Puriri

For the locality near Thames, New Zealand, see Puriri, New Zealand. For the Royal New Zealand Navy minesweeper, see HMNZS Puriri (T02).
Puriri
Scientific classification
Kingdom: Plantae
(unranked): Angiosperms
(unranked): Eudicots
(unranked): Asterids
Order: Lamiales
Family: Lamiaceae
Genus: Vitex
Species: V. lucens
Binomial name
Vitex lucens
Kirk

Puriri (Vitex lucens) is an evergreen tree endemic to New Zealand.

History

Puriri was first collected (by Europeans) at Tolaga Bay by Banks and Solander during Cook's first visit in 1769. (It should be noted it was a well known and understood plant by Maori who first discovered and settled New Zealand). The plant was excellently described by Solander in his manuscript "Primitae Florae Novae Zelandiae" under the name Ephielis pentaphylla, and a drawing of considerable artistic merit was also prepared(7). The next botanist to notice puriri, Allan Cunningham, did not do so until 1826 when he observed it on "the rocky shores of Bay of Islands, growing frequently within the range of salt water." Cunningham named it Vitex littoralis, correctly assigning it to the Vitex genus but overlooking that littoralis had been used for a Malayan species 4 years earlier. Kirk proposed V. lucens in 1897 after attention had been drawn to the fact that V. littoralis was taken(4,7).

The Maori name of this tree is 'pūriri' or sometimes 'kauere' (26). The common name in English is usually 'puriri', although 'New Zealand mahogany' and 'New Zealand teak' occur in older printed sources, especially in reference to the timber.

Description

The lush palmate leaves of a young puriri

The Puriri tree can grow up to 20 m tall, with a trunk commonly up to 1.5 m in diameter, frequently thicker, and a broad spreading crown(9). The thin bark is usually smooth and light brown in colour(1), but can also be very flaky. Puriri was actively and selectively logged in the past to provided timber for a wide range of end uses. Only the best trees were felled, leaving the gnarled puriri often found on farm paddocks. This has given the impression that puriri is incapable of growing straight, but early reports of puriri describe naturally clear boles of 15 to 30 feet (4.5 to 9 m)(5) and there are still a few trees like that left. A good example of a well-shaped tree is behind Ruapekapeka Pa in Northland.

The dark green glossy leaves of puriri are palmate (=palm of hand; hand like) with usually 5 leaflets, or sometimes three. The lowest two leaflets are smaller than the other three. The leaflets have domatia, little pockets where the mid vein and branching veins meet(1). Nobody is quite sure what domatia are for. The underside and veins are a lighter green. (22). Seedling leaves are much more delicate and a lighter green with serrations along the edge(4). Seedling puriri can be confused with seedling kohekohe, Dysoxylum spectabile, the most obvious difference is that puriri leaflets originate from one point, whereas kohekohe leaflets are spread along the stalk. The branches of puriri, especially the young ones, are square in cross-section.

A large puriri near Ruapekapeka, Northland

Puriri is one of the few native trees with large colourful flowers. Many plants in New Zealand have white or green flowers. The tubular flowers of the puriri look rather like snapdragon flowers(23) and can range from fluorescent pink to dark red, rose pink (most common) or sometimes even to a white flower with a yellow or pink blush. The bright colour, the tube shape, copious nectar production and the hairs at the base of the flower tube all point towards birds pollinating this flower (the hairs stop insects from stealing the nectar). On the New Zealand mainland there is often plenty of nectar in the flowers because there aren't enough birds to eat all the nectar produced by the tree.

The flower has 4 lobes (made of 2 petals), 4 long stamen (the male part of the flower) and the style grows to be as long as the stamen after the pollen has shed. It is interesting to see how the flowers open. The petals overlap each other in the bud form. The growing stamen push the petals open. When the flower is fully open the style starts growing and reaches its full length just after the anthers on the stamen have shed all the pollen. The flowers occur in loose clusters of up to 12 flowers per cluster.

Some flowers can be found on the puriri all year round, though it does flower most heavily over winter. Ripe fruit can also be found all year round, but is more common over the summer. Puriri is a very important tree for native birds in the top half of the North Island because it provides a constant year-round food supply. Flowers and fruit are carried at the tips of the branches.

Puriri flower

The fruit is a bright red (usually) to a pale yellow (rarely, and only on white flowered trees) "cherry". It can grow as big as a cherry, but it is unpleasantly astringent. Puriri fruit is not the most nutritious sort in the New Zealand bush (high in carbohydrates, not lipids, sugars or calcium), but it is always there. The seed inside is a very hard pear-shaped kernel (26) that can contain up to 4 embryo seedlings. The seedlings from one seed can germinate at the same time or be spread over a year(4). When broken, the fruit has a bright thin juice, and a faint grape smell.

Distribution

Puriri is endemic to New Zealand and can be found in the upper half of the North Island from North Cape to the Waikato and Upper Thames, and from thence in small numbers southwards to Mahia Peninsula (39°10′S) on the east coast and Cape Egmont (39°27′S) on the west (rare inland south of latitude 37). Its altitudinal range is from sea-level to 800 m (2500 ft) above sea-level. Puriri tends to be associated with fertile or volcanic soils, and early settlers often sought out and burned puriri rich areas to obtain good farmland(4, 6).

Uses

A young tree with fruit

Puriri is an invaluable food source for native wildlife, as it provides both fruit and nectar in seasons when few other species produce these, thus it is often used in restoration planting, e.g. the Elvie McGregor Reserve between Waipoua Forest and Katui Scenic Reserve in Northland and on Tiritiri Matangi Island in the Hauraki Gulf. It is hoped that restoration planting, with trees such as puriri, will provide a year round food source for birds, boosting their populations. For example, puriri is highly valued as an aid in increasing kereru (native pigeon) populations. Maintaining kereru populations is particularly important for natural restoration and maintenance of forest remnants, as this bird is the main disperser of large fruited species.

Puriri is also important as a host for a number of species. The puriri moth (or ghost moth) Aenetus virescens is New Zealands largest and quite spectacular moth, with a potential wing span up to 15 cm. Its 10 cm long larvae, though not restricted to puriri, often makes its home in the tree by excavating long "7"-shaped burrows . The moths are much reduced in number as the great swarms "invading rooms, sufficient in number to extinguish lighted lamps" reported by early settlers no longer occur(8). The wide spreading branches also provide room for epiphytic species such as Astelia, puka Griselinia lucida and northern rātā Metrosideros robusta(9).

Puriri in traditional Maori medicine has been used as a rheumatic remedy for centuries.

Historical Māori use

The Māori used infusions from boiled leaves to bathe sprains and backache, as a remedy for ulcers, especially under the ear, and for sore throats(10). The infusion was also used to wash the body of the deceased to help preserve it(6). Puriri trees or groves were often tapu through their use as burial sites(15) and puriri leaves were fashioned in to coronets or carried in the hand during a tangi (funeral)(6).

Puriri timber is usually greenish dark-brown, but sometimes nearly black or streaked with yellow, it was often used for implements and structures requiring strength and durability. The Maori preferred other timbers to puriri as its cross-grain made for difficult carving, but puriri garden tools and weapons had a long life and legend has it that buckshot used to ricochet off puriri palisades(11). It was used in the construction of hinaki (eel traps) because it was one of the few timbers that would sink(6). Puriri was sometimes used to dye flax fibres yellow(24), the sawdust can produce intense yellow stains on concrete floors.

The Puriri provides the strongest wood in New Zealand, allowing to make things such as bridges and paddles from it.

Historical European use

Puriri may bear flowers throughout the year

The European settlers used great quantities of puriri timber for fence posts, railway sleepers, shipbuilding and house blocks, as it is ground durable without treatment for 50 years or more (6, 12, 26). This, as well as the agricultural desirability of the soil in which it grew, led to the depletion of once widely spread lowland puriri forests(12), and by the mid-1940s the supply of puriri timber was almost exhausted(13). Puriri was also favoured for furniture and decorative wood work such as inlay veneers, as its appearance was "quite equal to the best Italian or American walnut"(14). Look at the New Zealand Geographic article on Seuffert & Son to see some good examples of puriri use in furniture. Puriri timber was sometimes called New Zealand teak(13), oak(5, 16) or walnut(14).

Current and potential future usage

Currently small quantities of puriri timber are available from time to time around the greater Auckland province and Northland(17), these tend to be mostly used for wood-turning or, as in the case of puriri fence posts, be recycled as garden furniture (6, 18). The erstwhile Forest Research Institute (now Scion) recommends planting fast-growing high quality timber species such as puriri as special purpose species, particularly in view of the rising cost of importing these and the scarcity of native timber(19).

A special-purpose species is defined as "a species producing timber with special wood properties required for those uses where radiata pine (Pinus radiata D. Don.) is not entirely satisfactory". Therefore, the timber will usually be complementary to that of Pinus radiata, not an alternative. Some of the special-purpose end uses advocated were; furniture, veneer, turnery, exterior joinery, boat building and tool handles(20). Puriri has fulfilled these roles in the past. Other potential roles for puriri include post, wharf and bridge pilings, as pine requires a high degree of preservative treatment and can break too readily under pressure due to lack of cross-grained wood(21). Indications are that puriri could coppice well, and, as it is one of New Zealand's hottest burning timbers(6), it might prove suitable as a source of biomass or for charcoal production.

See also

Wikimedia Commons has media related to Puriri.

References

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