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Forestry Fact Sheet Number 1

Radiata pine

There is a thriving forestry and forest products industry based on radiata pine (Pinus radiata) in South East South Australia and Western Victoria. The total area of the radiata pine plantation in the area known as the Green Triangle Region is about 175,000 ha. Most of these plantations are in South Australia.

The main products produced from radiata pine are sawn timber, plywood, pulp, posts and export woodchips.

Tasmanian blue gum

There is a large resource of Tasmanian blue gum (Eucalyptus globulus) plantations grown specifically for pulping and for export markets. Tasmanian blue gum and radiata pine have similar site requirements, although Tasmanian blue gum is considered more susceptible to drought, and grows best in a narrower range of sites than radiata pine.

Other species

Farm plantings to produce similar products using other species must be considered speculative at this stage as there is little known of their growth performance in the South East. However, there is some likelihood of commercial plantings of some species if sufficient developmental work is done and if a reasonable area (5,000 ha) is planted to a particular species. 

Site Requirements

Climate

The plantation industry has concentrated on areas with rainfall in excess of 650 mm, as this has been traditionally considered necessary for ‘commercial’ plantations. Radiata pine within this zone grows at an average MAI (Mean Annual Increment) of 20-23 cubic metres (tonnes) per ha per year and this gives a commercial return on investment. Growth rates for areas of less than 650 mm annual rainfall are generally less than this but there has been very little measurement of such plantations to determine growth rates. Observations of pine plantations in the Lucindale, Western Flat and Padthaway areas indicate that there is potential for radiata pine and Tasmanian blue gum in low-rainfall areas, albeit with reduced growth rates.

Soil

The predominant soils used for forestry are the sands. Generally a minimum of 50 cm of sand to clay is required to ensure adequate moisture-holding capacity and stability for the trees. Impervious grey, white and black clays tend to impede drainage and root development and these water logged sites are generally not suitable. Radiata pine and Tasmanian blue gum do not tolerate saline conditions. Many sandy soils are infertile (particularly where they originally grew low stringy bark scrub) and depending on previous fertiliser history, often require fertiliser. 

Establishment and management

Site Preparation

The main need for cultivation is where mounding is required on the wetter sites. Large mounds help to keep seedlings out of the water and they also provide a stimulus to growth. Drier sites can be hand or machine planted without prior cultivation, although where there is dense bracken, ripping of planting lines with a ‘rabbit ripper’ may be necessary. This is standard practice for radiata pine, but not proven with Tasmanian blue gum. Some sites need ripping where there is an impervious hardpan or clay layer within 50-100 cm of the surface. 

Weed Control

The key to good establishment is good weed control. Generally, complete weed control is recommended except in areas where soil drift and sand-blasting of seedlings could occur. In these areas 60 - 80 per cent strip weed control is preferred but trees must be planted in the middle of the weed free strip. Weed control regimes are site and weed specific so cannot be given in detail here. As a general guide, bracken and sorrel control are needed in the summer prior to planting, followed by pre-planting weed control in May or June. Pines will need a second year weed control, but Tasmanian blue gums can often be grazed by sheep after the first year if done carefully, which eliminates the need for a second weed control. 

Planting

Planting is generally done in June-July, using either a tractor-mounted machine or hand planting for pines and a ‘Pottiputki’ type tool for eucalypts. Seedlings should be of superior genetic stock, and with Tasmanian blue gums, provenance of seed is important. Stocking rates are generally of the order of 1600 trees/ha for pines and 1000 trees/ha for eucalypts. Seedling costs are in the order of $250-$350/ha. Growers need to be aware that mechanical harvesting will be more economic if stands of 20 ha or more are planted. Smaller areas are often difficult to get logged, due to the high cost of transporting harvesting machinery to the site. 

Nutrition

Neither radiata pine nor Tasmanian blue gums have high nutrient demands, but adequate nutrition including trace elements is necessary. Generally growth is monitored and fertiliser applied as required. 

Pruning

Pruning is generally unnecessary except on external trees to maintain access and help with utilisation of these rough edge trees. In some forestry regions radiata pine is thinned early (age six) and pruned to produce high-quality clearwood, called the ‘direct regime’. This is not widely done in this region as there is currently no premium market for the wood. This regime may well be economically rewarding even without a premium for clearwood as it enables the rotation length to be reduced from 35-40 years to 20-25 years. 

Fire Protection

A minimum 10m firebreak/access track should be left around each plantation, with internal access breaks at least every 400m (for logging and fire access). The breaks should be grazed or slashed annually prior to summer to help control fires. Local Government generally has planning regulations regarding firebreaks. 

Sale of Products

Radiata pine

Standard forestry practice in the region is to thin plantations at 5- 7 year intervals starting at age 10-15 (depending on growth rate) and clearfell at age 30-40. 

The standard pricing practice is for the purchaser to pay the grower a price for the products that are harvested. The purchaser pays for cutting, extraction and haulage of the products. With a thinning operation it is recommended to have the stand tree marked (that is marking which trees are to be removed). The grower can get a contractor to do this. The grower is expected to provide adequate access roading for logging machinery.  The product price will depend on access and haulage distance. If access is difficult and or haulage distance is great then the product price will decrease. The overall return depends on the product price and volume of products cut. There is no guaranteed or minimum price and the grower should look at all available marketing options. 

The first commercial thinning products are generally pulpwood and or post material. The capacity for private growers to sell these products varies with the general market, and is enhanced if the plantation is of economic harvesting size and of even quality. Current outlets for this material are in the Lower South East. 

Subsequent thinnings have higher proportions of higher-value log, which are relatively easy to sell, and the major return is at time of clearfelling. Returns on investment are extremely variable as they depend on growth rate, establishment cost, fertiliser needs, thinning history, rotation length, markets and location, size and accessibility of the plantation. 

As a rough guide, the following returns are shown for Site Quality (SQ) 3 (above the region average) and SQ 4 forest (below the region average) in the >650 mm rainfall zone using the best available product prices. 

Table 1. Returns from a well managed forestry plantation for two Site Qualities.

 

Site Quality 3
Thinning	Age	Yield (m3/ha)	Return/ha
T1	10	100	$1030
T2	16	70	$990
T3	22	77	$1600
T4	29	111	$3200
Clear Fell	36	583	$22,720
Total			$29,540

 

Site Quality 4
Thinning	Age	Yield (m3/ha)	Return/ha
T1	12	117	$1100
T2	19	83	$1170
T3	26	81	$1740
Clear Fell	34	489	$13,120
Total			$17,130

NB These are current day prices and do not allow for inflation

 

The overall economics depend greatly on the establishment cost. Poor establishment can easily reduce the Site Quality by one or more classes with dramatic effects on future returns.

Tasmanian blue gum

Some growers are speculating on the future demand and growing Tasmanian blue gum without a contract. Tasmanian blue gum harvesting and marketing is currently begun and under development. This industry is in its infancy with regards to the sale of products by private growers. 

Other Species with Forestry Potential

There have been many other species mooted for forestry in this region. Some of them are listed in Table 2 below.

Table 2. Other species with forestry potential in the Green Triangle Region.

 

Common Name	Scientific name	Brief description
Black wattle	Acacia mearnsii	Firewood potential
Blackwood	Acacia melanoxylon	Appearance grade timber, high rainfall, susceptible to borers
Cypress	Cupressus species	Sawlog potential
Spotted gum	Corymbia maculata	Sawlog potential, frost sensitive
Red gum	Eucalyptus camaldulensis	Very slow growing and insect susceptible, waterlog tolerant
Flooded gum	Eucalyptus grandis	Sawlog potential with pruning
Sydney blue gum	Eucalyptus saligna	Sawlog potential with pruning
Manna gum	Eucalyptus viminalis	Sawlog potential provenance specific
For drier areas <600mm
Sugar gum	Eucalyptus cladocalyx	Sawlog and firewood potential
Flat topped yate	Eucalyptus occidentalis	Firewood potential
Brutian pine	Pinus brutia	Sawlog and woodchip
Canary Island pine	Pinus canariensis	Sawlog and woodchip
Maritime pine	Pinus pinaster	Sawlog and woodchip

For growers seeking a commercial return, all of these species should be considered speculative as there are no locally established markets. There has been some developmental work on genetic selection of the maritime pine, but very little on the others. Since 1997 substantial testing has been done on some of these species . Hybrid eucalypts have also been trialled. 

Firewood production has some potential, particularly where transport to markets is convenient. It is important to realise that over half of the weight is lost when the wood is dried. 

Some eucalypts can be preservative treated for fence posts, and have the advantage of regrowing from coppice.

Further Reading

A useful reference book on farm forestry in South Australia is: 

“Farm trees for the Mount Lofty Ranges - A regional agroforestry handbook” by Peter Bulman, 1995. Published by Primary Industries SA.

 

For further information please contact PIRSA Forestry

 

 

Disclaimer: While this publication may be of assistance to you, the government of South Australia and its officers do not guarantee that it is without flaw of any kind or is wholly appropriate for your particular purpose. The Government therefore disclaims all liability for any error, loss or other consequence that may arise from you relying on any information in this publication.

 

 

Last Revised February 2008