Abstract
Some mechanisms that promote long-distance dispersal of tree seeds by wind are explored. Winged seeds must be lifted above the canopy by updrafts to have a chance of further dispersal in high velocity horizontal winds aloft or in landscape-scale convection cells. Shear-induced turbulent eddies of a scale up to one-third of canopy height provide a lifting mechanism. Preliminary data suggest that all seeds of a given species may be viable candidates for uplift and long-distance dispersal, despite the evidence that slow-falling seeds are dispersed farther under any given wind conditions. Turbulence is argued more often and more extensively to advance long-distance dispersal than to retard it. Seeds may take advantage of 'Bernoulli sailing' to move with faster than average winds. Elasticity of branches and trees may play a role in regulating the release of seeds into unusually favorable winds. Dispersal is at least biphasic, and the study of long-distance dispersal calls for mixed models and mixed methods of gathering data.
| Original language | English |
|---|---|
| Pages (from-to) | 877-885 |
| Number of pages | 9 |
| Journal | Ecological Research |
| Volume | 16 |
| Issue number | 5 |
| DOIs | |
| State | Published - 2001 |
| Externally published | Yes |
Bibliographical note
Funding Information:We are grateful for extensive discussions with Prof. S. A. Levin, Prof. S. W. Pacala, Prof. G. G. Katul, Prof. R. Avissar, and Dr H. C. Muller-Landau. Prof. D. F. Greene gave extensive and constructive criticism of the manuscript; Ms K. S. Yamasato gathered some preliminary data to help calibrate our machinery; and Mr R. Phillips of the Princeton University Buildings and Grounds Department helped us to collect seeds directly from high in a tree. The work was supported by National Science Foundation Grant IBN-9981620.
Keywords
- Bernoulli
- Model
- Samara
- Turbulence
- Updraft