A versatile wood
Radiata pine wood is even-textured and easy to slice, peel, mould, turn, sand, plane, glue, stain and paint.
When planed to a smooth finish, the wood is creamy-coloured, with stripes created by the contrast between wood grown early in the annual growth season (softer and paler) and that grown later (harder and darker). The wood darkens over time with exposure to light.
Bark from harvested pine trees was once viewed as a waste product, but is now used for fuelling kilns and dryers at wood-processing plants, and made into plant-propagating mixes, mulches and composts. An extract from the bark is even used in a dietary supplement, enzogenol.
The wood is of medium density (350–450 kilograms of dry weight per cubic metre of green volume), which means that it is light in weight, relatively soft and not very strong. It is easily penetrated by preservatives and pulped by chemical or mechanical processes.
Wood density increases with tree age, and with the mean annual temperature of the site – leading to a regional differentiation in wood quality. The densest wood is from Northland, the lightest wood from Southland or high-altitude areas, such as the central North Island.
The core of older trees (heartwood) has some undesirable features that can cause structural weakness and warping.
Heartwood is dark, contains resins and is dry. It starts to develop in the centre of trees at around 10 years, and is usually confined to the five innermost rings. Radiata pine heartwood is not highly regarded as it causes colour problems in pulp, detracts from the appearance of natural finishing timbers, and is not readily permeable by preservatives.