Open Access

Elena Wulff

• Used for public and private demand, plants are supposed to withstand the given climatic conditions in their habitat - particularly low temperatures during cold season - in order to be able to grow permanently. Since the 19th century, plant species have been assigned to different temperature zones that allow accurate determination of the specific temperature tolerance during winter. By employing a so-called winter hardiness map (a 1984 version by HEINZE & SCHREIBER is commonly used in Europe) it is possible to evaluate the winter hardiness zone of a potential planting location. Thus, the map facilitates the assessment of species-specific growing capabilities in any given region. However, in the wake of climate change in Europe, the demand for an updated map is intrinsic. This thesis aims to develop an updated plant hardiness zone map for Europe based on minimum temperature data from 1991 to 2020 which for the first time incorporates mesoclimatic effects. These effects encompass absolute and relative elevation, slope gradients and distances to the coastline. The foundation of this updated map consists of the mean annual minimum temperature (𝑡𝑚𝑖𝑛𝐽) of 11,814 metereological stations throughout Europe in a 30-year stretch. Station data was subsequently interpolated by employing the EBK Regression Prediction algorithm in the ArcGis Pro software. In previous research by the author, it was found that not only the number of stations used but also the comprehensiveness of the statistical series has considerable effect on the quality of the interpolated result. Hence, a procedure for adjusting the time periods of the statistical series is showcased and eventually applied. To ensure an appropriate usage of the new plant hardiness zone map, a grid of the standard error of the mean is added. The grid shows possible flaws of the model due to uneven data distribution and the complexity of climatic conditions.