Likewise, in areas where trees grew in marginal conditions such as aridity or semi-aridity, the techniques of dendrochronology are more consistent than in humid areas.
These tools have been important in archaeological dating of timbers of the cliff dwellings of Native Americans in the arid Southwest.
These patterns can be compared and matched ring for ring with trees growing in the same geographical zone and under similar climatic conditions.
Following these tree-ring patterns from living trees back through time, chronologies can be built up, both for entire regions, and for sub-regions of the world.
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