Maybe looking at trees and mountains does not generate a lot of money, but people who do those activities spend plenty.
The is totaling up what people spend when they visit national parks across the country.
And the parks near us (Crater Lake, Lassen, Oregon Caves, Lava Beds, and Redwood) generate something like $143 Million dollars in economic activity. Jeffrey Denny is a supervisor at Redwood; he visits with one of the economists who performed the study.