Weeds
Mechanical Cultivation
Mechanical Cultivation can be effective if timely. Cultivation immediately prior to planting will reduce competition for a time and allow seedlings to become established but subsequent growth produces competition.
Slashing and brushcutting is often employed to suppress woody weeds.
Herbicides
Herbicides are generally the most effective means of weed management as they can prevent germination and competitive growth.
A range of residual and knockdown herbicides is available to forest growers. The method of application depends on the chemical being used.
Some are suited to delivery by air (e.g. helicopter), from a tractor by boom spray or manually, from knapsacks or by application to a fresh stump. Various laws and Codes of Practice regulate the use of herbicides in forestry and agriculture.
The Australian Pesticides and Veterinary Medicines Authority (APVMA) is the statutory authority responsible for the evaluation of chemical products and the registration of permitted use in Australia. All herbicides must go through APVMA's rigorous testing procedures to ensure they meet high standards for effectiveness and for safety in use.
Herbicides used in forestry are widely used throughout the world and in agriculture. They have applications in field cropping (potatoes, onions, peas, canola, cotton, rice, and sugarcane), pasture production, horticulture (vineyards and orchards), in home gardens, and in some aquatics treatments (in lakes and streams or on roadsides and around buildings).
Forestry Tasmania elects not to apply herbicides in the triazine group.
Biological Agents
Biological agents have been introduced to parts of Tasmania for the control of the weed species, Broom and Gorse. They are demonstrating some promise but will need to be used in conjunction with other methods for maximum effect.
Weed competition is most severe until canopy closure is attained. Once the ground is completely shaded weeds have difficulty establishing and competing with the tree crop. It will usually take several years before the tree canopy is closed. In the interim post-planting weed control is customary.
Access further information on weeds, pests and diseases in Tasmania at the Department of Primary Industries, Water and the Environment (DPIWE), or for information on chemical registration and evaluation in Australia, contact the Australian Pesticides and Veterinary Medicines Authority (APVMA)