The Life Zone Concept


C. Hart Merriam

C. Hart Merriam

C. Hart Merriam's "Life Zone Concept" is the organizing theme behind the planters in the Museum's Jaime Major Golightly Courtyard. During his 1889 expedition to Northern Arizona, Merriam observed that the kind of plants and animals found near Flagstaff changed as a function of elevation, and proposed that the flora and fauna could be grouped into zones based on the dominant type of vegetation. Further, he argued that the vertical changes on a continental scale as one moved from south to north. Thus, our Spruce/Fir Life Zone found only from 9,200 to 10,500 feet elevation on the San Francisco Peaks, could be found at sea level in Alaska.

At the time many naturalists divided North American plants into eastern, central, and western zones. Merriam's emphasis on latitude and elevation quickly won the day. Although modern forest ecologists use a much more detailed and complex system for a forest classification, Merriam's life zones remain a useful educational tool for observing our forests. The four planters in the Museum's courtyard are organized in order of elevation.

Click below to find out more about the Courtyard's Life Zones.

Pinyon/Juniper Zone 

Ponderosa Pine Zone 

Mixed Conifer Zone 

Spruce/Fir Zone