The U.S. Forest Service used a Cessna 205 aircraft to discover that 26 million trees have died in California since October 2015. Instead of relying on satellite images or unmanned aerial vehicles, popular devices in today’s agriculture, the Regional Aerial Survey Program uses a more old-fashioned method of collecting data.

Created in the early 1960s, the Cessna 205 boasts a large cabin and a long wing stretching across the top of the aircraft. The team has been using this model since its first California studies in the early 1990s. Despite technological innovation in the form of drones and satellites, the team continues to fly the plane for its annual assessments.

The agency announced in a recent press release that this year’s survey reflected a large number of tree mortalities, catapulting the region’s total number of tree deaths to 66 million since 2010.

Starting in June and ending in September, the Forest Service’s Aerial Survey team conducts more than 150 flights to gauge the status of California’s trees. While a pilot flies the aircraft at 120 mph, sketch artists in the cockpit draw what they see on GPS programmed touchscreen tablets. When the team returns to the ground, they use Geographic Information System software to analyze their newly collected data.

Jeffrey Moore, Regional Aerial Survey Program Manager, operates these surveys, which cover more than 50 million acres. He works within a budget of $100,000. Moore relies on the Cessna over drones or satellites because drones are expensive and must be operated under strict conditions and satellites take a long time to turn around images.

“[The Cessna] method has been in use in some fashion since the very early days of aviation; in that respect, it provides historical continuity. The Cessna platform, with its high wing, affords the best views of the terrain below at slower speeds and economically, ” Moore said. “It is very inexpensive, efficient and versatile.”

Four consecutive years of drought, consistently rising temperatures, and bark beetle infestation contributed to the high level of tree mortality reflected in the survey.

“The situation is very tough for trees,” said John Heil, press officer for the Pacific Southwest Regional Office of the Forest Service. “We’ve got many more flights to do. We are definitely looking at an increase in mortality this year.”

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