To gauge precipitation, they looked at tree ring widths in lower-elevation oaks, which grow faster in years with higher levels of rainfall.
而为了测定降水量，他们则对长在低海拔地区的栎树的年轮宽度进行研究，因为这些树在雨水比较充沛的年份长得更快。
When the main tree dies, the sprouts are then free to grow as full trees, forming a "fairy ring" of trees around the initial tree.
当主要的树死亡，树芽即自由地成长成大树，在原来的树周围环绕形成「仙女环」。
应用推荐