Why is the Australian Tree Fern (ATF) an Invasive Species?
Australian tree fern (Sphaeropteris cooperi) is an invasive species in Hawai’i, scoring a whopping 16 on the Hawaii Pacific Weed Risk Assessment. This ornamental plant has escaped cultivation and is considered invasive for a variety of reasons. It outcompetes native plants in the forest by growing faster and taking up valuable canopy space. It can also easily spread through tiny dust-like spores that are found underneath its fronds. These spores are readily taken up by the wind or animals and can be dispersed as far seven miles from the original parent plant location.
How to quickly identify ATF?
Australian tree fern (ATF) is an expert at camouflage because it is commonly mistaken for a variety of different native tree ferns. Hāpu’u is the common Hawaiian name for a few different species of tree ferns that are native to Hawai’i. There are many differences between ATF and the different types of Hāpu’u but the quickest way to identify is by looking at the “crown” of the tree fern (the top of the tree fern where new fronds emerge) and checking to see what color the hair is. If it is white/ silvery and a skin irritant it’s ATF. If it’s not, it is most likely a different tree fern.
Other key differences include overall silhouette, and the trunk. The silhouette of ATF resembles a martini glass while Hāpu’u has more of an arched shape. The trunk of the ATF is skinny and has a ‘scaly’ texture from where the fronds fall off from and is hard when touched. Whereas Hāpu’u has a thick, soft fiber wrapping.
What can you do?
ATF is often sold and planted in gardens. To prevent further human spread don’t buy ATF when offered in stores or nurseries. Supply and demand dictates where and in what quantities ATF is sold. If the big box stores can’t sell it, they lose incentive to put it on the shelves again.
You can also write to your legislators! Follow this link (https://www.capitol.hawaii.gov/fyl/) and you can type your address or zoom in on the map, select the district on the map, and click the arrow on the right side of the blue box. The web page will redirect you to a page with your legislators’ contact information. Please note some districts have multiple legislators you can contact, so be sure to contact whomever you’d like or message all of them. You can also contact the Hawai’i Department of Agriculture at (https://hdoa.hawaii.gov/contact/) and relay your concerns.
To learn more about ATF, follow these resources:
https://www.ctahr.hawaii.edu/invweed/WeedsHI/W_Sphaeropteris_cooperi.pdf
