Joanne Green, Rainer Hartlieb and Zia Flook
Introduction. The wildfires of November and December, 2019, burnt over 5,500 hectares of Nightcap National Park and the surrounding areas, including the rural communities of Huonbrook and Wanganui inland from Byron Bay in NSW, Australia. The fires occurred during a period of extreme fire risk after 2 years with below average rainfall. They mainly burnt the sclerophyll forest along the ridgetops, but the extreme conditions also saw fire burn the edge of the rainforest where it was eventually extinguished.
This summary reports on actions on one multiple occupancy property in Huonbrook, NSW after an ember attack from the Mt Nardi fire entered the property in the early hours of the 9th November 2019. During the fire, residents evacuated. Their homes were saved but they returned to find that the fire burnt an area of eucalypts – mainly Flooded Gum (Eucalyptus grandis) and several bamboo species that had been planted during the late 20th century to reforest an area where subtropical rainforest had been-long cleared for dairy farming. The plantings had also become infested with weed including Camphor Laurel (Cinnamomum camphora) and Lantana (Lantana camara), the latter increasing their combustibility under dry conditions. After the fires, the landholders sought solutions that could provide a more fire-resistant barrier to reduce potential fire threat to homes and the nearby remnant rainforest. As a result they opted to restore the buffer zone with the more fire-retardant subtropical rainforest that had been the original native vegetation of the area.
Works undertaken. Starting in March 2020, with support from Madhima Gulgan’s Indigenous bush regeneration team, Huonbrook residents and landowners commenced work on the site. The first task in any zone to be treated was to clear the debris sufficiently to allow access for weeding and planting. The second task was to identify any subtropical rainforest species (germinating after the fire) that were to be retained and to note areas that were bare and would be suited to plantings. (No planting was done where there was any natural regeneration.) The third task was to remove prolific exotic weeds, while protecting the natives, with the final task involving planting, staking and tree guarding.
The main weed species on site were Lantana, Running Bamboo (Phyllostachys spp.), Kahill Ginger (Hedychium gardnerianum), Winter Senna (Senna x pendula), and Inkweed (Phytolacca octandra). A total of 12 rainforest tree species germinating included the secondary species Red Cedar (Toona ciliaris) and Celerywood (Polyscias elegana) and the pioneers Red Ash (Alphitonia excelsa), Macaranga (Maccaranga tanarius) and Bleeding Heart (Homolanthus populifolius). A total of seven native rainforest understorey species resprouted including Dianella (Dianella caerulea), Native Ginger (Alpinia caerulea.) and Cordyline (Cordyline petiolaris).
Some 300 rainforest trees (around 30 species) and another 300 understorey plants have been planted at the site to date from May-Sept 2020, with a total of 3600 plants proposed to be planted on additional fire affected sites as part of this project. Locally occurring tree species planted to date include Lillipilly (Acmena smithii), Native Tamarind (Diploglottis australis), Firewheel Tree (Stenocarpus snuatus), and Long-leaved Tuckeroo (Cupaniopsis newmanii) Understorey species planted included Dianella, Lomandra, Native Ginger and Cordyline. All required tree guards to protect them from browsing by the native Red-necked Pademelon (Thyogale thetis).
After the planting, more natural regeneration of weed and natives occurred, particularly of the ground ferns; Harsh Ground Fern (Hypolepis muelleri), Binung Fern (Christella dentata), and Soft Treefern (Cyathea cooperi). Since the rain in autumn 2020 and the above average rainfall year that has followed, the landholders are managing weed in the regeneration and plantings together and work is now extending into the unburnt buffer zone.
Results to date: Nearly 12 months after planting has seen a nearly 100% survival rate and many of the planted trees have grown to an average height 1-2m. The number of native rainforest species on site now is approximately 25 tree and 23 understorey species and vines. Ferns cover 40% of the site. The difference between the number planted and the number on site (18 species) can be attributed to natural regeneration.
Further colonisation of rainforest species is expected over time. Whilst, in hindsight, we see that much of the site could have been captured by natives as a result of weed management alone, the planting has added a broader diversity of species, and will accelerate the process of succession to a more mature rainforest stand.
Acknowledgements: The Madhima Gulgan Indigenous bush regeneration team was funded by the inGrained Foundation and the Rainforest 4 Foundation. See https://www.rainforest4.org/. Technical advice was provided by Joanne Green.