Extension
forester J.B. Friday speaks for the trees. Right now, it’s the ‘ōhi‘a (Metrosideros
polymorpha) that need his advocacy, due to a devastating new disease that’s
decimating forests on the Big Island. Rapid ‘ōhi‘a death (ROD) is estimated to
have killed mil-lions of trees over 50,000 acres in the Puna, Hilo, Kā‘ū, and
Kona districts. These iconic trees make up 80% of the native canopy of forests
in the Islands and are an essential part of a complex system of other plants,
insects, and birds, including native and endangered species.
The
disease is dramatic. Affected trees die within weeks or even days once they
start showing symptoms. Crowns turn yellowish and then brown, while infected
wood is streaked with black and, interestingly, smells like bananas. The
fungus causing the disease, Ceratocystis fimbriata, is a well-known
pathogen worldwide, and other strains have infect-ed sweet potato and taro in
Hawai‘i for decades, but the strain causing ROD is unique.
Along
with fellow members of the “ROD Squad” Dr. Flint Hughes of the USDA Forest
Service and Dr. Lisa Keith of the USDA ARS, Dr. Friday is working to increase
knowledge about, funding for, and awareness of ROD. The three were honored by
the Hawai‘i Invasive Species Council for their work against the disease. Dr.
Friday also worked to pass House Bill 1597, which funded the Hawai‘i Department
of Agriculture to address it, and lent his expertise to a crowdfunding campaign
from UH’s Lyon Arboretum that raised more than $50,000 to collect and bank
seeds from different varieties of ‘ōhi‘a—they can be endemic to a single
island—for testing for resistance to ROD and future reforestation efforts.
Researchers
are still learning about what’s spreading the disease. A possible vector could
be beetles that bore into infected trees and create spore-bearing sawdust,
which can blow into nearby uninfected stands. Dr. Gordon Bennett and Dr. Curtis
Ewing of CTAHR’s Department of Plant and Soil Sciences are setting traps for
the beetles to look for fungal contamination and testing wind currents for
infected sawdust to see if the disease is moving this way.
ROD
could also be easily spread by people moving infected wood for firewood or
posts. For that reason Dr. Friday emphasizes that the most important way to help
contain it is not to move any ‘ōhi‘a materials or soil around the trees, and he
was instrumental in supporting a new HDOA quarantine restricting movement of ‘ōhi‘a
off the Big Island. Some good news is that the disease hasn’t been reported on
any of the other islands or in the Hāmākua or Kohala districts.
More
good news is the outpouring of concern and support from a wide range of
individuals and institutions concerning the disease. “ROD is one environmental
issue where everyone is on the same side,” says Dr. Friday. “We have had
amazing collaboration and support from federal and state agencies, non-profits
and foundations, elected officials, Hawaiian cultural practitioners, and
community members. No one wants to lose the ‘ōhi‘a forest.”
Visit www.RapidOhiaDeath.org for more information.
Also see:
story from UH News
.
