August in the hills with Barbara Mitcalfe and Chris Horne
Libocedrus plumosa, kawaka; Libocedrus bidwillii, pāhautea
The name Libocedrus is derived from Greek: libernos, incense, and kedros, cedar, because the wood is scented. NZ's two libocedrus species are long-lived endemics. They are usually called NZ cedars, but professional botanists say we should call them NZ cypresses because they have the scale-like leaves of cypresses, not the needle-like leaves of cedars. They have very tall, unbranched, lower trunks, topped by conical-shaped crowns, like Xmas trees. As emergents, they are easily recognised from a distance by this shape, plus their distinctive grey-brown bark hanging off in long, narrow, vertical strips.
Libocedrus plumosa - 'plumosa' describes its ‘feathery’ leaf form.
North Island - sea level - 600 m elevation, from Te Paki to Kawhia in the west, and Gisborne in the east. Formerly it was a common forest type in western Waikato, but is believed to have been logged to near-extinction. South Island - as far south as Westhaven Inlet.
Libocedrus bidwillii. Mountain cedar was named after plant collector John Bidwill (1815–1853), believed to be the first European to climb Ngauruhoe. Its Māori name 'pāhautea' means 'grey-bearded', probably referring to the thick clusters of Hymenophyllum malingii, an unusual, silvery-grey, endemic, epiphytic, filmy fern which usually clothes its trunks. It is named after Christopher Maling, (1841–1916), a NZ surveyor.
250 – 1200 m elevation. North Island - Coromandel Peninsula to the Tararuas. South Island - throughout the west side, but only scattered on the east side. Stewart Island - absent.
Reproduction in Libocedrus
Libocedrus are monoecious: a kawaka tree bears both female and male cones, and so does pāhautea. Libocedrus are unique among NZ conifers, because they bear seed cones with woody bracts (modified leaves). Pollen produced by the male cones and carried on the wind, enters the tiny apertures (micropyles) of the female cones, and fertilises them.
The seeds of both species develop one large wing and one small wing. These make a seed spin like a helicopter rotor, facilitating its wind-driven dispersal beyond the drip-line of the parent tree. This makes it more likely that the resultant seedling will thrive because it will not have to compete with the parent tree, for nutrients.
The dark-red wood of both species has never been available in large quantities. Kawaka wood has been used for cabinet-making and roofing shingles. It is so resistant to burning, that it has sometimes been used to make fire-doors! Pāhautea wood, light, but very durable, has been used for boat decking, railway sleepers, roofing shingles and weather-boards.
Thanks to Jeremy Rolfe for the image, scanned from Dawson and Lucas NZ’s Native Trees, p. 78.