Tree strategies of sprouting new shoots : why do trees have different ability of sprouting?

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To examine the site and age dependency in the ability of sprouting new shoots for tee seedlings, naturally growing Quercus crispula seedlings were experimentally cut and monitored. Total non-structural carbohydrates(INC), as the resource for sprouting, were also measured. Although this species can establish considerably under wide range of light condition, sprouting ability differed among microhabitats : Q.crispula easily sprouted at open sites, coinciding with large amount of TNC in its root.To investigate seasonal dynamics after a disturbance was investigated for Quercus serrata, the most common oak tree in temperate regions, Japan, that has high sprouting ability. Cutting experiments were carried out in May, June, Jury and August for three-year old Q.serrata seedlings and shoot recovery process was investigated with dynamics of TNC in roots. For intact seedlings, above ground biomass strongly correlated with structural part of roots rather than whole root biomass, suggesting TNC had a function that was not directly related to the ordinal growth. After the cutting, almost seedlings sprouted new shoots during the first month, and its dry mass could be explained with the root TNC at the time of cutting, indicating the high content of TNC is for shoot recovery after disturbance. Although recovery rate in biomass depended on the cutting time and light condition, all seedlings tended to complete recovering root shoot ratio to the intact level at the end of the season, and TNC restoration was also finished for the seedlings cut in May or June.