Although 1917–18 saw high mortalities of previous seasons' seedlings, near-normal precipitation totals sufficed to keep the cones maturing on schedule.

Billions of ponderosa seeds hit the ground during the winter of 1918–19, to await the summer monsoon. They were not disappointed. The dry spell was minimal, with rain falling in late May and early June, and the summer monsoon arriving early and strong. Daily rainfall totals for the 2nd, 10th, and 13th of July set records for those respective days that stood for half a century or more. Seedling germination and survival rates were beyond exceptional: the seedlings were ubiquitous.

1920 and several following years were normally to exceptionally wet across the region. Enormous numbers of 1919 seedlings survived to create a regenerated forest all around Flagstaff. Gus Pearson had prayed for the perfect combination of ponderosa seed production, germination, and seedling survival; by the early 1920's, his prayers had been answered.

Today's unlumbered forest is estimated to be 50 percent or more composed of ponderosas from the 1919 seedling cohort. Largely as a result, today's forest is overly dense and therefore vulnerable to crowning wildfires and drought. So should we fear a recurrence of a 1919-sized ponderosa seed crop today?

Probably not; 1919 was unique. The enormity of that year's seedling cohort benefited from two factors that no longer obtain: widespread open space due to lumbering, and reduction of grass cover due to heavy grazing by sheep and cattle. Today's thick forest presents ponderosa seedlings with much harsher competition for sunlight and growing space.

Bill Wade is a geologist and an eight-year volunteer Interpretive Ranger with Flagstaff's NPS/USFS Interpretive Partnership. The NPS/USFS Interpretive Partnership is a unique agreement between the National Park Service and the U.S. Forest Service to provide Interpretive Ranger walks and talks in the Flagstaff area throughout the summer. Submit question for the ‘Ask a Ranger’ column to: askaranger@gmail.com

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