New Zealand radiata pine
is widely known as an extremely versatile lumber, suitable not only for packaging but also for use in furniture, doors, floors and the list goes on. The following description of the physical characteristics is intended to provide preliminary technical advice for current and intended users. More Radiata Pine Information can be found below.
Density of Radiata pine
Medium density ensures versatility. Average tree density (oven dry weight-/green volume) is lower near the pith and higher near the bark. It varies with site and age from around 390kg/m3 for 25-year-old trees on a low density site to around 460kg/m3 for 45-year-old trees on a high density site. A 30-year-old tree on a medium density site has a density of around 415kg/m3.
Strength of Radiata pine
The Timber compares favourably with other species in bending strength, bending stiffness and fastening. Under JAS 600, radiata is rated to equal to spruce-pine-fir, and better than western red cedar. Shear strength is excellent – a factor of its uniform texture.
Permeability of Radiata pine
Radiata Pine forms heartwood at about 15 years and progresses slowly. At 30 years about 20% of the stem is heartwood. High permeability of the sapwood makes it easy to dry and treat with preservatives. Heartwood is less permeable than sapwood, but dries readily and can also be effectively preservative treated. When exposed to the possibility of decay the timber should be preservative treated.
Although sapstain fungi will colonise and discolour untreated wood. Modern treatments can effectively prevent sapstain.
Shrinkage and Stability
Radiata Pine has good stability and low to moderate shrinkage. Radiata Pine compares well with most other softwoods. from green to dry (12% mc) it shrinks, on average, 3.9% tangentially and 2.1% radially, which is slightly less than Douglas fir. Stability can be improved by high temperature drying or quarter sawing.
Colour of Radiata Pine
Radiata has a light coloured sapwood with slightly darker heartwood. Exposure to the sun leads to a yellowing of both heartwood and sapwood. No special finishing techniques are needed for a uniform finished appearance.
The mechanical properties of sawn lumber are closely related to knot size and density. Because density increases with distance from the centre of the tree, mechanical properties follow that characteristic. Properties, particularly density, increase as ring width decreases, (ring width generally decreases with distance from the centre of the tree). Typical mechanical properties for clear grade, 30-year-old material (20mm standard specimens) are shown below.