That is why so much wilderness in this country has been organized into national parks, so experts may correct our mistaken first impressions and explain to us that, yes, the glaciers are moving, the volcanoes are stirring, the wolves are thriving again and, no, the desert is not a dead thing. Experts do that at Saguaro National Park, two sections of desert filled with cactus and other living things that clamp against greater Tucson like a pair of highly uncomfortable earmuffs. Desert crops up abruptly at the city limits, as if to emphasize the inappropriate nature of human settlement. The saguaro further underlines the point. Forests of them in the park stand tall, a few as tall as 50 feet, a sure sign that they have been there for 100 years or more.
Saguaros begin as tiny black seeds, shed by the tens of thousands every year by each mature cactus.
The lucky ones begin life under the protective shade of mesquite or palo verde, shielded from the winter cold and intense summer heat, hidden from the birds and other creatures that would eat them. Saguaro flowers blooming in spring. They develop slowly, but they thrive most often on the softly sloping plains at the foot of desert mountains, which describes these national park lowlands precisely. A year-old saguaro seedling is a mere wisp of green. Teenagers may reach a foot tall.