Patterns of branch growth and death in the crowns of Picea glehnii(F.Schmidt) Mast.

抄録

We investigated patterns of branch growth for sunlit and shaded trees in an even-aged plantation of Sakhalin spruce, Picea glehnii, in Sapporo, Japan, from 2013 to 2014. The number of current year (0-y) shoots produced per primary branch (those branching off the main trunk) increased with increasing relative light intensity above the primary branch (RLIpb), whereas mortality of the primary branches decreased with the vertical distance from the crown base, irrespective of RLIpb. In the lower part of a crown, the length of 0-y shoots on primary branches was significantly shorter in sunlit trees than in shaded trees. In addition, branches of the trees that were about to die also produced abundant current year shoots regardless of their shaded crown conditions. Physiological mechanisms underlying these results were discussed.