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Plantation forestry has
developed rapidly in New Zealand. In 50 years, the country's
industrial wood supply has changed almost completely from
natural forests to managed forest plantations, thus emphasising
New Zealand Pine as the primary species.
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Extensive research and
experience in plantation forestry has provided a good
understanding of how New Zealand pine log quality can be
influenced by genetic selection, silviculture and the method of
conversion.
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New Zealand pine has
unique properties among softwood species, in that total
treatment of sapwood is always achievable. It is very amenable
to manipulation of preservative treatment processes, which are
environmentally acceptable and give a reliable standard of
treatment.
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New Zealand pine sawn
lumber is a versatile structural building material which is well
suited to the 2 x 4 building system. It is used equally
successfully in larger buildings as glue-laminated lumber and
for many other structural applications.
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New lamination and
finger-jointing technologies are increasing the use of New
Zealand pine in a wide range of products - from small mouldings
to huge engineered beams.
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New Zealand pine is
being successfully used for a wide range of interior fittings
and fixtures, including: windows, doors, frames and jambs,
mouldings, stairs, cabinetry and bench tops.
TREATMENT
Preservative treatment to the strict hazard class
specifications, allow the New Zealand industry to give service life
guarantees for external use products.
A number of properties of New Zealand pine contribute to the ready
acceptance for these products.
TEXTURE & APPEARANCE
One of its unique properties is its uniform density, i.e. the
small variation in density between spring wood and summer wood
within a growth ring. It is this property which confers on New
Zealand pine its excellent machining, painting and staining
properties.
Consisting mainly of white sapwood, with prominent fine resin
canals, it presents a uniform appearance with little colour
variation between pieces. This is an advantage for subsequent
finishing.
MACHINING
Comprehensive tests undertaken have shown that New Zealand pine
has machining properties (cross-cutting, turning, planing, moulding,
boring, sanding) equal to or superior to many of the internationally
traded softwoods. Its fast growth does not adversely affect its
working properties and good results can be obtained with all types
of hand and machine tools.
FINISHING
The full range of interior and exterior stains, oils, varnishes
and paints may be used on New Zealand pine. The absence of high
concentrations of extractives prevents any incompatibility with
finishes and eliminates the need for special primers. A very high
standard of finishing can be obtained.
The wood can be stained to resemble a wide range of traditional
timber species.
FASTENING
Being of medium density and even texture and having a good
resistance to splitting, New Zealand pine can be nailed particularly
well. The same properties allow the production of efficient joints
using other systems, e.g. screws and proprietary connections.
Low extractives content and uniform density allow achievement of
above-average glued connections e.g. dowels and finger-joints. The
high strength of glues dowel joints is due to the contribution from
the end grain to the joint.
DIMENSIONAL STABILITY
This is a crucial wood property for interior fittings and
joinery uses. New Zealand pine has a low shrinkage which contributes
to its stability.
However, stability is also affected by a number of other properties,
including: equilibrium moisture content, straightness of grain,
spiral grain, rate of moisture uptake, permeability to liquids and
gases.
Long term movement is the property which best describes the
dimension changes which occur when joinery is exposed to dry summer
conditions and later to wet winter conditions.
The dimensional response of cladding and joinery when exposed to
fluctuating weather conditions, such as alternating rain wetting and
sunshine, is best described as short-term movement.
Because of the presence of spiral grain, the juvenile wood of New
Zealand pine should not be used where stability is vital to
performance.
Dimensional performance can be increased by use of finger-jointing,
and/or lamination. Such highly processed laminated, finger-jointed
clear products are used widely in Japan where a maximum stability is
required.
DURABILITY
New Zealand pine must be preservative-treated for exterior uses.
However, it is one of the most permeable wood species and can,
therefore, be acceptably treated by pressure impregnation, double
vacuum and simple immersion methods. LOSP treatments are very
successful for joinery.
WOOD BENDING
A process developed to bend solid pine timber and MDF to the
consistent requirements of furniture manufacturers, thus creating an
entire range of design possibilities.
The Woodform process is both cost and time effective for the
manufacturing of existing products, and it creates the potential for
more inspired, imaginative furniture design and production; options
previously uneconomic now achieve maximum value added potential.
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