The ring patterns from each sample are compared in anticipation of finding identical patterns in samples that overlap, but are from trees that sprouted and were cut at different times. Once the sequence is complete, the archaeological site under investigation can be dated in reference to the exact year in which the timber was cut. In some places, such as parts of the American Southwest, a sufficient number of tree ring specimens have been collected, curated, and studied for so long that a very long dendrochronological sequence exists. This gap means that the actual dates of the prehistoric sequence cannot be determined at this time. Sequences of this nature are described as floating sequences .
Archaeological scientists deal with trees that have been cut down, and, therefore, are dead.
Foresters and other scientists concerned with the age, health, and vigor of living trees, and their productivity in terms of timber resources, also use dendrochronology, but these people do not cut down trees in order to examine the growth rings. They use a special coring device. To use an increment borer the bit is removed from and then attached to the handle. The extractor is removed and set aside. The bit lubricated with beeswax and screwed into the subject tree.