a condition in which a tree starts to die from its leaves or roots backwards, as a result of disease or pollution 枯死:由于疾病或污染,树木开始从其叶子或根部倒退的状况 The leaves of this tree show signs of ash dieback. 这棵树的叶子显示出灰烬复生的迹象。 Dieback is killing trees in many areas of Auckland. 死背正在奥克兰的许多地区杀死树木。