鉴于英语阅读的重要性，本文从几个方面整理了托业考试阅读素材整理，希望大家可以认真阅读以下内容!
What Do They Do?
1、Read the patterns of wide and narrow rings in wood from different trees. They match patterns from different trees to identify the year that a tree produced a particular ring. This process of matching across specimens is "cross-dating."
2、Estimate archaeological ages. Andrew Ellicott Douglas was the first dendrochronologist. He became famous for his studies of Pueblo ruins, which he analyzed by cross-dating, the tool that he developed as his "key to prehistoric chronology."
3、Predict future drought, flood, and other conditions. A. E. Douglas proposed that tree rings would be allow us to measure past climate and, potentially, to predict drought and flood over a period of years, which would provide economic advantage.
What Causes Variations in Tree Rings?
When conditions encourage growth, a tree adds extra tissue and produces a thick ring. In a discouraging year, growth is slowed and the tree produces a thin ring. Much of the variation in tree rings is due to variations year-to-year in:
1、Higher springtime temperature. If spring starts early, the growing season is likely to be longer than usual, causing a tree to have a wider ring.
2、Lower springtime temperature. A late spring is likely to shorten the growing season, causing a tree to have a narrower tree ring.
3、Abundant rainfall increases growth, producing a wider ring.