Note the subtle false rings in the fourth ring from the left and in the fifth ring from the right. These two examples are not so obvious, but sometimes in certain tree species growing in certain environments, false rings can look just like true rings. Without training in crossdating, false rings can be problematic when attempting to crossdate tree ring patterns. False rings can usually be identified during the crossdating process. Sometimes, they can actually aid in the crossdating process if the false rings occur in numerous trees sampled from a site.
Growth is from left to right.
Note the difference in growth patterns between the four younger rings to the left and the older rings to the right. During the year in which the fourth ring from the left formed, some disturbance occurred which greatly reduced the growth rate of this tree. Perhaps a wind storm damaged the crown of the tree, thus reducing its ability to photosynthesize and produce more wood. This chronology is providing scientists new insights on climate over the past 10,000 years, especially at the end of the last Glacial Maximum. Growth is from the left to the right.