Oak seedling distribution along a long slope and acorn dispersal by Jays

To detect the gravity and animal dispersal of Oak (Q. crispula) acorns, in situ, we set 1500m long seedling transect along a mountain slope, 950-1550m alt., at Chichibu, Central Japan. We also observed Jay's (G. grandarius) acorn load behavior. Seedlings appeared in contagions along the slope and the cohort shifts in each year of the two. Jays brought acorns 500-1500 far, over a valley. The acorn movements were distict and Jay function for the oak acorn dispersal is suggested to be significant in some phases of oak population dynamics.

Key Words: Acorn, Gravity dispersal, Animal dispersal, Seedling transect, Quercus crispula, Garrulus glandarius

Annual meeting of Japanese Forestry Society, 2002