Pahautea, kaikawaka, mountain cedar.
This is one of those plants that has been recognized as a good, simple species ever since it was first described. There are no synonyms, subspecies or varieties.
Trees to 21 m tall and 100 cm dbh; young plants fastigate, maturing to a long, bare bole with a pyramidal to conical crown of heavy, almost horizontally spreading branches that form distinctively billowing masses. Bark papery, shed in narrow, thin strips. Branchlets of juveniles are somewhat flattened and up to 3 mm broad, the leaves of the two lateral rows closely set. Branchlets of mature plants are tetragonous, bearing four rows of closely set leaves. Juvenile facial leaves are about 1 mm long and the lateral leaves about 3 mm long; adult leaves are subequal, about 2 mm long, triangular, acute and appressed. There are separate male and female cones, which occur on the same tree. Pollen cones are about 7-11 mm long, borne singly at the tips of short branchlets. Seed cones are ovoid, about 7-8 mm long, and are composed of four woody scales, each bearing a curved dorsal mucro. Seeds 2 (one to each fertile scale). Wood is red, soft and straight-grained, but splitting easily (Allan 1961, Dallimore et al. 1967, Salmon 1996, Metcalf 2002).
"Mountain cedar is a handsome and very distinctive tree that can be recognised even from some distance" (Metcalf 2002). It resembles L. plumosa, from which it differs chiefly in its smaller size, smaller leaves and cones, and in the four-sided character of the ultimate branchlets. It is reduced to a bush at higher elevations, or in wet ground (Dallimore et al. 1967).
New Zealand: N and S Is, at 250 to 1,850 m elevation, in wet forests from latitude 36° 50' southwards. Type locality in the Nelson Mountains (1,830 m) (Allan 1961, Dallimore et al. 1967, Salmon 1996). Hardy to Zone 8 (cold hardiness limit between -12.1°C and -6.7°C) (Bannister and Neuner 2001).
A specimen 125 cm dbh and 20 m tall is recorded from South Westland, New Zealand (Burstall and Sale 1984).
The wood is "soft, brittle, durable, less generally useful than that of L. plumosa, but would be suitable for many kinds of carpentry" (Dallimore et al. 1967).
Salmon (1996) says that a fine, almost pure stand occurs in Hihitahi State Forest east of Waiouru Military Camp, southeast of Mount Ruapehu. As the photographs show, some fine examples can also be found on Mt. Taranaki and Mt. Ruapehu. The finest stand I have seen is along the track up Hauhungatahi, a subsidiary cone west of Mount Ruapehu. To reach this stand, drive 5.5 km south from the highway junction in National Park to the tiny hamlet of Erua and park near the railroad tracks. Follow the tracks about 250 m south to where a small, weathered sign says 'Track' and follow it. The track heads almost continuously uphill, starting in a flax thicket and then, in the forest, passing progressively through elevation zones dominated by rimu (Dacrydium cupressinum), matai (Prumnopitys taxifolia), Hall's totara (Podocarpus cunninghamii), kaikawaka (Libocedrus bidwillii), yellow pine (Halocarpus biformis), mountain toatoa (Phyllocladus alpinus), bog pine (Halocarpus bidwillii) and pygmy pine (Lepidothamnus laxifolius). The highest subalpine forest has a dense forest of mature Libocedrus bidwillii and Halocarpus biformis only 5-7 m tall, with juvenile plants in the understory. The ecology of the area has been described by Druitt et al. (1990).
Its scientific name commemorates its collector, James Bidwill.
Druitt, D.G., N.J. Enright, and J. Ogden. 1990. Altitudinal zonation in the mountain forests of Mt Hauhungatahi, North Island, New Zealand. Journal of Biogeography 17(2): 205-220. Abstract: The altitudinal ranges for woody species, in the zone from 750 m to tree-line (c. 1160 m), are described for the western slopes of Mt Hauhungatahi, New Zealand. Both methods of direct and indirect gradient analysis are used to describe the altitudinal sequence. The pattern of species abundances over the altitudinal sequence indicated major zones (ecotones) of species compositional change at tree-line and at c. 1050 m. This latter boundary marks the upper altitudinal limit for many important tree species of the lowland and montane forest zones (e.g. Dacrydium cupressinum), and the first appearance of species characteristic of the sub-alpine forest zone (e.g. Phyllocladus alpinus and Dacrydium biforme). Ordinations of stand density and basal area data using Detrended Correspondence Analysis (DCA) revealed a highly significant correlation between stand loadings on the first axis and altitude. Furthermore, a break in the altitudinal arrangement of sample stands is apparent at c. 1050 m, confirming the change from montane to sub-alpine forest suggested by the indirect gradient analysis results. Classification of stands and species using Two-way indicator Species Analysis (TWINSPAN) did not identify the same break in the altitudinal sequence until the second division. Reasons for this are discussed. The arrangement of communities and ecotones on Mt Hauhungatahi is compared with data for other mountains in New Zealand.
Xiong, L., Palmer, J.G. 2000. Libocedrus bidwillii tree-ring chronologies in New Zealand. Tree-Ring Bulletin 56:1-16. Available online at www.treeringsociety.org/TRBTRR/TRBvol56_1-16.pdf (accessed 2006.06.05). See also chronology data at http://www.ncdc.noaa.gov/paleo/metadata/noaa-tree-5365.html, accessed 2007.11.01.
Farjon (2005) provides a detailed account, with illustrations.
Haase, Peter. 1986. A study of a Libocedrus bidwillii population at Pegleg Flat, Arthur's Pass, New Zealand. New Zealand Journal of Ecology 9:153-156.
The New Zealand Plant Conservation Network, accessed 2010.11.22.
Last Modified 2012-11-23