The Deciduous Habit

In north temperate forests many trees and shrubs are leafless during the winter, and in tropical forests some species, growing in areas where there is a distinct dry season, may be leafless during the unfavourable period. In the New Zealand rain forest, which grows in parts of the country where there is no well-marked dry season and winters are relatively mild, the deciduous habit is uncommon.²⁹'³⁰'³¹ The following New Zealand conifer broadleaf forest species are or may be leafless during winter: wineberry (Aristotelia serrata)Fuchsia excorticata, the vines Muehlenbeckia australis and M. complexa, and ribbonwood (Plagianthus regius). Some forms of kowhai (Sophora microphylla) lose their leaves in the spring before flowering. However, with at least Fuchsia and Aristotelia, leaf fall is more related to temperature than to declining day length, which is the triggering factor for most northern temperate deciduous trees. Both species may be evergreen in milder latitudes.⁶³