Asynchronous leaf expansion and shedding in a seasonal environment: Result of a competitive game

A game model was developed to analyze the difference in the timing of leaf expansion and shedding among trees co-occurring in single forests in a seasonal environment. It was assumed that the photosynthetic rate of a tree is affected by the shading effect of its neighboring trees and by the seasonal change in environmental factors.The analyses showed that, if the photosynthetic rate of the tree concerned does not take an unfavorable turn due to the leaf expansion of its neighboring trees, all the trees expand their leaves at the same time when the photosynthetic rate and the maintenance cost balance. However, if the photosynthetic rate of the tree takes an unfavorable turn due to the leaf expansion of its neighboring trees, timing of leaf expansion does not synchronize among trees; instead leafing occurs continuously from the time when the photosynthetic rate and the maintenance cost balance under no-shading by the neighboring trees to the time when these factors balance under full-shading by neighboring trees. In turn, at the end of the growing season, if the photosynthetic rate of the tree does not take a favorable turn due to the leaf shedding of its neighboring trees, all trees shed their leaves at the same time when the photosynthetic rate and the maintenance cost balance. However, if the photosynthetic rate of then tree takes a favorable turn due to the leaf shedding of its neighboring trees, timing of leaf shedding does not synchronize among trees; instead shedding occurs continuously from the time when the photosynthetic rate and the maintenance cost balance under full-shading by the neighboring trees to the time when these factors balance under no-shading by the neighboring trees.