July 29, 2008

NZ Timbers for Woodcrafting

New Zealand farms have nearly all been cleared from native bush in our 150-year farming history, so there is always left-over timber around, either in old tree stumps, old fence posts, or timber buried in the ground. These timbers are a wonderful resource for woodworking crafts, especially woodturning and wood carving. These wood details are useful summaries to go with the article made, so the owner has some appreciation of the tree and it’s wonderful timber.
Kahikatea

Kahikatea (Dacrycarpus dacrydioides) is the New Zealand “white pine” and is the tallest tree in our native bush. It is a member of the Podocarpacae family characterised by their smooth bark which prevents creepers attaching and eventually smothering the tree.

The juvenile seedling leaves are longer than the drooping twigs with fine needle leaves. The mature adult leaves are larger again and more sparse.

The tree grows to 50m high and 1.5m in diameter with grey tapering trunk free of branches for the first 25m. Kahikatea are found throughout lowland forest areas and is most obvious in dense stands of trees in swampy areas. It is regularly seen in developed farm land where clumps of trees have been left for shade. These trees need to be fenced as the tree roots are damaged by stock.

Kahikatea timber is white with a pale yellow heart and is very straight grained. It was used extensively by the early pioneers for household utensils, especially milk churns, bowls and ladles. It was also the main timber used for boxes to export cheese, butter and apples as it didn’t taint the produce during long ship voyages.

Kahikatea is not a popular turning wood and the heart wood is preferred as it has a bit more character. The sapwood is very susceptible to attack by the common borer (Anobium punctatum).

Kowhai

The drooping bell-like bright yellow flowers of the Kowhai are New Zealand’s national flower. There are three species, all members of the Papilionaceae family. Sophora tetraptera is the common large tree that grows widely along forest margins, on river banks and lake edges, or in damp rocky places. Trees can reach 12m tall.

Leaves are pinnate with many 10-12 pairs of oval leaflets. The long seed pods with each seed in a separate compartment are very characteristic. Seeds are toxic. The bark was used by Maori for medicinal purposes in poultices and infused with Manuka bark for internal pains.

Kowhai timber has a dark brown patterned heart wood with lighter brown to yellow sap wood wit a nice grain. The timber is very hard, dense and durable and turns and finishes well. The timber was never used commercially and the dust from sanding is considered to be toxic.

Maire

There are four species of Maire. The most common ones in New Zealand are White Maire (Gymnelaea lanceolata) and Black Maire (Gymnelaea cunninghamii). Both are in the Oleaceae family. White Maire wood is yellow to light brown in colour and black Maire is darker brown with very dark to black stripes through it.

Trees in the bush are canopy trees that grow up to 20m high and can be 1.5m in diameter. They have rough oak-like bark, with lanceolate leaves that are 100mm long and 12 mm wide, dark green on the upper surface and lighter green below.

The timbers of both species are extremely hard and dense which posed great milling and handling problems for the early pioneers. Maire was used as posts for fencing and stockyards but it had to be worked when it was green. They lasted forever, but it was almost impossible to drive staples into them.

Maire was a very popular firewood as it gave out great heat but rapidly burned out the grate. The problem was to split it, which was best done when it was green or where there were cracks in it.

The timber today is almost rare. It has a very characteristic smell when turning and finishes well with a natural high polish. The dust is not considered as being toxic. It has been popular for woodwind musical instruments and has now been rediscovered for golf clubs.


Matai

Matai (Prumnopitys taxifolia) is a robust forest tree that grows up to 25m high with a trunk diameter of up to 1.3m. It is found throughout New Zealand and was called “black pine” by early European settlers. As a member of the Podocarpaceae family it has a smooth deciduous bark that prevents creepers attaching themselves and eventually smothering the tree.

The leaves are dark green above and light green below with a dark midrib. It’s a bit like yew. The fruit is a black cherry-like berry.

The timber can be variable in colour but is generally a lovely golden brown when polished. It has straight grain and is harder and heavier than other New Zealand Podocarps, but it is easy to work. It has a pleasant smell when turning and the dust is non toxic.

Matai was used extensively for floor boards in houses and village halls where it stood the test of time and stiletto heels! It was easy to maintain and refurbish with a good polish.

Miro

Miro (Prumnopitys ferruginea) in the Podocarpaceae family is one of New Zealand’s noted rain forest trees, reaching 25m high and 1.5 to 2m in diameter. It has dark green foliage like English Yew, with purplish plum-like fruit. Miro has smooth bark common to other Podocarps, designed to stop creepers attaching and smothering the tree.

Miro was used like Rimu for housing and furniture but it didn’t seem to have quite the same status. It was sometimes called “poor man’s Rimu”. Miro is a hard dense timber, a more brownish colour than Rimu and was called “brown pine” by the early pioneers.

It is an excellent wood for turning, finishing well and not having such an irritating and toxic dust as Rimu.

New Zealand Kauri

The New Zealand Kauri (Agathis australis) is a member of the Araucariaceae family and is one of the world’s largest trees. It is unique to New Zealand where it grows in the semi-tropical northern part of the North Island down to a line from Te Aroha to Kawhia. Trees are massive growing to more than 30 m high and 5-7 m in diameter when mature, taking up to about 2000 years.

The needle leaves are thick, shiny, lanceolate 25mm x 8mm in size, with globular cones of 75m diameter. Tree trunks are very straight and cylindrical free of side branches as these are ejected naturally leaving no scar and perfect knot-free timber. The branches which are also massive develop at the very top of the tree. The bark is deciduous coming off in flakes, which prevent creepers attaching themselves and choking the tree.

The Kauri like the unique Podocarps that make up New Zealand bush, does not have a deep tap root. Kauri roots feed the tree from a network of surface roots absorbing nutrients generated in the deep layer of leaf litter. The largest remaining protected specimens of Kauri now have to be protected around their base from damage by visitors’ feet.

The Kauri has always been revered by Maori and is part of New Zealand’s early European history as Captain James Cook valued the timber to replace broken masts and spars in his explorations of the South Pacific.

Kauri’s unique golden yellow timber with beautiful straight grain was valued by early European pioneers who with their saws, axes and bullock teams could cut and process the massive trees. They used it extensively for houses, boats, bridges, furniture, fencing and household utensils. The timber was soon exported to build houses in early Sydney and San Francisco and the natural gum exuded by the tree was valued for shellac and the varnish trade.

Sadly, large areas of Kauri forest were burned by early settlers clearing land for farming, and it is now very difficult to obtain supplies of prime kauri timber.

A Kauri replanting programme is now underway and trees will be processed after 60-80 years for veneers. In the right conditions, kauri grow quickly and this offers great hope for the future. In the Waitawheta valley behind Mount Te Aroha where mature Kauri were harvested in the early 20th Century, it is now difficult to walk between the young growing trees.

Countless Kauri were blown down and buried in the many massive volcanic eruptions that took place in the North Island from 2000 to 40,000 years ago. The resinous quality of the wood and the swamp environment preserved the timber which is now being retrieved for furniture and turning. It has a very distinctive colour varying from light brown to green, depending on the swamp, silt or minerals which has covered it for all this time.

New Zealand Swamp Kauri

The New Zealand Kauri (Agathis australis) in the Araucariaceae family is one of the world’s largest trees. It is unique to New Zealand where it grows in the semi-tropical northern part of the North Island. Trees are massive and grow to more than 30 m high and 5-7 m in diameter when mature, which takes up to about 2000 years and have always been revered by Maori.

European settlers used Kauri for houses, boats, bridges, and furniture, fencing and household utensils. But sadly large areas of Kauri forest were burned to clear land for farming.

Countless Kauri were blown down and buried in the many massive volcanic eruptions that took place in the North Island thousands of years ago. The land developed into swamps so preserved the timber which is now being retrieved for furniture and turning. Swamp Kauri has a very distinctive colour varying from light brown to green, depending on the swamp or silt which has covered it. Waikato swamp kauri has been carbon dated as about 2,500 years old, and the Northland Kauri at over 40,000 years old.

Pohutukawa

The Pohutukawa (Metrosideros excelsa) is New Zealand’s “Christmas tree” as it produces rich crimson flowers in great abundance in mid December each year. It is a large spreading tree that grows up to 25m high and has many trunks spreading out from the tree at ground level. It is a member of the Myrtaceae family and is found in the northern parts of the North Island.

The leaves are simple lanceolates 25mm long x 8mm wide, dark green on the top and lighter green on the underside. The seeds of Pohutukawa are tiny and they spread long distances on the wind. As a result they are great colonising trees and are the first things to take root on volcanic areas. An excellent example of this is Rangitoto island in the Hauraki Gulf near Auckland.

Pohutukawa are very common around the coasts on high cliffs and down at high tide level where their twisted shape and shaggy aerial roots are very characteristic. Despite its hardness, marine borer soon damage it if emersed in seawater.

The timber is extremely hard and dense, and was treasured by early Maori for weapons and the keels of boats. It was never used commercially but is a beautiful timber to turn. The dust is not considered to be toxic. Mature heart wood is very dark red in colour, and younger trees produce more pinkish timber.

Puriri

Puriri (Vitex lucens) is a beautiful spreading tree of New Zealand’s native bush and is found in coastal and lowland forests in the Northern half of the North Island. It’s a member of the Verbenaceae family so is related to teak. It can grow up to 20m high with a trunk of 1.5m encased in thick bark.

The leaves of Pururi are compound with 3-5 leaflets which are corrugated and shiny. Flowers are pink or red and it has cherry-sized berries that turn from green to red when ripe. These berries are loved by native birds, especially the native pigeon.

The timber can vary from dark green to black and is extremely hard to work. But its hardness does not stop the ravages of the large Puriri moth or its larvae that bore holes about 15mm in diameter in the wood.

The Puriri moth does not restrict its ravages to the Puriri tree. It will attack other native trees and some introduced ones. Its tunnel goes is in the form of a figure seven. The top goes in 30-40mm and the vertical leg of the seven is about 200mm long. So seeing the entry hole you can predict where the damaged timber will be.

The wood was commonly used by early settlers for post and rail fencing as they lasted for ever. The timber was worked when green as it is almost impossible to knock staples into it when dry. Special shorter legged staples were used.

It is now a treasured timber for turning because it is in very short supply.

Rata

There are two kinds of Rata – the Northern Rata (Metrosideros robusta) found in the North Island of New Zealand and the northern half of the South Island. The Southern Rata (Metrosideros umbellata) is found mainly in the South Island. They both belong to the Mytaceae family. The leaves are small, lanceolate 25mm long x 8mm wide, and they often turn red when they die.

The Northern Rata is a lofty forest tree growing to a height of 30m. The Southern Rata is a smaller gnarled tree growing up to 20m high.

Rata trees sometimes start life as a seedling in the branches of other forest trees, usually carried there by birds. It then grows and puts down roots to the ground. These roots grow and eventually the Rata becomes the tree, with the original tree remaining a decaying hollow in the middle

But more often it grows as a vine which climbs the tree from the ground up the supporting host which is then often strangled so that the remains of the heartwood may often be found within the hollow base of mature M. Robusta trees.

Both Ratas have brilliant deep red flowers rather like the Pohutukawa.

The wood is a dull reddish brown in colour, is very straight grained and is exceptionally hard and dense. It was a renowned fire wood if you could split it with an axe. The secret was to chop it up when it was green. It is hard to season for turning without cracks appearing. The wood and dust is non-toxic.

The wood of the Northern Rata is not as heavy or dense as that from the Southern Rata.

Tawa

Tawa (Beilschmiedia tawa) is a tall lowland forest tree growing up to 25m high. It has a straight trunk of 1.25m diameter covered in almost black bark. But the blackness is caused by algae as the bark is naturally grey and smooth, rather reminiscent of English beech (Fagus silvaticus).

Tawa belongs to the Lauraceae (the laurel family) and forms pure stands in some areas.

The green leaves are simple, lanceolate, 50mm long x 10mm wide and are very thin and lacy. It has large 10mm diameter plum-like black berries loved by native birds.

Tawa grows throughout the North Island and in the northern parts of the South Island. Tawa timber has been widely used for building, especially flooring. It has also been used for furniture and internal fittings and panelling. It has also been, and still is a popular firewood.

The wood is a pale buff colour with a nice grain. The heart wood and knots are an attractive dark brown with some black streaks. It is very easy to work and is not classed as a toxic timber.

Titoki

Titoki (Alectryon excelsus) is a spreading tree growing up to 10m high throughout the North Island of New Zealand, and down to Banks Peninsula in the South Island. It grows from sea level up to 600m.

It belongs to the large, mainly tropical Sapindaceae family and has a short stout trunk which is often fluted, with smooth dark green bark, dull green lanceolate leaves and red berries containing a black seed.

Early European settlers called it the “New Zealand ash” as the leaves are like the European ash. But that’s where the similarity ends.

The timber which is strong, dense, elastic and is easily worked. It was used widely for bullock yokes, tool handles, wagon wheels, coach building and furniture. It was not durable in the open air.

Totara

Totara (Podocarpus totara) is one of New Zealand’s largest forest trees reaching 30m high and 2m in diameter and is found in lowland forest throughout the country.

As a member of the Podocarpaceae family it has a smooth deciduous bark that discourages climbers from attaching and smothering the tree. Totara has needle-like leaves 6mm long and 3mm wide and are flat and pointed.

The timber is a beautiful dark red and very straight grained. It is soft, easy to work and has a natural preservative in it so has a very long life when used for outside structures. Because of this natural preservativ, it must be primed properly before painting and sealed before applying any woodturning finishes.

Totara was recognised by early Maori settlers as valuable for carving and canoe building because it was easy to work and was very light and durable in water.

The early European settlers similarly recognised its qualities for housing, fence posts and battens. Large trees once felled could be easily cleaved with limited use of axes and wedges. Their lightness was also appreciated by pioneer farmers when packing Totara posts out to fence hill country blocks.

Totara has also been an important firewood as its straight grain makes it easy to split for kindling wood, and the natural oils assist in burning.

Most Totara used today for turning is recycled old fence posts that are now in short supply as millions have been burned when old fences were taken down and replaced with treated pine. Totara posts are now in great demand by landscape designers.

Rarely does an old mature tree come available for turning, and young trees do not have the wonderful dark red grain of older specimens. The natural gum in the wood clogs up sandpaper but the dust from sanding is not considered toxic.

No comments:

Post a Comment