 By 1085, the Chacoans had constructed great houses at Chetro Ketl, Pueblo Alto, and Pueblo del Arroyo, during what Fagan describes as "a time of extraordinary growth and outreach".In 1983, dendrochronology of wood samples from Chetro Ketl provided information on species selected, season of cutting, wood modification and use, as well as an estimate of the number of trees required to build the great house.Trees were harvested for construction at Chetro Ketl annually, which contrasts with the sporadic patterns found at other sites in the canyon.