley. "Therefore, every municipality in the region is struggling with the same issues brought about by climate change. These rapid changes mean that we have to make scientific evidence applicable directly in practice and discuss solutions together so that we can implement specific measures as quickly as possible," added Dipl.-Ing. Sylvio Jäckel, Head of Green Space Planning and Tree Management at the Dienstleistungsbetrieb Dreieich und Neu-Isenburg public service company.
The history of how the annual conference came into existences also demonstrates that there is a need for a relevant discussion and networking platform. Zorn set up the Rhine-Main municipal tree maintenance working group in 1999 and its numbers have grown steadily since then. At Zorn's instigation, Hochschule Geisenheim University came onboard five years ago as a "cooperation partner with the relevant expertise, organizational capacity and the right venue", and since then the working group has been provided with substantial support by the Geisenheim Institute of Continuing Education in organizing the conference and accompanying exhibition.
With its combination of scientific and practical presentations on the challenges facing the region, together with the Rhine-Main Tree Forum in Kriftel, the conference has become one of the two main communication platforms addressing the the complexities of "trees in urban spaces" in the Rhine-Main metropolitan area.