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32-636: Metrosideros excelsa , commonly known as the pōhutukawa , New Zealand Christmas tree , or iron tree , is a coastal evergreen tree in the myrtle family, Myrtaceae , that produces a brilliant display of red (or occasionally orange, yellow or white) flowers, each consisting of a mass of stamens . The pōhutukawa is one of twelve Metrosideros species endemic to New Zealand. Renowned for its vibrant colour and its ability to survive even perched on rocky, precarious cliffs, it has found an important place in New Zealand culture for its strength and beauty, and

64-469: A coastal shrub with white berries, Sophora tomentosa . The -hutu- part of the word comes from * futu , the Polynesian name for the fish-poison tree ( Barringtonia asiatica ; compare with Fijian : vutu and Tongan : futu ), which has flowers similar to those of the pōhutukawa. Pōhutukawa grow up to 25 metres (82 ft) high, with a spreading, dome-like form. They usually grow as

96-497: A cold or dry/wet season. Evergreen trees also lose leaves, but each tree loses its leaves gradually and not all at once. Most tropical rainforest plants are considered to be evergreens, replacing their leaves gradually throughout the year as the leaves age and fall, whereas species growing in seasonally arid climates may be either evergreen or deciduous. Most warm temperate climate plants are also evergreen. In cool temperate climates, fewer plants are evergreen. In such climates, there

128-659: A height of 20 metres and a spread of 38 metres (125 ft). A pōhutukawa tree with an estimated age of 180 years known as 'Te Hā' is fully established at an Auckland City park. 'Te Hā' is the largest urban specimen in the country. Plans to build a monument in honour of victims of the Erebus Disaster in proximity to the tree activated significant local opposition in 2021. Evergreen There are many different kinds of evergreen plants, including trees , shrubs , and vines. Evergreens include: The Latin binomial term sempervirens , meaning "always green", refers to

160-731: A higher soil acidity and lower soil nitrogen content. This is the case with Mediterranean evergreen seedlings, which have unique C and N storages that allow stored resources to determine fast growth within the species, limiting competition and bolstering survival. These conditions favor the growth of more evergreens and make it more difficult for deciduous plants to persist. In addition, the shelter provided by existing evergreen plants can make it easier for younger evergreen plants to survive cold and/or drought. Evergreen plants can have decorative as well as functional uses. In months where most other plants are dormant, evergreens with their sturdy structure, and vibrant foliage are popular choices to beautify

192-711: A kneewall-like space. A ship's knee has two parts called the arm (shorter) and a body (longer). The outside surfaces come to a corner, (typically 90 degrees in buildings) called the heel. The inside surface retains its natural shape and the curve is called the bosom. The thickness between the heel and bosom is the throat. The ends of the arm and body are the toes. The names of ship's knees are based on their position: Knees can be blind pegged with foxtail wedges on both ends or bolted in place. Due to tradition, ease of workability, strength and durability characteristics, some species of wood are particularly prized for making knees. Tamarack (also known as hackmatack ) stumps are among

224-423: A landscape. Additionally, evergreens can serve as a windbreak , stopping heat loss from buildings during cold months when placed on the northwest side of a structure. Knee (construction) In woodworking , a knee is a natural or cut curved piece of wood. Knees, sometimes called ship's knees, are a common form of bracing in boat building and occasionally in timber framing . A knee rafter in carpentry

256-420: A larger volume of parenchyma and air spaces per unit leaf area. They have larger leaf biomass per unit leaf area, and hence a lower specific leaf area . Construction costs do not differ between the groups. Evergreens have generally a larger fraction of total plant biomass present as leaves (LMF), but they often have a lower rate of photosynthesis. Deciduous trees shed their leaves usually as an adaptation to

288-403: A marketable shape ( coppicing and pollarding were used for small, straight timbers, like withies ). A sharp bend in a piece of wood is also called "cranked". Commonly used in shipbuilding known as ship's knee for their advantage of reducing the encroachment into the usable space of the structure since there is no spandrel . Also knee rafter increases the usable space in an attic by creating

320-431: A multi-trunked spreading tree. Their trunks and branches are sometimes festooned with matted, fibrous aerial roots . The oblong, leathery leaves are covered in dense white hairs underneath. The tree flowers from November to January with a peak in early summer (mid to late December), with brilliant crimson flowers covering the tree, hence the nickname New Zealand Christmas tree. There is variation between individual trees in

352-433: Is a bent rafter used to gain head room in an attic. Wood is a highly anisotropic material (its strength varies considerably with the direction of applied force, i.e., parallel, radial, or tangential to the grain). Because wood is strongest when loaded in tension or compression along the grain, the best knees are those in which the wood grain follows the bend. For a knee with relatively little bend, it may be possible to cut

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384-438: Is a predominance of conifers because few evergreen broadleaf plants can tolerate severe cold below about −26 °C (−15 °F). In addition, evergreen foliage experiences significant leaf damage in these cold, dry climates. Root systems are the most vulnerable aspect of many plants. Even though roots are insulated by soil, which tends to be warmer than average air temperatures, soil temperatures that drop too low can kill

416-417: Is made from a natural crook or bend in a tree. Grown knees can be taken from several locations within a tree. The roots are a particularly useful source as the root structure of many species of trees naturally spreads out laterally just beneath the ground in order to help anchor the tree. This provides a fairly reliable source of approximately 90 degree crooks which may be impossible to find in other portions of

448-550: Is regarded as a chiefly tree ( rākau rangatira ) by Māori . The generic name Metrosideros derives from the Ancient Greek mētra or " heartwood " and sideron or "iron". The species name excelsa is from Latin excelsus , "highest, sublime". Pōhutukawa is a Māori word . Its closest equivalent in other Polynesian languages is the Cook Island Māori word po'utukava , referring to

480-501: Is renowned as a cliff-dweller, able to maintain a hold in precarious, near-vertical situations. Like its Hawaiian relative the ʻōhiʻa lehua ( M. polymorpha ), the pōhutukawa has been shown to be efficient in the colonisation of lava plains – notably on Rangitoto , a volcanic island in the Hauraki Gulf. In New Zealand, pōhutukawa are under threat from browsing by the introduced common brushtail possum which strips

512-446: Is unsuitable. To avoid this issue knees requiring sharper curves are made using methods which ensure that the wood grain and direction of load are closely aligned. This can be achieved by steam bending , laminating , or selecting a natural crook with matching grain - a "grown knee". Grown knees are generally considered as the best method among boat builders and have a strong traditions associated with their use, but they may not achieve

544-594: The North Island of New Zealand, north of a line stretching from New Plymouth (39° S) to Gisborne (38° S), where it once formed a continuous coastal fringe. By the 1990s, pastoral farming and introduced pests had reduced pōhutukawa forests by over 90%. It also occurs naturally on the shores of lakes in the Rotorua area and in Abel Tasman National Park at the top of South Island. The tree

576-796: The Wellington area and in the north of the South Island . It has also naturalised on Norfolk Island to the north. Pōhutukawa have been introduced to other countries with mild-to-warm climates, including south-eastern Australia, where it is naturalising on coastal cliffs near Sydney . In coastal California , it is a popular street and lawn tree, but has caused concern in San Francisco where its root systems are blamed for destroying sewer lines and sidewalks. In parts of South Africa , pōhutukawa grow so well that they are regarded as an invasive species . The Spanish city of A Coruña has adopted

608-476: The area in which they reside. The excellent water economy within the evergreen species is due to high abundance when compared to deciduous species. Whereas deciduous trees lose nutrients whenever they lose their leaves. In warmer areas, species such as some pines and cypresses grow on poor soils and disturbed ground. In Rhododendron , a genus with many broadleaf evergreens, several species grow in mature forests but are usually found on highly acidic soil where

640-404: The desired bend into the layup and securing it until the adhesive sets. Laminated knees are very strong and can be made in shapes which would be difficult to achieve using other methods, but they require time for the adhesive to cure, they are messier to construct, and they must use a jig or fixture to secure them until the adhesive cures. Grown - The term "grown knees" refers to any knee which

672-552: The evergreen nature of the plant, for instance: The longevity of individual leaves in evergreen plants varies from a few months to several decades (over 30 years in the Great Basin bristlecone pine ). Japanese umbrella pine is unique in that it has its own family of which it is the only species. Evergreen and deciduous species vary in a range of morphological and physiological characters. Generally, broad-leaved evergreen species have thicker leaves than deciduous species, with

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704-433: The knee out of a single straight-grained board and still achieve sufficient strength. However, with increasing bend this method becomes problematic since more and more of the knee is aligned across the grain and is therefore considerably weaker. A knee laid out this way might easily snap in two under hand pressure alone, even if it is generously sized. In boat joinery constantly subject to shock and fatigue loading this method

736-423: The nutrients are less available to plants. In taiga or boreal forests , it is too cold for the organic matter in the soil to decay rapidly, so the nutrients in the soil are less easily available to plants, thus favoring evergreens. In temperate climates, evergreens can reinforce their own survival; evergreen leaf and needle litter has a higher carbon-nitrogen ratio than deciduous leaf litter , contributing to

768-448: The plant. The exact temperature which evergreen roots can handle depends on the species, for example, Picea Glauca (White Spruce) roots are killed at −10 °F (−23 °C). In areas where there is a reason for being deciduous, e.g. a cold season or dry season, evergreen plants are usually an adaptation of low nutrient levels. Additionally, they usually have hard leaves and have an excellent water economy due to scarce resources in

800-475: The pōhutukawa as a floral emblem. At least 39 cultivars of pōhutukawa have been released. Duncan & Davies nurseries were a leading force in the mid-20th century, while the late Graeme Platt has been responsible for 16 different cultivars so far, including a rare white-flowering tree. Cultivars include: A giant pōhutukawa at Te Araroa on the East Coast is reputed to be the largest in the country, with

832-410: The roots grow they envelop small particles of soil and rock, which acts as an embedded abrasive and accelerates the wear of edged tools. For species of wood with appropriate splitting characteristics, such as oak, the stump can be split into wedges, with one large root on each wedge; each wedge is then carved into a rib for a small boat. Historically, tree shaping was sometimes used to grow a tree into

864-437: The same strength as a good laminated knee. Bent - Bent knees are formed by plasticizing the wood to make it flexible via boiling, steaming, or microwaving (for small components). While still hot, the wood can be bent into a shape suitable for the location - either on a form or by forcing and securing it directly into the final service location. Steam-bending is a time-honored method for shaping boat frames, but it does weaken

896-513: The timing of flowering, and in the shade and brightness of the flowers. In isolated populations genetic drift has resulted in local variation: many of the trees growing around the Rotorua lakes produce pink-shaded flowers, and the yellow-flowered cultivar 'Aurea' descends from a pair discovered in 1940 on Mōtītī Island in the Bay of Plenty . The pōhutukawa's natural range is the coastal regions of

928-435: The tree of its leaves. A charitable conservation trust, Project Crimson , has the aim of reversing the decline of the pōhutukawa and other Metrosideros species – its mission statement is "to enable pōhutukawa and rata to flourish again in their natural habitat as icons in the hearts and minds of all New Zealanders". Pōhutukawa wood is dense, strong and highly figured. Māori used it for beaters and other small, heavy items. It

960-435: The tree. In order to obtain this raw material for knees builders may dig up a stump in its entirety, as unlike other portions of the tree, it is impossible to judge the quality and quantity of available material in the roots as they are underground. Once the stump has been dug up the knees can be sawn or split from suitable natural crooks. However, knees sawn from a stump can quickly dull tools used to shape and finish them - as

992-402: The wood slightly, it can leave residual stresses which may cause breakage or spring-back over time, and it is limited in the degree of bend which it can achieve, particularly for thick members. Also, not all species of wood steam bend well. Laminated - Laminated knees are formed by coating thin, flexible strips of wood with adhesive, layering them to achieve the required thickness, then forcing

Metrosideros excelsa - Misplaced Pages Continue

1024-417: Was frequently used in shipbuilding, since the naturally curvy shapes made strong knees . Extracts are used in traditional Māori healing for the treatment of diarrhoea, dysentery, sore throat and wounds. Pōhutukawa are popular in cultivation, and there are fine examples in most North Island coastal cities. Vigorous and easy to grow, the tree flourishes well south of its natural range, and has naturalised in

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