Terminal velocities and falling patterns correlate with morphology of diaspores in wind-dispersed forestry species

Key message Wing loading, diaspore type (round-winged vs. single-winged), and aerodynamic motion (autogyro vs. floater) influence the terminal velocity of wind-dispersed diaspores and falling patterns. Abstract The dispersal ability of diaspores dispersed by wind can be reflected in the terminal velocity of the diaspore. Therefore, we measured the terminal velocity of wind-dispersed diaspores in 17 major forest and urban tree species in South Korea and tracked falling diaspore patterns up to the achievement of terminal velocity using the video camera recording method. In addition, the morphological characteristics of the diaspores were measured, and their effect on diaspore terminal velocity tested. Chamaecyparis obtusa (2.66 m s −1 ) had the highest terminal velocity, whereas Picea abies (0.61 m s −1 ) had the lowest terminal velocity. Falling diaspores achieved terminal velocity through (1) the oscillating falling pattern of floater diaspores, with a constant descent velocity with minor increases and decreases; (2) the decelerating falling pattern of single-winged diaspores, with accelerating descent velocity followed by rapid deceleration to terminal velocity; or (3) the accelerating falling pattern of round-winged autogyro diaspores, with descent velocity increasing steadily up to terminal velocity. The terminal velocities of single-winged diaspores were significantly lower than those of round-winged diaspores. Although there were cases of similar terminal velocity between species in the same genera (e.g., Abies , Pinus ), there were large intraspecific differences in terminal velocity within the same genus due to morphological differences (e.g., Acer ). The measured terminal velocities could be applied in simulations for diaspore dispersal distances for forestry tree species. The present study explored the relationship between diaspore morphological characteristics and terminal velocity, and is the first to report the dispersal ability of wind-dispersed seeds of major tree species in East Asia. The findings of the present study can be adopted as key input variables in seed dispersal modeling and facilitate the establishment of natural regeneration plans and conservation of endangered species in the wake of climate change.