1.   And by studying tree rings, the researchers found that in those same years, growth of balsam fir saplings increased.

2.   But only Guyette has done systematic sampling in Missouri streams and begun a database on ancient oak tree rings.

3.   Chad Gourley, a biologist with the Nature Conservancy, counted tree rings on a sampling of the young cottonwoods.

4.   In cold years, growth slows and the tree ring is thin.

5.   Like a single tree ring lost in the dense coil that holds a life together, it hardly seemed significant as I was growing up.

6.   Mission scientists liken their strategy for exploring the layered polar terrain to the reading of tree rings or ice cores in learning about Earth.

7.   Recent advances in dendrochronology, the study of tree rings, let specialists date oak panels with the year the tree was felled.

8.   Studies of tree rings by Abrams and colleagues have revealed that red maples were rare in the uplands a century ago.

9.   Stahle is a dendrochronologist, one of a breed of scientists who have made a speciality of analyzing tree rings.

10.   The skin-deep aspects of their racial identity can be traced like tree rings to the terms used to describe them.