TU Dresden’s Forest Park Tharandt is celebrating a special anniversary this year: 20 years ago, in the spring of 2003, the North American Quarter was established on a 15-hectare site. At first, a network of paths and ponds symbolizing the Great Lakes and the Great Salt Lake, and rocks representing the Rocky Mountains and the Appalachian Mountains were created on the site. Subsequently, the first plants were installed and the public were invited to enter the new park, allowing them to follow the creation and development of the park from the very beginning.

Since then, around 40,000 trees and shrubs have been planted at 13,000 planting sites. All are native to North America, and most were collected as seeds by Forest Park staff and grown on site in the Forest Garden's greenhouse and nursery. To create the best possible research conditions, numerous individual specimens were collected from all 500 of the North American woody flora species represented to date, some of which were collected from different regions of their distribution area.

The Forest Park with its 42 quarters recreates the various forest types of North America: the coniferous forests of the West feature here in addition to the deciduous forests of the East. In each forest category, the trees and shrubs grow together in species-rich clusters, just as they do in their natural habitat. Data on this was obtained during the sampling trips and compared with descriptions in literature.

Since its beginnings, the aim of the project has been to record the growth and development of North American trees under local climatic and site conditions and to evaluate their potential uses. This applies not only to their use as timber, but also to their use in urban and street greenery, garden design, ornamental plants and even fruit growing. North American species in particular are especially suited for testing, as many are already established in Central Europe, such as the Douglas fir in forests, the American sweetgum in cities, the snowberry in many gardens and the aronia in orchards. However, there are many other species, some of which thrive in North America in climates that we may see in Central Europe as a result of climate change. These need to be found and tested.

Since the species in the Forest Park were planted in sufficient numbers and from different provenances of their distribution area, they offer appropriate sample sizes and opportunities for comparison for various studies. So far, the focus has mainly been on growth parameters: Height and diameter growth, comparisons between species and provenances, or reaction to weather conditions. By digging and drilling, it is possible to observe root development, assess the spatial extent of the root system, and thus also how they spread in different soils and their stability. In this way, researchers are also able to determine whether species can spread uncontrollably and cause damage.

So far, this data has been collected primarily as part of student theses. It will continue to be collected in subsequent years, including as part of third-party funded projects, in order to generate meaningful data over time. After the initial establishment phase of the Forest Park, the surveys began in 2010. Since then, there have been 45 Bachelor's and six Master's theses.

With Prof. Bernhard Schuldt succeeding Prof. Andreas Roloff as Director of Forest Park Tharandt in October 2022, the previous studies are to be supplemented and expanded, primarily through physiological analyses. As the number of droughts increases, one of the most urgent tasks of forest science is to support the conversion of forests to climate-resilient populations. Even if there is currently a preference for mixed woodland comprised of native deciduous trees, 20 years since its establishment, the Forest Park, with its considerable number of tree species from North America, offers ideal conditions for comparative research into the drought tolerance of tree species in temperate climate zones. For this purpose, essential tree-specific wood and leaf properties that are directly related to resistance to water shortage are recorded and described in the laboratory. In addition, the water consumption of selected trees is to be recorded using sensors installed in the trunk. These investigations are supported by measurements of the water release of the leaves, whereby access to the uppermost tree crown is possible using an aerial work platform. Drone-based measurements of canopy water conditions round off this data. Due to the worldwide increase in tree and forest decline as a result of drought, there is great international interest in understanding the drought response of trees. The Forest Park in Tharandt will be able to make a significant contribution to research on this subject.

Find out more about the Forest Park and its research in the following video: Non-native trees as a solution to climate change

Watch the following video for more about the effects of climate change on forests: What does the future of the forest look like?  

Contact:
Forest Park Tharandt / Saxon State Arboretum