Sugar planting,
drop in rainfall
may be linked
A Big Isle company gets an
By Rod Thompson
award for a century of compiling
weather data
Star-BulletinHILO -- One hundred years of rainfall records from a spot just north of Hilo may suggest sugar planting there caused a substantial decrease in rainfall, says C. Brewer & Co. official John Cross.
Or the records may simply show that weather can vary a lot, says Jim Weyman of the National Weather Service.
They agreed on one point: The Weather Service is grateful to Brewer subsidiary Mauna Kea Agribusiness Co. for voluntarily keeping records at Papaikou for the past 100 years.
Weyman, meteorologist in charge of the Honolulu Forecast Office, presented Mauna Kea Agribusiness with an appreciation award this week.
Mauna Kea Agribusiness actually started keeping rainfall data in 1893, said Cross, director of crop development at the subsidiary.
The company started supplying the information to the Weather Service in 1899, Weyman said.
Cross showed old record books: small, pocket-sized volumes, written in fine cursive script with an occasional extra comment such as, "Rainfall, .01 inch. Large earthquake today."
Overall, Cross found rainfall was frequently more than 200 inches per year, sometimes up to 300 inches, until about 1930. Then it dropped dramatically, only rising above 200 inches once in the next 70 years.
"Trees will call rain," Cross said. The drop in rainfall coincided with the cutting of upland forests for sugar expansion in the 1930s, he said.
Weyman agreed that cutting of Hilo Coast forests may have had an effect. But he noted that dust bowls in the Midwest were happening at the same time, suggesting a much bigger phenomenon.
Still, Cross speculated, if the cutting of forests caused rainfall to decline, will the planting of new forests for timber, under way farther north on the Hamakua Coast, cause increased rainfall?
Weyman was willing to wait and see. "Even 100 years is a short period when you're looking at the whole scale of the Earth's atmosphere," he said.
Mauna Kea Agribusiness is one of 11,000 volunteer weather observers in the United States, Weyman said.
The first one in 1644 was followed by such notable names as Thomas Jefferson, who kept records for 40 years, and George Washington, who made weather notations until a day or two before he died, Weyman said.
