Shrubby Forest

Shrubby forestThe understorey of shrubby forest is dominated by small-leaved shrubs more than 2 m tall, such as tea-trees (Leptospermum spp.) and wattles (Acacia spp.). The canopy can be dominated by most types of eucalypt forest, including black gum (Eucalyptus ovata), white gum (Eucalyptus viminalis), black peppermint (Eucalyptus amygdalina), highland cabbage gum (Eucalyptus pauciflora), blue gum (Eucalyptus globulus), ironbark (Eucalyptus sieberi), stringybark (Eucalyptus obliqua), gum-topped stringybark (Eucalyptus delegatensis), snow gum (Eucalyptus coccifera), Smithton peppermint (Eucalyptus nitida), and white peppermint (Eucalyptus pulchella).

Shrubby forest is usually found in moisture conditions that are intermediate between those of wet forest and either heathy forest or grassy woodland and forest.

Where to see shrubby forest

Shrubby forest is common and widespread in Tasmania. A large proportion of the forest on the south-facing slopes of the foothills of Mt Wellington and much of the forest around Launceston is shrubby forest.

Biodiversity values of shrubby forest

Most types of shrubby forest are well reserved, and most have escaped significant clearing for agriculture and development.

Shrubby forestHowever, little remains of the shrubby forests dominated by black gum, and those dominated by blue gum have been heavily cleared. Blue gum forests are extremely important for the survival of the swift parrot, a species considered vulnerable to extinction. Much of the unreserved forest is used for timber production. Relatively little shrubby forest is used for stock grazing, and when used it is mainly for shelter.

Shrubby forests are generally rich in Tasmanian endemic birds and marsupials. Shrubby forests that are particularly important for biodiversity survive in a few small remnants on lowland basalt in the north-east and north-west of the state.

Refer to Threatened Species for more information.

Management issues in shrubby forest

The best management regime for shrubby forests will depend on the condition of the bush. The key management issues in shrubby forests are:
  • Fire management. Inappropriate fire regimes can lead to the conversion of shrubby forest to other vegetation types. In some situations this may be seen as desirable (e.g. conversion to grassy forest which generally has a greater diversity of plant species than shrubby forest). However, a shrubby understorey has been shown to support a diversity of native birds.
  • Weed invasion. This will be a problem in bush in good or poor condition. However, it is something to watch for in bush in excellent condition in order to prevent future weed invasion and subsequent degradation. In particular, woody weeds such as boneseed, cotoneaster, hawthorn, gorse and broom are a serious problem in shrubby forest.
If threatened species are present you should consider their needs. These needs may conflict with other aspects of management. Some threatened species are found in remnants that are in poor condition because the past management regime has favoured their survival. If the management regime is changed these species may be lost.

Managing by condition

The best management regime for shrubby forest will depend on the condition of the bush. Management guidelines based on the condition of the bush are given below. However, the specific needs of threatened plants may override these recommendations. If you are unsure what condition your bush is in refer to Condition of Your Bush.

Excellent condition

Shrubby forest in excellent condition is characterised by:
  • A healthy shrub layer.
  • Low levels of weed invasion.
Bush in excellent condition is an asset. Maintain your current management regime. There is no need to change your management practices unless there is an obvious reason to do so.

If there are any signs of weed invasion, an active weed control program, particularly of gorse and broom, may be needed to maintain the integrity of shrubby bush in excellent condition. Only burn gorse if you are able to apply herbicide following the burn. Shrubby forest may become wet forest in the natural process of succession following fire. If you do not want this to occur burn at least once every 40 years. However, do not burn any shrubby forests that are higher than 900 m above sea level.

You may wish to limit access to sensitive areas through strategic fencing. This includes areas with grazing-sensitive threatened species, areas where there is a high risk of erosion such as in gullies, and where the regeneration of trees and shrubs is needed.

Good condition

Shrubby forest in good condition is characterised by:
  • Some old and dying small-leaved shrubs.
  • Weed invasion. Gorse can be a major problem in shrubby forests. Only burn gorse and broom if you are able to apply herbicide following the burn.
If the small-leaved shrubs are dying through old age, burning the understorey will generally result in their regeneration. However, do not burn any shrubby forests higher than 900 m above sea level. Burning can also be useful for killing some woody weeds such as cotoneaster and hawthorn. Other woody weeds will require follow-up work after fire, using hand pulling where possible (e.g. South African boneseed) or an application of herbicide.

Poor condition

Shrubby forest in poor condition is characterised by:
  • Extensive areas of bare ground.
  • No regeneration of trees and shrubs.
  • Severe weed problems.
Burning the understorey of shrubby forest in poor condition will result in the regeneration of trees and shrubs. However, do not burn shrubby forests if they are higher than 900 m above sea level. Burning will also kill the woody weeds such as cotoneaster and hawthorn. Some woody weeds will need follow-up work after burning. For example, some weeds will need to be pulled by hand (e.g. South African boneseed) or given an application of herbicide.

Consider rehabilitating bush that is severely degraded, particularly if there is extensive erosion. Refer to the publication Revegetating Your Farm (PDF).

Grazing

  • There will be little economic return from grazing shrubby forest. Most of the vegetation is unpalatable and too tall for stock to reach.
  • If the remnant is in good condition maintain your current management regime unless there is an obvious reason to do so.
  • Shrubby bush can provide shelter for stock. Nevertheless, exclude stock if possible.
  • Do not allow stock access to the bush soon after burning. Stocking too soon after fire will impede the regeneration of new plants.

Fire

  • Do not burn shrubby forest that is higher than 900 m above sea level.
  • Patch burn to favour target species. The fire pattern should favour the persistence of threatened plant and animal species.
  • Burn every 20-40 years. More frequent fires will often prevent a shrubby layer forming. Less frequent fires may convert the bush to wet forest.
  • Moderately hot burns are better than cool burns. Burns should at least remove all the ground litter.
  • Only burn gorse or broom if you are able to apply herbicide following the burn.

Weeds in shrubby forest

Woody weeds such as cotoneaster, hawthorn, boneseed, blackberry, gorse and broom are the most serious weeds in shrubby forests.

See also Weeds on this site for more information.

Back Home