请教prep1-essay 15 No 50. ring patterns of dead trees of different, but overlappin

smilesansan

The annual growth pattern appears as a series of larger and larger rings.  In wet years rings are broad; during drought years they are narrow, since the trees grow less.  Often, ring patterns of dead trees of different, but overlapping, ages can be correlated to provide an extended index of past climate conditions.

看不懂这句话,究竟overlapping是修饰trees还是修饰pattern呢?有没有人能帮一下,谢谢

smilesansan

不好意思发错地方了,版主要不帮我转到阅读区吧