ABSTRACT
Mrs. Francis reads an article about how archeologists use a research method called dendrochronology to determine when cliff dwellings at Mesa Verde, Colorado, now abandoned and in ruins, were originally built. She discovers that the process involves taking a cross-section sample from timbers used in construction. Using the distance between tree rings, archeologists identify the climatic pattern in the years leading up to the time the tree was cut down, presumably for construction of the home. Comparing these tree ring patterns to core samples taken from living ancient trees located nearby, they search for a similar series of wet and dry years. Once they fi nd a match they can state, with some authority, what year the tree that was used in the construction of the home was harvested and, by implication, the year the cliff dwelling was built.
