Basis for the measurements and analysis of the city climate of Wuerzburg as well as the growth and ecosystem services of small-leaved limes and black locust in the city center of Wuerzburg are 7 weather stations and 9 tree labs which were installed from November 2017 until March 2018 in Wuerzburg.
These are at the state horticulture show, Ludwigkai, Paradeplatz, Rennweg, Zu-Rhein-Straße, Rottendorfer Tor and city center Marktplatz.
In total, the following results were derived for the measuring periods of 2018 and 2019:
- The year 2018 was up to 3°C warmer than the long-term average; there were above average summer and heat days as well as tropical nights, a certain urban heat island effect is present
- Precipitation was in 2018 around 25-30 % lower than in the long-term average
- The year 2019 was in comparison with the long-termn average warmer than the average, however not as warm as the previous year 2018. Still there were several heat waves in 2019, which generated temperatures above 40°C
- Temperature and precipitation were different within the sites, also the computed UTCI index is related to the sites.
- Trees influence the cooling of the soil surface and air significant
- Cooling of soil surface and air is species-related and below small-leaved limes markedly greater than below black locust
- Dense tree canopies lead to a better thermal comfort of humans
- There are clear differences in the growth behaviour of the two tree species
- Growth of black locust was in the years 2018 and 2019 significantly higher as the growth of small-leaved limes. Compared to 2018 the growth in 2019 was higher, especially for black locust
- Transpiration of small-leaved limes is in both years higher than of black locust
- Growth and transpiration of small-leaved limes and black locust are related to their growing site
- There is a clear relationship of the total growth of the trees with the transpiration
- The water use efficiency of small-leaved limes is at sites with a higher percentage of green highest, but compared to black locust clearly lower
Example for the presentation of results (more can be found at www.klimaerlebnis.de):
