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Log Density

The variety of log types available from our plantations gives the buyer the opportunity to specify logs according to requirements.

Wood Quality

Radiata Pine Outerwood DensityThe quality of plantation-grown trees is influenced by genetic selection, silvicultural practice, site selection and rotation age. Over the last 60 years there have been many changes in forestry practices which have resulted in greater control over the type of wood produced. Our pine forests are established with genetically selected stock and managed to provide a predictable, premium quality log resource for a wide range of world markets. Ideal growing conditions and appropriate management permit the harvesting of large logs (up to 80cm diameter) on rotations of approximately 30 years.The logs are typically healthy, containing no decay, internal splits, or growth stresses.

Climatic conditions as well as prudent management of our plantations ensures the very best Radiata Pine available in New Zealand.We have found that there is a consistent increase in density outward from the pith, with a tendency to level out as the tree reaches 15 to 20 years.The corewood, usually the five innermost rings, is often of a low density with shorter fibres and higher longitudinal shrinkage than the outer wood.

This density of the outer wood while varying from tree to tree is closely related to the mean annual temperature of where it is grown.

You will see from the chart below that Croft trees grown in the Northern parts of New Zealand and at low altitude has a far higher density and consistently higher clearwood strength.

Climatic & resource management practices combine to make our products the best in New Zealand

SOME TYPICAL PROPERTIES OF RADIATA PINE
Source (Forest Service
Conservancy)
Density at 12%
Moisture
Content (kg/m3)
Modulus of
Rupture (MPa)
Modulus of
Elasticity (GPa)
Hardness (kN) Percentage
Shrinkage from
Green to 12%
Moisture Content
G D G D G D R T
Auckland North 609 49.4 112.1 7.8 12.0 3.1 6.1
Rotorua 496 37.4 84.3 5.7 8.4 2.4 3.5
Wellington 477 36.2 85.7 5.7 9.2 2.0 3.2
Nelson: Inland 515 36.0 82.8 4.7 7.8 2.5 3.9
Coastal 600 46.9 103.3 7.2 10.6 3.1 5.5
Westland 476 37.0 79.2 4.8 7.8 2.5 3.1
Canterbury 464 32.8 71.2 3.9 5.9 2.3 3.5
Southland 463 35.8 86.8 4.5 7.8 2.6 4.3
Mean 520 39.5 89.9 5.8 9.0 2.5 4.2 2.1 3.9

• G = green timber; D = timber at 12% moisture content; R = in radial direction;T = in tangential direction • Strength values refer to 20mm clearwood specimens • For allowable design stresses see NZS 3603 “Timber Design Code” (1981). • References: Density and strength values are from Bier, H. “The Strength Properties of Small Clear Specimens of New Zealand Grown Timber”, FRI Bulletin No. 41, Forest Research Institute, NZ Forest Service, Rotorua 1983, Shrinkage values are from “The New Zealand Forest Service Timber Design Data Handbook, 1970”. • Conservancy and mean values above are weighted averages according to the number of test results, and do not purport to be representative of production as a whole.