Big Island ohia trees are now under a quarantine that limits transport and shipping in an effort to prevent the spread of a disease that has devastated thousands of acres of native forest.

Under restrictions approved by the state Board of Agriculture this week, moving ohia — including flowers, leaves, seeds, stems, twigs, cuttings, untreated wood, logs and mulch — from Hawaii island requires a permit issued by the state Department of Agriculture.

The quarantine is an interim measure that will be in place for a year, department spokeswoman Janelle Saneishi said Tuesday.

Agricultural officials said so far the ohia wilt, or Ceratocystis fimbriata, has not been found on other islands, but the total number of infested acres on the Big Isle is estimated at 15,000. More than 50 percent of the ohia trees in a 6,000-acre native forest stretching from Kalapana to Hilo are dead, state agricultural experts said.

Ohia is a keystone plant in native watershed areas, providing shade for plants like ferns and moss, which capture rainwater.

Board Chairman Scott Enright said ohia makes up about 50 percent of the state’s native forest and watershed and that the state can’t afford to lose the ohia forests. "We don’t have all the answers about how the disease is transmitted," he said. "However, the urgency to stop its spread is very clear."

The state said the quarantine also restricts the movement of soil from Hawaii island starting in January.

The delay in the soil rule is to determine whether soil is able to transmit the disease and to develop tests and treatment for the soil.

A person convicted of a violation may be charged with a misdemeanor and fined not less than $100. The maximum fine for the first offense is $10,000.

More information on ohia wilt can be found at HDOA’s website, hdoa.hawaii.gov/blog/main/reportingohiawilt.