Abstract:
Mamaku (Cyathea medullaris) is native New Zealand tree fern species common to lowland habitats. Ecologically it tends to occur on high-light, moist, frost-free sites of moderate fertility. Mamaku is the most shade-intolerant of New Zealand tree ferns, and therefore often occurs early in succession after a disturbance (a pioneer species), on forest edges or within tree-fall gaps. It is also the largest and fastest growing of New Zealand tree ferns, with height growth ranging from 11–50 cm per year. Growth rates are highest when trunks are short-statured and reduce as plants attain greater height. Mamaku can be grown from fresh spores, transplanted as young plants, or freshly felled trunks will usually resprout if planted and carefully watered. Germination from spores, however, can be slow, and the rate of failure of transplanted sporelings can be high. Mamaku are not susceptible to many pests and diseases, however possums will browse newly emerging mamaku frond bases during spring. Mamaku occurs within the clade Sphaeropteris within the Cyatheaceae, and there are eight close relatives of this species. Future research should focus on determining variation in mamaku growth rates under different environmental conditions and effective propagation techniques relative to site scale and context.
