Australian Tree Fern’S Fast Growth Overgrown Ornamentals Made It Popular, Makes It a Pest
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A PROBLEM with Australian tree fern’s fast growth Overgrown Ornamentals made it popular, makes it a pest By the 1990s, it was evident Kia‘i Moku that Australian tree fern posed a By Joylynn Paman major threat to our islands and that the paradigm would shift If you’re from viewing the plant as a great looking for landscaping contribution to a instant pest that needed to be controlled gratification immediately. This was the case in creating a in 1987 when the fern was dis- tropical covered in the rain forests of look for Haleakala National Park, within your latest Kipahulu Valley in East Maui. Kaua`i landscaping By the beginning of the 1990s, - project, then planting a fast- thousands of Australian tree growing Australian tree fern ferns blanketed low elevation might appear to be a good solu- areas and threatened the pristine tion… but is it? Used by many native forests of Kipahulu. To- plant enthusiasts, Australian tree day, the species has become ferns seem to be the answer, but naturalized across the East Maui The Nature Conservancy it is the same tendency to grow Watershed and Haleakala Na- quickly that also makes them a tional Park works to stop it from In an effort to threat to our native forests and entering higher elevations and head in a posi- watersheds. Some botanists other management areas within tive direction, have even gone to the extreme of the park. some plant in- calling it one of the worst native dustry members forest invaders in Hawai‘i – and But where the wind blows and on Maui, for good reason. where the plants go, so do the Kaua‘i, and spores. Maui is not the only O‘ahu are tak- Australian tree fern (Cyathea island that has felt the effects of ing matters into cooperi) was introduced to Ha- this pest. Moloka‘i’s rainforests their own hands wai‘i prior to the 1960s for its are in jeopardy of being overrun and are adopt- ornamental traits. Its rapid by this species and the Mo- ing a voluntary growth, forty foot tall trunk, and loka‘i/Maui Invasive Species code of conduct Forest & Kim Starr (USGS) twenty foot long green fern Committee (MoMISC) is de- to stop the sale fronds attracted many in the fending its turf. MoMISC suc- and use of Australian tree fern Australian tree fern was introduced plant industry. But as time pro- ceeded in getting the one nursery within the green industry to Hawai‘i because of its ornamental gressed, this fern from northeast- on Moloka‘i to stop selling this through self-regulation. Some traits. Its rapid growth, 40-foot--tall ern Australia began to spread. species and now is stalking the members of the Maui Associa- trunk and 20-foot-long green fern Producing millions of spores plant in the district of Kalae. tion of Landscape Professionals fronds (like those in the picture each year, Hawai‘i’s tradewinds Australian tree ferns have been recently adopted these codes and below) attracted many in the plant and feral ungulates assisted in its transported throughout the state will slowly phase out the use of industry, but the plant produces millions of very mobile spores. The dispersal. Like many other inva- through the tradewinds and plant Australian tree fern and other picture at the top was taken on sive plants, it began to attack industry, allowing them to be- invasive species over time. As Kaua‘i, where residents and private Hawai‘i’s forests and water- come naturalized on O‘ahu and an alternative, they will substi- organizations are taking on the sheds. Native trees, shrubs, Kaua‘i as well. tute these invasives with other “superweed” and trying to protect ferns, lichens, and mosses that species such as the native hapu‘u native forests. are needed to capture rainfall, On the Garden Isle, residents tree fern. maintain stream flow, prevent and private organizations are of the forest, but it turns out that soil erosion and sustain a healthy battling the “superweed” head- Known to many as the “mother they are doing more harm than watershed were quickly choked on. In the early 2000s, surveys of the forest,” hapu‘u ferns live good in this instance. If you see out by this invader. were conducted to determine the up to their nickname and foster a it for sale, notify your plant pro- extent of the population. What healthy nursery for young native vider that it is a pest. And you they found was jaw- seedlings such as ‘ohi‘a, ‘olapa, can protect the forest from your dropping. Australian and ‘ie‘ie. With its silky, red- own backyard! If you have this tree fern was just brown, wool-like fiber, up to ten pest in your yard, remove it and about everywhere. It times as many native plants find dispose of it properly, ensuring was in 2005 that they their first refuge in the moist that spores are not being spread realized they needed surroundings of the hapu‘u elsewhere. By doing these sim- to take action imme- trunk. In comparison, Australian ple things, you can help keep diately to ensure the tree fern has a harder scaled Maui no ka ‘oi. For more infor- preservation of the trunk which does not harbor mation about Australian tree remaining native seedlings as well. Instead, it fern, visit www.hear.org. forests. Today, the grows quickly, reproduces at a focus is on protecting fast rate, is easily dispersed by 12,000 acres of na- the wind and animals, and makes tive forests in the its way to yards throughout the · “Kia‘i Moku”(or “Guarding the heart of Kaua‘i, state by uninformed plant enthu- Island”) is prepared by the Maui home to many en- siasts. Invasive Species Committee to demic species found provide information on protecting only on the Garden You can help stop the spread of the island from invasive plants Isle and one of the Australian tree fern by not pur- and animals that can threaten the last areas the fern has chasing and planting it in your island’s environment, economy not heavily impacted. yard. Some people might think and quality of life. Joylynn Luckily, Maui has they’re doing the native Hawai- Paman, is public relations and education specialist with the not reached this ian forest a favor by purchasing MISC. Forest & Kim Starr (USGS) extent yet. a fern that hasn’t been taken out As submitted to The Maui News. August 12, 2007. Page D9. .