Taiwania

Regulation of tree crown phenology and fruit set of Cinnamomum kanehirae Hayata, an endangered evergreen tree in Taiwan Phenological pattern of forest trees reveals climatic controls on phenophases and fruit development, hence providing key information for managing endangered species. We aimed to investigate tree crown phenology and fruit development of even-aged, dominant and codominant trees and to integrate the results with our study of wood radial growth of Cinnamomum kanehirae (Tsai et al., 2018). We conducted a 3-year ground-based observation of leaf, flower and fruit phenology. The fruit set and development were compared among 3 comparison groups: leafless inflorescence, leafy inflorescence and defoliated leafy inflorescence. The reproductive growth of C. kanehirae was present only in dominant trees. Dominant trees saw leaf flushes twice a year, while codominant trees once or twice. The overlapped spans of reproductive and vegetative growth implied resource competitions between these two phenophases and might cause fruitlet self-thinning in March and premature abortion in Autumn. Fruit development was correlated to the number of nearby ordinary leaves instead of inflorescence leaves. Reduced sunshine hours in autumn, 2011 may lead to the delayed flowering and truncated wood growing season of dominant trees in 2012. The different reproductive ability between tree social classes and the response of floral phenology to sunshine hours suggest important roles of light availability in fruit nursery.

对台湾濒危常绿树种 cinnamon kanehirae Hayata 树冠物候及果实发育的调控研究，揭示了森林树木物候模式对物候阶段和果实发育的气候控制，从而为濒危物种的管理提供了关键信息。本研究旨在探究同龄、优势树和共优势树冠的物候和果实发育，并将研究结果与我们对 cinnamon kanehirae (Tsai 等人，2018) 木材径向生长的研究相结合。我们进行了为期三年的基于地面的叶、花和果实物候观测。果实设置和发育在三个比较组之间进行了比较：无叶花序、有叶花序和脱叶有叶花序。在 cinnamon kanehirae 中，生殖生长仅存在于优势树中。优势树每年两次展叶，而共优势树一次或两次。生殖生长和营养生长的叠加阶段暗示了这两个物候阶段之间的资源竞争，可能导致三月果梗自疏和秋季早期脱落。果实发育与附近普通叶的数量相关，而非花序叶。2011年秋季日照时间的减少可能导致2012年优势树开花延迟和木材生长季节缩短。不同树社会类别的生殖能力和花季物候对日照时间的响应表明，光照可用性在果实形成过程中的重要作用。