Final answer:
Scientists used tree rings and pollen counts to reconstruct the climate during the Ancestral Puebloan civilization, with tree rings providing annual climate data and pollen indicating types of vegetation that signify climate conditions.
Step-by-step explanation:
To reconstruct the climate during the Ancestral Puebloan civilization, scientists have used various climate proxies such as ice cores, glacier size, ocean sediments, and specifically for this civilization, tree rings and pollen counts. Tree rings, which involve the study of dendrochronology, are particularly valuable for understanding climate patterns because they can reflect the environmental conditions each year, such as rainfall and temperature. The width and density of a tree ring can indicate the conditions under which the tree grew in a particular year. On the other hand, the study of pollen, known as palynology, helps scientists learn about the types of vegetation that existed at different times, which can be associated with specific climatic conditions. Pollen grains are resilient and preserve well in the geological record, enabling scientists to infer the climate when these plants thrived.