Chang Jui-chang, who runs the TFRI's Center for Forestry Disease Control, points out that most trees in urban green areas and on school campuses have been propagated from a small number of parent trees, and their reduced vigor and immune resistance make them vulnerable to insect attack.
林試所林木疫情中心負責人張瑞璋指出，都市綠地、校園裡的樹種，常常是從幾株母樹大量培育出來的，樹樹同出一脈，生長與抵抗力退化，讓蟲兒有可趁之機。