Aerobiological Pollen Deposition and Transport of Fraxinus excelsior L. at a Small Spatial Scale

The ongoing fragmentation of ash populations due to dieback requires an effective gene flow between individuals; thus, investigations on pollen transport are essential. In this study, comprehensive aerobiological field experiments at two seed plantations in Baden-Württemberg were conducted 2019 and 2020 order study the influence phenology meteorology (especially wind) using self-constructed gravimetric traps located 1.5 5 m a.g.l. Our main objectives investigate local scale dispersion evaluate recommended distance (i.e., 400 m) from other trees according German Forest Reproduction Act. results showed a link meteorology, onset phenological development, topography plantation. plantation Schorndorf was characterized by slope associated cold air flows, suggesting that could be factor contributing higher levels downslope traps. addition, many cases, cardinal direction with highest impaction also identical predominant wind direction. Analyzing data for single detail, we found total catch (31%) measured outside 2019, year very low flower development. contrast, most (33%) caught within 2020, which presented much stronger than (with 11 regarding sums). This indicates, lower year, potential contribution plantation, thus it can harvesting should preferentially take place full mast years. Interestingly, deposition Emmendingen height little difference compared height, but there large temporal pointing vertical variations availability. general, transported larger m, amount decreased substantially increasing distance. At 200 already approx. 50% less captured air. However, even 500 more 10% still captured. ensure cross-pollination healthy trees, individuals or stands not too large, no spatial separation (e.g., conifer stands).