Burning a win for restoration at Deep Creek Conservation Park
With so many factors at play to determine the appropriate timing of a prescribed burn, it’s a real win when it can be done at the perfect time to benefit a dominant plant species in the area.
Xanthorrhoea semiplana, commonly known as Yaccas or Grasstrees, is an iconic plant species in Deep Creek Conservation Park. They play an important role in the natural ecosystem, and burning the plants at the right time stimulates flowering and seeding.
In Autumn 2016 a 270 hectare prescribed burn was conducted in the south-western end of Deep Creek Conservation Park. The burn carried well through the thick vegetation, and was extinguished in the late afternoon as the predicted sea fog rolled in and dampened the conditions down.
This particular burn stimulated a mass flowering of the many Xanthorrhoea semiplana in the burn area, which is now providing benefits not just for this piece of land, but also for a large scale restoration project on degraded land within the Park.
Seed availability can be a challenge for such projects, as direct sowing of seed requires large quantities to be collected. Seed collectors are regulated by permits and are careful not to collect too much from and given area, being sure to leave plenty there for both the creatures that eat the seed, and hopefully, for the next generation of plants. The issue with Xanthorrhoea semiplana and the reason this burn was so beneficial is that usually there is not a large enough quantity of seed for large revegetation projects.
The inclusion of Xanthorrhoea semiplana seed in this restoration project will provide benefits for local fauna; these plants produce a valuable source of nectar for birds, as well as shelter for small mammals, birds and lizards. Yaccas are very slow growing plants, but they do germinate readily from seed.
Yaccas are not the only species that benefit from fire. Fire stimulates many native plants to flower and seed, release stored seed and germinate. Most South Australian ecosystems have evolved with fire over millions of years and for some species, fire plays an important part in their life cycles. Recently burnt areas are often a great source of seed for restoration projects, and fire continues to play an important role in regenerating plant communities for flora and fauna.
More about Xanthorrhoeas
Yaccas can live for a long time, and their “trunks” are actually accumulated leaf stems stacked on top of each other. It can take around 30 years before a significant trunk is achieved. They are also an important plant for Indigenous people, parts of the flower spikes were used in spear making, as a sweet nectar to make drinks from and as a resin to bind tools.