Shining Gum for Farm Forestry

Note Number: AG0849
Published: September 2000
Updated: February 2009

Shining Gum is a popular plantation tree for woodchip and sawn timber in the colder and high rainfall areas of Australia. This is due to its very fast growth rate, its ability to grow in cold and dry areas at high elevations, and its many favourable timber characteristics.

The name nitens is Latin for shining, polished, bright. This refers to the leaves, buds and the bark. The fruits in particular have a distinct glossy, varnished appearance

Natural occurrence

Shining Gum occurs naturally in scattered pockets in the higher altitudes (800-1300 m) of the Victorian Alps (eg. the Baw Baws, Mt. St Leonard), along the coastal escarpment of the southern tablelands of NSW and in north central NSW (Barrington Tops).

Provenances

Due to its scattered natural occurrence, there are many provenances in existence. Improved seed orchard material is available, with selections mainly concentrating on growth rates and fibre properties such as basic density and pulp yield. There are provenance differences in their resistance to foliar insect attack due to genetic variation in insect repellent polyphenolics in leaves. Breeding for sawn timber traits has not yet occurred.

Site requirements

Shining Gum requires sites with a minimum annual (not average) rainfall of 700 mm/yr, and distribution from a slight winter maximum, to more or less uniform. It prefers cool wet slopes, with best growth occurring on moist loams in higher elevations. It is tolerant of exposure, snow and frosts with seedlings having a very high frost resistance.

During the drought years of 2006/07, many Shining gum plantations in North East Victoria and Gippsland have had substantial deaths. Most affected drought-stressed trees have been attacked by wood borers.

Growth rates

Shining Gum trees can reach heights of 70 m, and diameters of 1-2 m at breast height. It has good form (even when open grown), having a straight bole up to two thirds the height of the tree.

It can be extremely quick growing, with growth rates of 50 m3/ha/yr being measured under ideal conditions. More commonly, 20-30 m3/ha/yr on average to good sites has been achieved.

Management

Shining Gum is generally a poor self-pruner and some provenances tend to fork if the growing point is damaged. Early form pruning will be needed if this occurs. Where clear-wood is being produced, regular lift pruning will also be required to minimise the size of the knotty core.

Under good growing conditions, sawlogs can be produced in 15-25 years and pulp logs in 10-15 years. Improvements in technology are leading to sawn-timber being produced from small diameter logs. This process has commenced in Tasmania where EcoAsh is being produced from trees under 10 years old.

Shining Gum will respond well to fertiliser application, particularly phosphorus and nitrogen, if these elements are at low levels in the soil. The micronutrient boron has been found to affect tree form significantly where deficiencies occur, particularly on ex-pasture sites, causing distorted and stunted growth. In coastal areas, zinc and copper responses have also been observed.

Pests and diseases

Young plantations of Shining Gum have so far shown little incidence of endemic insect pests. They can be susceptible to Autumn Gum Moth larvae and other leaf eating beetles such as paropsis, but generally insects are not a major concern. Gum Tree Scale is one of the more serious pests causing dieback and even death of young trees. The appearance of many ants, flies and other insects on the trees feeding on the honeydew secreted by the scale, is often the first indication of a scale infestation. Leaves and the ground may become black from the sooty mould which also grows on the honeydew. Provenances vary in their susceptibility to insect attack. It is the juvenile foliage that is most susceptible to insects and animal browsing. Management to increase early growth and reduce the time for mature foliage to develop, will help control outbreaks. Autumn Gum Moths and leaf eating beetles such as paropsis spp and liparetrus spp (Spring beetles) have been observed to attack some plantations.

Shining Gum is susceptible to Phytophthora root rot fungus, and soil should be tested prior to planting. It is moderately tolerant to root rot fungi via stem injury, but susceptible via root injury. Fungal pathogens entering through the bark have caused significant mortality when young Shining Gum are stressed.

Root coiling (and subsequent strangling), root death and fungal infections can be a problem in Shining Gum. This causes death of trees after a few years. To ensure root coiling does not occur, seedling growth in pots and subsequent planting must be undertaken with care.

Uses

Timber from Shining Gum has a wide range of uses, from pulp to sawn products. It is a good quality pulping species, although the wood is of slightly lower density than Tasmanian Blue Gum and therefore gives lower pulp yields. When plantation grown, it has potential to produce sawlogs of select grade material if pruned. The timber is used for joinery furniture, framing and flooring. The pale wood of young trees means the timber can be interchanged with Mountain ash.

Wood quality

The heartwood is a straw colour with pink or yellow tints, and the sapwood is not always easy to distinguish. The texture is medium with a straight grain. Pin-hole borer holes and associated black stains of "pencil streak" are often present, giving otherwise attractive timber a very speckled appearance.

Green density of the timber is 1050 kg/m3 and air dry density at 12% moisture is about 700 kg/m3. The wood is not as hard as Blue Gum, being moderately hard at 5.8 kN when dry. The heartwood of Shining Gum is not sufficiently durable for external use (Class 4), and the sapwood is susceptible to lyctid borers.

Drying characteristics

The wood from Shining Gum is difficult to dry, with moderate shrinkage and high cell collapse necessitating reconditioning. Improvements in the technical aspects of drying timbers will reduce the impact of these problems on timber from younger plantation-grown native hardwoods.

Summary

Shining Gum is an excellent fast growing plantation species when grown in areas of high rainfall and cooler temperatures and high altitudes. It is ideally suited for pulp production in these areas.

References

Bootle, K.R. (2004). Wood in Australia. Types, properties and uses. Second edition. McGraw-Hill Book Co, Sydney.

Borschman, R., (May 1996). Report on the Monitoring and Evaluation of Farm Forestry Sites in North East Victoria. North East Farm Forestry Program, Centre for Forest Tree Technology.

Costermans, L., (1994). Native Trees and Shrubs of South Eastern Australia. Lansdowne Publishing Pty Ltd, Sydney.

Hall, N., Johnston, R.D., & Chippendale, G.M. (1975). Forest Trees of Australia. Australian Department of Agriculture, Forestry and Timber Bureau, Australian Government Publishing Service, Canberra.

Hillis, W.E. & Brown, A.G., Ed. (1984). Eucalypts for Wood Production , CSIRO Australia.

Johnson, I.J., (1996). Growth and Form of Eucalyptus nitens progenies in New South Wales, and selection strategies for a seedling seed orchard. Australian Forestry Vol 58. No 4. pp 162 - 170.

Pederick (1997) Natural variation in shining gum (Eucalyptus nitens). Australian Forest Research Vol 9, pp 41-63.

Phillips, Charlma(1996). Insects, Diseases and Deficiencies associated with Eucalypts in South Australia. Primary Industries, South Australia.

Washusen, R. (1995). Farm Forestry Species for the Benalla Landcare Farm Forestry Group. Benalla Landcare and Farm Forestry Group, Benalla.

Acknowledgements

This Agnote was developed by Philippa Noble, September 2000.

It was Reviewed by:

Philipa Noble, Farm Services Victoria Farm Forestry. January 2008.

Philipa Noble, Farm Services Victoria Farm Forestry. February 2009.