In certain ideal sites, Saguaros can grow in stands of increased density in response to the favorable conditions. Here, in this photograph from Sabino Canyon in the Santa Catalina Mountains of Arizona, the favorable conditions once included the the presence of a large Palo Verde that served as a nurse tree for this tight “quorum” of Saguaros. The Palo Verde is long dead now that the big cacti are all grown up. The only evidence of its existence is the tangle of trunk and branches strewn about the bases of the Saguaros, along with the dense stand of cacti it helped nurture that we see today.