One hypothesis is that the yellowcedar decline may be caused by insect parasites, specifically the cedar bark beetle.
其中一个假说认为黄杉数量下降是由以衫皮甲虫为代表的寄生害虫导致。
2
Unfortunately, we still do not know what is killing the yellowcedar. None of the explanations discussed in the reading is adequate.
很遗憾，我们还是不知道是什么导致了黄杉的死亡。阅读部分没有一个假说可以解释其数量减少。
3
These changes have affected the root systems of the yellowcedar trees: the fine surface roots now start growing in the late winter rather than in the early spring.