Whole-tree winter leaf-loss in wineberry (Aristotelia serrata, Elaeocarpaceae) is not related to mean air temperature

Abstract

Winter leaf-loss of wineberry (Aristoteliu serruta) was measured at a range of sites in the South Island of New Zealand in early spring to investigate the temperature dependence of deciduousness in this species. The number of leaves emerged over the growing season on both shaded and exposed shoots increased with temperature across sites. There was consistently greater leaf loss from exposed shoots than from shaded shoots. Con trary to a widely held view, there was no temperature dependence of leaf loss in wineberry at the whole-tree scale. However, the difference in propor tional leaf loss between exposed and shaded shoots decreased with increasing temperature, driven by an increase in leaf loss from shaded shoots at warm sites. Causes of these patterns may be elucidated by investigations of shoot-level phenology and leaf responses to winter photoinhibition. © 2001 Taylor & Francis Group, LLC.