This month's kauri friend is kauri grass/kōkaha (Astelia trinervia). Despite its name, kauri grass is not actually a grass but is the tallest of NZ’s astelias, growing over two metres high with green flax-like leaves. Astelias are often confused with flaxes due to their leaf shape but are actually a perennial herb belonging to the lily family that is endemic to the Pacific and predominantly found in Aotearoa.
Kauri grass can be found growing both epiphytically, in the canopy of mature kauri, as well as on ground beneath the trees. Kauri grass is a common understory species throughout kauri forest. The flat, flax-like leaves create the perfect habitat for a range of insects and invertebrates. The large sprays of crimson berries are primarily dispersed by frugivory (fruit eating animals).
Kauri grass seeds are a traditional indigenous food whose seeds provide a good source of essential fatty acids. Kauri grass has various recorded uses including cosmetics and dyes from the crimson berries, hat making, thatching, candle wicks and paper products.
Kauri trees are considered ecosystem engineers due to their effect on soil composition; the highly acidic leaf litter creates a nutrient poor, acidic soil type called podsol. There are several plant species, such as kauri grass, that are specially adapted to this environment, and therefore are only found in kauri forest.
Less than one percent of historic kauri forest remains and it is under threat from dieback. Kauri dieback threatens not only the trees themselves, but the entire ecosystem of associated flora and fauna (such as kauri grass) that they support. You can help protect kauri grass by following kauri dieback protocols as well as participating in predator control.
Visit Ada Reserve here in Kaipātiki to see lots of kauri grass!
Etymology:
astelia – stemless
trinervia – three nerves
Photo credit: Jacqui Geux