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MANAGEMENT OF INVASIVE ALIEN PLANTS

 

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Announcements

WfW regional-level historical database - (this will open a Excel document)
Working for Water Position Paper on Biocontrol - (this will open a PDF document in a new window)
WfW Approach to work on private land - (this will open a PDF document in a new window)
WfW Project Operating Standards - (this will open a PDF document in a new window)

Any control programme for alien vegetation must include the following 3 phases:

  • Initial control: drastic reduction of existing population
  • Follow-up control: control of seedlings, root suckers and coppice growth
  • Maintenance control: sustain low alien plant numbers with annual control

MECHANICAL & CHEMICAL METHODS

Where trees cannot be utilised (on steep slopes), do not fell trees, control them in situ.

Select from the following options:

  • Basal bark: Application of suitable herbicide in diesel can be carried out to the bottom 250mm of the stem. Applications should be by means of a low pressure, coarse droplet spray from a narrow angle solid cone nozzle.
  • Hand pull: Grip the young plant low down and pull out by hand (using gloves).
  • Ring barking: Bark must be removed from the bottom of the stem to a height of 0.75-1.0 m. All bark must be removed to below ground level for good results. Where clean de-barking is not possible due to crevices in the stem or where exposed roots are present, a combination of bark removal and basal stem treatments should be carried out. Bush knives or hatchets should be used for debarking.
  • Frill: Using an axe or bush knife. Make angled cuts downward into the cambium layer through the bark in a ring. Ensure to effect the cuts around the entire stem and apply herbicide into the cuts.

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The Frilling Method

Where trees can be felled and removed use chainsaws, bowsaws, brushcutters or cane knives.

  • Cut stump treatment: Stems should be cut as low as practical as stipulated on the label. Herbicides are applied in diesel or water as recommended for the herbicide. Applications in diesel should be to the whole stump and exposed roots and in water to the cut area as recommended on the label.
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  • Stem injection: Punch downward slanting holes into the main stem using a sharpened metal spike. Space holes around entire circumference of lower stems. Inject the herbicide directly into the plant – ensuring to inject around the stem. Follow label recommendations - For invasive cactus species.
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Management treatments summary guide for terrestrial & aquatic IAPs
American bramble
Australian myrtle
Barbados gooseberry
Beefwood
Black wattle
Blackwood
Bluegums
Brazilian pepper tree
Bugweed
Cacti spp
Camel thorn bush
Cluster pine
Golden wattle
Green wattle
Grey Poplar
Guava
Honey Mesquite / prosopis
Inkberry
Jacaranda
Kudzu
Lantana
Long-leaved wattle
Mauritius thorn
Peanut Butter Tree
Port jackson willow
Queen of the night
Red sesbania
Rock Hakea
Rooikrans
Silver wattle
Sisal
Syringa
Triffid weed
... Click here

BIOLOGICAL CONTROL


Biocontrol dossiers (for 22 species in South Africa)

NOTICE : You'll need Acrobat  Reader to view these files. Download and install Acrobat Reader here.

Click here to find out where to obtain Biocontrol Agents

Indigenous Replacement Plants in the KZN region - (this will open a MS Word document in a new window)

Activity sampling

The national Working for Water programme has been clearing invading alien plants since 1995. The programme grew from 20 projects in 1996 to over 300 projects currently. This rapid growth hindered the standardisation of clearing methods and norms between regions. The result is that Working for Water has a wide range of efficiency and productivity values across the country.

The Activity Sampling programme was introduced to establish realistic norms with regard to clearing methods and productivity. The programme was initiated with the following objectives:

  • To raise recommendations for increasing productivity in the Working for Water programme
  • To establish realistic norms with regard to person days per hectare
  • To describe clearing methods used
  • To define size and density classes
  • To establish standardised clearing methods per species and per operation

The Mondi Forests Work Study Department is responsible for the implementation of the activity sampling programme in each region. Evaluators are allowed to visit teams in the field and to make accurate assessments as to where there might be areas where improvement could lead to higher productivity.

In specific areas where activity sampling was done, productivity rose from an average of 65% to more than 80%. Increases in productivity averages on this scale impact significantly on projects such as Working for Water. Consider, for example, the impact a 15% increase in productivity would have on a project with a budget of R42 million!

Click here to visit the Plant Protection Research Institute Website: http://www.arc.agric.za/v-arcroot/institutes/ppri/main/home.htm


Relevant Acts dealing with Invasive Alien Plant Control & Wetland Rehabilitation

Implemention

Applications forms to request Clearing