Botanical Name: Dacrycarpus dacrydioides
Species: D. dacrydioides
Dacrydium excelsum D.Don in Lamb., Dacrydium ferrugineum Houttee ex Gord., Dacrydium thuioides Banks et Solander ex Carr., Nageia excelsa Kuntze, Podocarpus dacrydioides Richard, Podocarpus thujoides R.Br. In Bennett, Podocarpus excelsus (D.Don) Druce; Podocarpus excelsus (D. Don.) Druce
Common Name: Kahikatea
Other Names: Kaikatea, Kahika, katea, k?aka, koro?
Kahikatea grows on the lowland forest and wetlands throughout the North and South Islands in New Zealand. Formerly dominant on frequently flooded, and/or poorly drained alluvial soils. Occasionally extends into lower montane forest. Once the dominant tree of a distinct swamp forest type all but extinct in the North Island – the best examples remain on the West Coast of the South Island.
Kahikatea is a stout, dioecious, cohort-forming conifer tree, 50 (-65) m. tall. Trunk 1(-2) m diam., often fluted and buttressed. Bark grey to dark-grey, falling in thick, sinuous flakes. Wood white, odourless. Trunks bare for 3/4 of length, subadults with a distinctive columnar growth habit, branches arising from 1/3 to 1/2 of trunk length. Branchlets slender, drooping. Leaves of juveniles subdistichous, subpatent, narrow-linear, subfalcate, acuminate, decurrent, 3-7 x 0.5-1mm red, wine-red, dark-green to green.; of subadults less than or equal to 4 mm., dark green or red; those of adults 1-2 mm., imbricating, appressed, keel, subtrigonous, lanceolate-subulate to acuminate with broader base, brown-green or glaucous. Male cones terminal, oblong, 10 mm. Pollen pale yellow. Ovule, terminal, solitary glaucescent. Receptacle fleshy, oblong, compressed, warty, 2.5-6.5 mm., yellow to orange-red. Seed broadly obovate to circular (4-)4.5-6 mm diam., purple-black, thickly covered in glaucous bloom.
The species is dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required). and is pollinated by Wind. The plant is not self-fertile.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland). It prefers moist soil.
Requires sheltered moist woodland conditions. Plants are not very frost-tolerant and are only hardy outdoors in the mildest areas of Britain. In their native habitat trees can reach 45 metres in height, but they are slow growing in Britain and rarely exceed 6 metre.
Fruit – raw. A sweet taste, it is palatable but with a slightly oily taste. Also used as a masticatory (this last report probably refers to the use of the resin). A resin is obtained from the tree, it is used as a chewing gum.
The timber was initially not so highly regarded by European settlers as it was less attractive, strong, or resilient to rot than the other coniferous timbers available such as totara. However, since the wood does not impart an odour, and is clean and lightweight, Kahikatea was used to make boxes for the exporting of butter when the refrigerated export became feasible from Australia and New Zealand in the 1880s. The butter was exported in 56 lb slabs, and kahikatea became less common as the export industry grew. Indeed, tall mature pure kaihikatea forest, a once distinctive and widespread wetland type, is all but gone except for very small patches mostly on the West Coast. The first bridge in Hamilton across the Waikato River was built mainly of Kahikatea about 1880 but the bridge quickly became unsafe due to rot. The piles (not of Kahikatea) are still visible in the vegetation alongside the Traffic (Bridge St.) Bridge.
Kahikatea was used for boat building up until the 1970s because of its long straight lengths. When 12% dry it is slightly lighter in weight than Kauri and white in colour. Kahikatea was also used as late as the 1980s to carve out waka, traditional vessels for Maori, in which they competed in various watersports in Kaituna Wetlands.
For M?ori, the kahikatea had many uses. The fleshy aril or koroi was an important food resource, and was served at feasts in great amounts. The wood was also favoured for making bird spears. Soot obtained from burning the heartwood supplied a pigment for traditional tattooing (t? moko).
Kahikatea, along with other trees in privately owned forests, can only be harvested under a permit system and if sustainable harvesting techniques are used. There are still a few old-growth remnants of kahikatea left in the Waikato (for example, at Mangapu and Mokau).
However, most kahikatea stands in the Waikato lowlands are relatively young forest fragments, about 80–100 years old. These fragments have grown up around a few old trees left standing after most of the original forest was cleared for farming. Some stands still have their original seed trees around which the new forest grew. These massive trees, with trunks occasionally over 2 m across, are about 400–500 years old.
There are about 370 kahikatea fragments in the Waikato region. They are typically small, between 0.5 and 50 ha, with half of them less than 5 ha. Most of them grow on the river floodplains of the Waikato Basin, Hauraki Plains and Mokau River.
Because humans now control flood events and re-sow flood-damaged pasture, it is unlikely to see many new areas of kahikatea forest developing in the Waikato. Scientists estimate that more than 98 of percent of the pre-European kahikatea forest has been lost nationwide.