Native Forest Restoration

The Hawaiian Section at Lyon Arboretum

The Hawaiian Islands are one of the most isolated archipelagos in the world. This isolation along with other abiotic factors including geological substrate and topography variation, extreme climatic contrasts over short distances creating a unique and a wide range of habitats have all contributed to a very special and unique flora. With less than 300 original colonists, the native flowering plants have radiated to over 1,100 species with one of the highest endemism rates in the world at nearly 90%! The biodiversity in our fern and fern allies is also amazing with nearly 188 native taxa including 143 endemic and 43 indigenous species. Nearly 76% of our native fern taxa are endemic! The other side of the story is that the Hawaiian Islands, like many other Oceanic islands are especially vulnerable to invasive species. This factor along with habitat alteration and human disturbances has led Hawaii to become better known as the extinction capital of the world with over 317 species listed as threatened or endangered!

The Hawaiian Section of the Lyon Arboretum is doing its small part in showcasing, educating and conserving some of the wonderful plant diversity found in the Hawaiian Islands. Not to be confused with our Native Hawaiian Plant Garden near the Visitor's Center, the Hawaiian Section began when staff members, Bob Hirano and Ken Nagata, started to remove some of the large Falcataria species from this ridge section. According to our database, in or around 1968, some of the first plantings of native species took place including some Pittosporum, Metrosideros, and Tetraplasandra species. Ken Nagata and Grounds and Collections Manager, Raymond Baker planted a nice groove of loulu (Pritchardia species) in the upper limits of the Hawaiian section near the majestic Royal Palm grove in the 1970's. Over the years many employees, student workers and volunteers have helped to plant and maintain the Hawaiian Section and within the past 10-15 years, there had been a push to extend the Hawaiian section and merge it with the Pritchardia grove in the upper limits of H34.

Since becoming collections curator of the Hawaiian section in 2006, Lïloa Dunn, has implemented a new strategy for the Hawaiian section (H34) which will increase the diversity of native plants in the Hawaiian section and further the idea of doing community-type restoration in the upper Hawaiian section. There has been some artificial delineation of the Hawaiian section by the author and it follows as such:

Lower Hawaiian Section

This part of the Hawaiian section starts from the Jeep trail and meanders up the ridge line through the Agathis grove with the older native plantings to the right. The upper limit of the Lower Hawaiian Section will be at the 2nd contour trail above the slope of Sapindus in the area that contains a grove of native Hibiscus species, some Pittosporum species and two keahi (Nesoluma polynesicum) plantings to the right. The Lower Hawaiian section, as was described earlier, represents the initial attempts to create a native Hawaiian plant section. Native taxa from across the Hawaiian Islands are planted here as part of our conservation collection and will continue sto be planted in the area.

Upper Hawaiian Section

The Upper Hawaiian Section begins at the end of the upper limit for the Lower Hawaiian section and continues up the ridgeline to the earlier planted Pritchardia grove. It also contains the shallow valley to the left of the main trail starting just above the Agathis grove. There are a series of contour trails (6 in total) that cross through the Upper Hawaiian Section and will be used as an artificial delineations of that section. The main focus of this Upper Hawaiian Section is to do ecological restoration at the community level. Instead of preserving individual species, our hopes are to preserve elements of native plant communities. Initial steps are underway by planting common native species in large numbers in hopes that these species will adapt to the site and reproduce. As these "commons" become established, some of the more rare species will be out-planted re-creating a familiar native plant community. Two major communities represented in the Hawaiian section will include: a Koa (Acacia) Mesic Forest and a `Ōhi`a (Metrosideros) Lowland Wet Forest (Wagner et. al, 1999). Other communities will be represented on a smaller scale include a Hala Forest (Coastal Mesic Forest) and a Pāpala Kēpau/ Pāpala (Pisonia/ Charpentiera) Riparian Forest (Wagner et. al, 1999). Within each of these community-types, there are associated native species that one would typically find in intact natural areas.

We have created a list of these species for targeted out-planting for each community-type.