Rapid 'Ōhi'a Death

Rapid 'Ōhi'a Death is a fungal disease that is taking Hawaii by storm. It attacks the 'Ōhi'a tree - an important species in Hawaiian forests and  culture.

  • 'Ōhi'a lehua, or Metrosideros polymorpha is a dominant forest tree and shrub found on all of the islands of Hawaii. It can grow in many soil types - in rich forests, rocky scrub, and new lava flows.

    'Ōhi'a leaves grow up to 3 inches in length, in opposite pairs, but are very variable. They are often shiny and oval shaped, with an obvious central vein, and slightly arched smaller veins.

    Photo Credit: Forest and Kim Starr, Starr Environmental, Bugwood.org

  • The genus name polymorpha means "many forms". This refers to the various different shapes, sizes, and flower colors of the 'Ōhi'a tree. It grows in many different habitats on the Hawaiian islands - from the coast all the way up to the mountains.

    The flowers are typically red, but can be pink, yellow, orange, and anywhere in between.

    Photo Credit: Forest and Kim Starr, Starr Environmental, Bugwood.org

  • The genus name polymorpha means "many forms". This refers to the various different shapes, sizes, and flower colors of the 'Ōhi'a tree. It grows in many different habitats on the Hawaiian islands - from the coast all the way up to the mountains.

    The flowers are typically red, but can be pink, yellow, orange, and anywhere in between.

    Photo Credit: Forest and Kim Starr, Starr Environmental, Bugwood.org

  • Because 'Ōhi'a grows in so many different locations, it can be very small, or very large. Smaller 'Ōhi'a shrubs sometimes grow less than 2 feet, while forest trees can grow to 80 or 90 feet!

    Photo Credit: T. Beth Kinsey, wildlifeofhawaii.com

  • Because 'Ōhi'a grows in so many different locations, it can be very small, or very large. Smaller 'Ōhi'a shrubs sometimes grow less than 2 feet, while forest trees can grow to 80 or 90 feet!

    Photo Credit: Joy Viola, Northeastern University, Bugwood.org

  • 'Ōhi'a is one of the most common plants of the Hawaiian Islands. Some forests are 80% 'Ōhi'a! Losing such a common species would have a wide range of impacts. One of the biggest problems would be that wherever 'Ōhi'a used to be, invasive weeds would have more room to move in.

    Photo Credit: Forest and Kim Starr, Starr Environmental, Bugwood.org

  • Because 'Ōhi'a is so common in Hawaiian forests, it is considered a very important species in riparian zones - around rivers and streams. Having healthy forests in these areas is crucial for filtering water and preventing erosion. Without 'Ōhi'a, some of Hawaii's streams and rivers could be at risk.

    Photo Credit: Joel Bradshaw, Wikimedia Commons

  • Hawaii 'akepa (Loxops coccineus)

    'Ōhi'a is a food source for lots of Hawaiian wildlife. Several species of birds feed on the fruit of the 'Ōhi'a tree, including an endangered species - the Hawaii 'akepa

    Photo Credit: Dominic Sherony, Wikimedia Commons

  • 'I'iwi (Drepanis coccinea)

    'Ōhi'a is a food source for lots of Hawaiian wildlife. Several species of birds feed on the fruit of the 'Ōhi'a tree, including an endangered species - the Hawaii 'akepa

    Photo Credit: HarmoneyOnPlanetEarth, Wikimedia Commons

  • 'Apapane (Himatione sanguinea)

    'Ōhi'a is a food source for lots of Hawaiian wildlife. Several species of birds feed on the fruit of the 'Ōhi'a tree, including an endangered species - the Hawaii 'akepa

    Photo Credit: Dick Daniels, carolinabirds.com

  • 'Ōhi'a is used medicinally by native Hawaiians. The bark and flowers can be mixed together and given to women during childbirth. The leaves are also used to stimulate appetite and to treat sore throats.

    Photo Credit: T. Beth Kinsey, wildlifeofhawaii.com

  • 'Ōhi'a is used medicinally by native Hawaiians. The bark and flowers can be mixed together and given to women during childbirth. The leaves are also used to stimulate appetite and to treat sore throats.

    Photo Credit: David Eckhoff, Wikimedia Commons

  • A traditional Hawaiian building or house is called a 'hale'. 'Ōhi'a was sometimes used for the beams and poles that support the hale - as long as they were straight enough!

    Photo Credit: University of Hawaii - West Oahu, flickr.com

  • 'Ōhi'a wood was used in boat building. Traditional canoes might have 'Ōhi'a seats and gunwhales - the rails that run up the sides of the canoe.

    Photo Credit: Joseph Dwight Strong Jr., 1884

  • Until very recently, 'Ōhi'a lehua flowers were used in lei and as part of traditional hula ceremonies. The Hawaiian people have stopped using them in some events because of the risk of spreading of Rapid 'Ōhi'a Death.

    Photo Credit: Nathan Yuen, hawaiianforest.com

  • 'Ōhi'a lehua is an important plant in the traditional culture of Hawaii. There is even a Hawaiian legend all about the tree:

    Pele, the goddess of fire and creator of the Hawaiian Islands once fell in love with a warrior named 'Ōhi'a, but he had already pledged his love to a woman named Lehua. Pele became so angry that she turn 'Ōhi'a into a crooked and stunted tree. The other Gods felt sorry for Lehua, and so they turned her into a beautiful red flower. They placed the Lehua flower on the 'Ōhi'a tree, so the two would be together forever.

    Photo Credit: Nathan Yuen, hawaiianforest.com

  • Once Rapid 'Ōhi'a Death has infected a tree, it will quickly begin to show signs of the disease. This fast moving fungus causes leaves and whole branches to die back. If you see an 'Ōhi'a tree with lots of dead yellow or brown leaves, it may be infected.

    Photo Credit: Dr J.B. Friday, University of Hawaii

  • Researchers and foresters may strip off some bark, cut off branches, or cut down the whole tree to check for Rapid 'Ōhi'a Death. These photos show the trunk of an 'Ōhi'a tree with the bark stripped off, and a cross section of a piece of 'Ōhi'a wood. Both are showing typical symptoms of Rapid 'Ōhi'a Death - black staining of the sapwood where the fungus has moved through the tree, blocking off its supply of nutrients and water.

    Photo Credit: Dr J.B. Friday, University of Hawaii

  • Researchers and foresters may strip off some bark, cut off branches, or cut down the whole tree to check for Rapid 'Ōhi'a Death. These photos show the trunk of an 'Ōhi'a tree with the bark stripped off, and a cross section of a piece of 'Ōhi'a wood. Both are showing typical symptoms of Rapid 'Ōhi'a Death - black staining of the sapwood where the fungus has moved through the tree, blocking off its supply of nutrients and water.

    Photo Credit: Dr J.B. Friday, University of Hawaii

  • To get a positive identification of Rapid 'Ōhi'a Death, researchers will take samples of diseased portions of a tree to a lab and culture them. Culturing is when fungus or bacteria are grown intentionally, like in the petri dish pictured here.

    Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • After culturing, the petri dish can be placed under a microscope. Getting up close and personal like this is the most accurate way to identify a fungus. 

    Photo Credit: Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org

  • Rapid 'Ōhi'a Death kills quickly! Once a tree is infected, it can be killed in only a matter of weeks. This short disease cycle makes it very difficult to control - once a tree has Rapid 'Ōhi'a Death, it will almost certainly die.

    Photo Credit: Dr J.B. Friday, University of Hawaii, cms.ctahr.hawaii.edu/rod

  • To date, Rapid 'Ōhi'a Death has only been detected on the big island of Hawaii. There, at least 50,000 acres of forest are showing symptoms of the disease.

    How big is 50,000 acres?

    Honolulu: 65,397 acres

    Washington D.C.: 43,700

    Manhattan: 14,720

    Photo Credit: Dr J.B. Friday, University of Hawaii, cms.ctahr.hawaii.edu/rod

  • Some forests have lost 90% of their 'Ōhi'a trees in only 2-3 years.

    Photo Credit: Dr J.B. Friday, University of Hawaii, cms.ctahr.hawaii.edu/rod

  • Since 2014, researchers at the University of Hawaii and the US Forest Service have been tracking where Rapid 'Ōhi'a Death has been found. They expect that all forests on the Island of Hawaii now contain the disease.

    Photo Credit: Dr J.B. Friday, University of Hawaii, cms.ctahr.hawaii.edu/rod

  • Moving plants around is a big problem! The Animal and Plant Health Inspection Service (part of the USDA) is on the look out for invasive plants and pests like Rapid 'Ōhi'a Death.

    Slowing or stopping the spread of Rapid 'Ōhi'a Death is the main control strategy right now. The USDA has quarantined the Big Island of Hawaii - nobody may take any of the following off of the island:

     

    X  'Ōhi'a plants

    X  'Ōhi'a plant parts - including flowers, leaves, seeds, 

         stems, twigs, cuttings, untreated wood, logs, mulch, 

         green waste, or any insect frass

    X  Soil

    Photo Credit: USDA APHIS, usda.gov

  • The University of Hawaii and the US Forest Service have set up these boot brush stations. Rapid 'Ōhi'a Death can move around in the soil stuck on the bottom of your shoes! Anyone who has been in an area with Rapid 'Ōhi'a Death should make sure to remove as much mud and soil as possible. This includes cleaning soil from car and bicycle tires.

    Photo Credit: Dr J.B. Friday, Unviersity of Hawaii

  • Any tools used to cut or prune 'Ōhi'a should also be cleaned. This can be done with rubbing alcohol or bleach mixed with water.

    Photo Credit: Joseph O'Brien, USDA Forest Service, Bugwood.org

  • 'Ōhi'a firewood should not be moved around on Hawaii, or between islands. This is a good practice to keep in general. Many invasive insects and diseases have been spread long distances  by people moving firewood.

    Photo Credit: University of Hawaii at Manoa, flickr.com

Scientific Name: Ceratocystis fimbriata

Description: Rapid ʻŌhiʻa Death is a fungus that attack the ʻŌhiʻa tree (Metrosideros polymorpha), which is native to the Hawaiian Islands. Symptoms of the disease include yellow and brown leaves, dieback of branches, and a dark staining of the sapwood of the tree.

Range: Currently, Rapid ʻŌhiʻa Death is only found on ʻŌhiʻa trees on the Big Island of Hawaii.

Native Range: The fungus that causes Rapid ʻŌhiʻa Death is found on many other crops around the world – it was transported to Hawaii, likely on an agricultural product.

Habitat: ʻŌhiʻa trees grow in almost all of the different ecosystems in the Hawaiian Islands – from the coast all the way up to the sides of volcanos.

Host Trees: In Hawaii, the only know host tree is ʻŌhiʻa – but it’s an important one! Some Hawaiian forests are 80% ʻŌhiʻa! It is the most common plant on the Islands.

The Facts: Keeping Rapid ʻŌhiʻa Death contained to the Big Island of Hawaii is the current management goal. A quarantine has been put in place to stop anyone from moving parts of the tree around or off the island. The disease kills very quickly compared with other fungal diseases – some trees die within weeks or months of infection. It can be transported on parts of the tree, soil from around infected trees, and even on tools and the bottom of your feet!

The ʻŌhiʻa tree is a very important part of the culture of native Hawaiian Islanders – being used in traditional medicine, as wood for traditional buildings and boats, and the flowers are used in lei as part of hula ceremonies.