Beyond the timing of flowering: Shortening of spring flowering duration of Korean trees and potential community effects

Advanced spring flowering relative to climate change has been widely documented, but studies on flowering duration remain limited due to a lack of comprehensive data. This study analyzed phenological data (1970-2021), including first and full flowering dates of seven temperate tree species across 16 locations in Korea. Trends in flowering phenology were assessed using day of year (DOY) values, and floral seasonality was evaluated at regional and national scales. We found that full flowering dates advanced more rapidly than first flowering dates for most species, resulting in shortened flowering durations. These trends suggest potential shifts in the floral community structure, including reduced connectivity of flowering times among species with non-overlapping flowering seasons. Nationally, regional variation of flowering times across all species has significantly decreased in recent years (2010-2021) compared to the two preceding 20-year periods. The observed changes in flowering times may have consequences, such as (1) reduced pollination opportunities due to shorter plant reproductive periods, (2) decreased food resources for pollinator insects, and (3) shortened harvesting periods for migratory beekeepers. Although our analysis focused on a limited number of species, the potential impacts identified highlight the need for strategies to manage plant-pollinator mismatches for better pollination services.