Highways Roadside Restoration with Native Ferns
Researchers at the University of Hawaiʻi Harold L. Lyon Arboretum recently wrapped up a five-year project funded by the Hawaiʻi DOT; investigating the use of native Hawaiian ferns in roadside plantings on the island of Oʻahu. The project involved several common native fern species, including palapalai (Microlepia strigosa), uluhe (Dicranopteris linearis), palaʻā (Odontosoria chinensis), and two species of native sword fern: kupukupu (Nephrolepis cordifolia) and ʻokupukupu (Nephrolepis exaltata subs. hawaiiensis).
Horticulture technologies such as tissue culture and hydromulching were tested as a means to vastly increase the production and distribution of these ferns.
This can be seen as uluhe creeps its rhizomes into fresh earth after a landslide in the steep
slopes of the Koʻolaus, or as kupukupu begins to germinate from spores that have landed Tissue cultu perfectly into re productio n the cracks of a lava field on the Big Island of Hawaiʻi.
This process starts the creation of a forest by building and stabilizing the soil, developing a habitat for more native species and securing the watershed. Ferns are a hopeful prospect in the restoration of urban areas utilizing these same strategies to colonize areas disturbed by construction.
These species were selected for their specific attributes such as erosion control, accessibility, propagation requirements, and beautification.
In the unique ecosystems of the Hawaiian Islands, the benefits of native ferns are numerous. As first succession species, native ferns are the first colonizers of a new terrain.
By: Casey Abe
Ferns were propagated at the Lyon Arboretum Hawaiʻi Rare Plant Program tissue culture laboratory and the Magoon Research Facility. Test sites were established at the Shidler College of Business and along the H-1 Westbound Waialae on-ramp. Exotic species within the sites were removed after which hydromulch and hydro-capping techniques were tested as large scale planting applications. The results of this research provide a road-map for the mass production of Hawaiʻi’s native fern species and insight into site restoration techniques, which will help the State reach its goal of 25% native plantings in urban areas by 2025.
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