Invasive Alien Plant Management

Invasive Alien Plant Management

Mondi Ltd

Invasive Alien Plant Management

in Conservation Areas

Compiled by: J Shuttleworth

March 2010


Integrated Management System

/ Approval
Environmental Manager

Environmental Guideline

/ Doc No: EG-01
Issue Date: 10/03/2010 / Rev: 0
TITLE: / Invasive Alien Plant Management in Conservation Areas

Table of Contents



2.1Long Term Resource Plan (LTRP)......

2.2Annual Plan of Operations (APO)......

3.Control methods......

3.1Chemical Control......



4.1Dedicated teams......

4.2Treatment methods......

4.3Timing of follow-up......


5.1Monthly against APO......

5.2Operational efficacy......

5.3Annual IAP assessments......

6.Awareness & training......



6.2.1Emerging invasive alien plants......




Integrated Management System

/ Approval
Environmental Manager

Environmental Guideline

/ Doc No: EG-01
Issue Date: 10/03/2010 / Rev: 0
TITLE: / Invasive Alien Plant Management in Conservation Areas

1. Background

Invasive alien plants (IAPs) are recognized as one of the biggest threats to South Africa’s biological diversity, water security, the ecological functioning of natural systems and the productive use of land. As a result of this, in South Africa, it is a legislative requirement that IAP species, as identified by the Conservation of Agricultural Resources Act 43 of 1983 (CARA) and the National Environmental Management: Biodiversity Act 10 of 2004 (NEMBA), are controlled. Also, certification with the Forestry Stewardship Council (FSC), compels Mondi to address IAP’s under Principle 6, Criterion 6.3.

Notwithstanding the legislative and certification requirements, Mondi is committed to dealing with IAP’s and have added IAP control as a performance requirement (PR 11.1) in the Mondi Sustainable Development Management System (SDMS, Rev A, June 2009): “The spread of alien invasive plant species in plantation areas does not exceed accepted norms and Mondi’s minimum requirements”. Mondi aims to manage all non commercial areas to a maintenance phase[1] by 2012.

This document aims to provide an outline on the minimum requirements which need to be in place for the effective management of IAP’s. It covers planning, implementation, monitoring and awareness.

2. Planning

Each Area within Mondi will compile their own plans at a Work Plan Unit (WPU) level using the following guiding principles:

  • Plans will be guided by factual, rational information and influenced by availability of resources;
  • Resources need to be maximised and utilised effectively and efficiently;
  • Maintenance of areas in an un-invaded state is as important as the clearing of invaded areas.

The following factors can influence prioritization within the planning process:

  • Previously worked areas are always a higher priority than new areas;
  • Areas in a maintenance phase should not be left to deteriorate and scheduled annually;
  • Areas to be removed from commercial plantation as a result of delineation shall be priority;
  • Management practicalities and availability of resources (i.e. transportation, equipment & people) ;
  • The importance of the sub-catchments in relation to other farms;
  • The extent of the invasion (area & density);
  • Species involved considering aggressive and emerging IAPs;
  • The risk of the invasion getting worse;
  • Importance of the area in terms of ecology and species diversity considering high conservation value criteria;
  • Progress is more obvious in dense stands and teams work more effectively;
  • Stakeholder complaints;
  • Areas managed with a primary objective of fire protection

The following plans will be compiled in each area:

  • Long Term Resource Plan (LTRP) – 5 year high level plan per WPU. Highlights priority areas and determines level of budget and people required. Updated annually.
  • Annual Plan of Operation (APO) –at a farm level. Uses LTRP as guide, records hectares to be treated & timing

2.1Long Term Resource Plan (LTRP)

The LTRP quantifies the level of work required to control IAP’s and how long it will take to reach an acceptable level of maintenance. By compiling this plan, it can be determined at a WPU level whether the current resources are sufficient to achieve the 2012 target. If it is determined that the current budget is not sufficient to reach a maintenance phase by 2012, scenario’s can be run to determine what is required and the implications if sufficient budget is not received.

The LTRP will be updated annually prior to the next years budget submissions (May). This will allow the forester to update the plan with the actual treatment undertaken and revisit the WPU clearing strategy and ensure that the budget submitted reflects the scale of the operations.

The LTRP outputs:

  • GIS based maps showing priority, units/ha, treatments per year and number of years to reach maintenance per Z-cmpt. The maps will be available on Mondi’s internal environmental website, pages for each area available on as well as in hard copy in the forester’s office.
  • Spreadsheet with calculations showing estimated number of years until maintenance at current budget levels (and other scenario’s if necessary) available from forester.

2.2Annual Plan of Operations (APO)

As the name suggests, APO’s are compiled annually. They are the first step towards achieving the 5 year strategy outlined in the LTRP. The APO uses the prioritization from the LTRP to determine which Z-cmpts require treatment during the year. It is essential that the APO is realistic and uses the budget and people available as well as the work load per Z-cmpt to determine how many hectares can be treated in any one month.

The forester needs to take cognizance of which months are available for burning (conservation and fire protection burning) as well as the growing seasons of some of the weeds which need focused attention (e.g. bramble, pompom).

Both these aspects will impact on the number of people which will be available to do “normal” conservation IAP control and consequently how many hectares can be treated.

The APO outputs:

  • Hectares to be treated per month at a farm level obtained from PMi
  • Planned Monthly expenditure per farm obtainable from Fortes.

3. Control methods

Mondi’s IAP Best Practice shall consider a number of criteria such as specific herbicides, treatments methods, species, approved and registered products, costs description, effective control or eradication, cost effectiveness of different treatments, the response of the treated plants - coppice, seedling control to ensure next operation is adequately planned.

Integrated control involves the use of mechanical, chemical and biological control. Many experts do not recommend the use of mechanical control for IAP’s as this can involve significant soil disturbance which will open up the area to other IAP pioneers. Many IAP’s also have coppicing and regrowth strategies which allow them to regenerate vigorously from root stock after disturbance. In exceptional circumstances and with the correct planning, manual methods can be considered.

The intention is to achieve maximum % mortality with the first treatment and as such the use of mechanical/manual methods without herbicide application will be discouraged. The use of non-selective herbicides as a foliar spray in non-commercial areas will be minimized through the application of Best Practice.

The following criteria influence the selection of a control method:

Species to be controlled / Coppicing ability will determine whether herbicides should be used or not. Thick or thin barked, woody or herbaceous species need different methods to ensure effective herbicide uptake.
Size of target plants / Small herbaceous IAP’s require different methods to mature woody trees.
Density of stand / Dense stands have cost and accessibility implications. A method which will be effective at reducing the density at a reasonable cost should be considered.
Accessibility of terrain / Steep areas are inherently unsafe to work in, control methods in these areas should not compromise safety further, e.g. no chainsaw work.
Environmental and personnel safety / Chances of trees killed standing causing damage at a later stage needs to be taken into consideration, e.g. large tree next to road/powerline/house or affect on aerial fire fighting.
Slash Management / Slash stacked too close to riparian zones pose a risk for stream crossings further downstream or they can cause erosion at bends along the riparian channel. Slash should be removed a sufficient distance from the river edge depending on catchment hydrology (rule of thumb = 20m).
Slash should be stacked in brush piles or brush lines with 5m gap to reduce fire risk.
Cost of application / Some manual methods are cheaper than chemical methods; however this is dependent on the density and age of the area to be treated.
Time of the year / Many species do not respond to herbicide treatment out of the growing season.
Stage of clearing / Areas at maintenance require less intense operations than initial areas.

3.1Chemical Control

Mondi will be prescribing Best Operating Practice (BOP’s) to IAP contractors to increase the efficacy of IAP control. The use of non-selective herbicides and herbicides found to be expensive or ineffective will not be included in the BOP’s. Detailed chemical control prescriptions have been compiled per species targeted using all available literature. The IAP herbicide treatment tables (Doc No. ETT-01 & ETT-02) containing control prescriptions are available in this file or electronically.


Biological control will be integrated into Mondi’s IAP Management. Biocontrol agent releases will be coordinated centrally by the environmental department in collaboration with Working for Water’s biocontrol experts and the Plant Protection Research Institute (PPRI).

The following species are regarded by the PPRI as being under total control with biocontrol agents. If any of these species are found on Mondi property, they will be inspected for indications that the biocontrol agent is present. If the biocontrol agent is not present, steps will be taken to introduce the agent and no other control will be done.

Species / Agent(s)
Silky Hakea (Hakea sericea) / Gummosis disease and other agents
Sesbania (Sesbania punicea) / 3x agents
Port Jackson Acacia (Acacia saligna) / Gall rust fungus
Harissia cactus (Harissia martini) / Mealy bug
Australian pest pear (Opuntia stricta) / Cochineal

A list of species with biocontrol agents is provided in the treatment tables (Doc No ETT-03). Negotiations will be undertaken with Working for Water to obtain agents and releases will be undertaken where required.

4. Implementation

4.1Dedicated teams

An aspect often overlooked in the planning process is the people factor. Money cannot be spent and follow-up cannot be done timeously if labour resources are not in place.

Dedicated conservation teams are an ideal training ground for developing contractors to develop their business skills before moving on to more intensive commercial operations.

Each WPU must have access to a dedicated conservation labour force to allow the forester to put their own plans into effect.

4.2Treatment methods

Chemical / Hack & Squirt / Cut stump / Stems should be cut as low as practical. Always make “clean flat” cut to plants to enhance the effect of herbicides. Herbicides are applied in water as recommended by the label.
Frill / Useful for thin barked species.
Make horizontal, downward angled cuts through the bark of target trees using an axe. Cuts should be connected around the entire circumference of the trunk, as close to the soil surface as possible.
Do not penetrate deeper than the sapwood. Apply herbicide as per label directly into every cut, taking care that product is not wasted on the bark.
Ring Bark with Herbicide / Used for thicker barked, difficult to kill species.
Using a hatchet/axe first make a bottom cut, followed by the top cut a hatchets length (0.5m) above this. The bark in-between is peeled away.
However, unlike ringbarking, the ring is required as low to the ground as possible. All cambium & phloem layers must be cleaned from this area. Herbicide must be applied to the cut surfaces within 15 minutes of the ring being cut, essential that the person ring barking also applies the herbicide.
Spot spray / Apply herbicide to active growing plants as a full cover leaf spray thoroughly wetting all foliage to the point of run off.
Manual / Ring bark / Using a hatchet/axe first make a bottom cut, followed by the top cut at least 30cm higher and remove all bark and cambium in a band around the stem at a height of about 50cm.
Strip bark / 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.

More detail on the methods is provided in Appendix A.

4.3 Timing of follow-up

Timing of follow-up operations is critical to ensure that work already done is not wasted. IAP’s have different growth rates depending on the surrounding vegetation and climate, particularly heat, rainfall and frost. Foresters should have a “Followup Inspection Schedule” which will assist them to determine when they need to plan a followup operation. The inspection schedule will prompt a forester to visit a previously treated area to determine if a followup is required yet or if it can be delayed for a few more months.

The table below provides a summary with some guidance:

Natural vegetation type / Recommended strategy / Reasoning / Recommended inspection period (months)
Frost free areas / Frost areas
Short grass / wetlands / Initial: Stump treatment
Follow-up: Spot spray of IAP’s when knee height
Burning could also be used on a bi-annual or tri-annual basis / IAP’s easily distinguished from natural veg, spot spray with selective herbicide / 3 / 6
Tall grass / Initial: Stump treatment
Follow-up: Leave for longer period, Allow IAP’s to flush until over head height, use stump treatments.
Burning could also be used on a bi-annual or tri-annual basis / Difficult to see IAP, allowing them to “grow out” above natural vegetation means operators can see them. Stump treatment preferred. This strategy also allows more of the IAP’s seeds to germinate between treatments ultimately reducing the number of followup operations required. / 6 / 6
Disturbed site with minimal natural vegetation / Initial: Stump treatment
Follow-up: Spot spray of IAP’s when knee height
Burning could also be used on a bi-annual or tri-annual basis / Predominantly IAP’s, operator does not need to distinguish between natural veg and IAP’s / 3 / 6
Dense pockets of infestations within Indigenous forest/thicket / Initial: Kill standing (frill or ring bark).
Follow-up: Spot spray / stump treat all IAP seedling growth / Felling will create disturbance of the canopy. Kill standing will maintain the shade canopy and allow indigenous pioneers to colonize area. / 3 / 6
Fire breaks / Post burn control required. / Species growth retarded by fire but species not killed therefore chemical operation required post burn. / 3 / 6

NB: the above table is meant as a guide only and is the personal opinion of the author. Different circumstances could alter these recommendations.


Monitoring is required to determine firstly, whether the WPU’s are achieving their plans and therefore the strategy outlined in the LTRP and secondly, the effectiveness of the control efforts at increasing the areas at maintenance. It is essential that a forester knows at any one time whether they are on track to achieve their targets or not.

5.1 Monthly against APO

Operations will monitor their IAP work (i.e. R’s spent and ha’s cleared) on a monthly basis against their APO. The monitoring needs to consider the R/ha as well as units/ha costs. A spreadsheet based tool has been developed to assist with this.

Operational efficacy

Effectiveness of infield operations will be assessed regularly and discussed with the foresters with a focus on continual improvement. This will include enforcing the species prescriptions.

It is essential that operations undertaken are done efficiently within accepted production norms. In many cases there are no norms for the work to be undertaken, particularly in inaccessible areas.

Mondi will work towards drawing up a set of production norms for the different scenarios under which work may take place. The foresters and contractors will be included in the process and will receive training on this.

5.3 Annual IAP assessments

IAP assessments will be done annually to assess the level of infestation in the non-commercial areas and progress towards achieving maintenance levels. Each Z-cmpt will be assessed for the presence of IAP and the overall % spread of all IAP will be estimated by the assessor. The following 3 categories will be monitored:

% Spread / Definition / Description
0-5% / Maintenance / Z-cmpts that have less that 5% weed spread are regarded as being in a maintenance phase. Maintenance means a low intensity, 0.5- 1 unit/ha operation or a burn is sufficient to control IAP present.
5-25% / Under control / Z-cmpts which are on the follow-up schedule. They have low weed spread but need a few more treatments before they can be regarded as being at maintenance.
>25% / Transitional weed / Z-cmpts that have a high weed spread and will need at least 3 years to reach a controlled phase.

6.Awareness & training

Awareness and training activities will be undertaken at all levels from laborers, supervisors, contractors and foresters.

6.1 Training

A training matrix will be compiled which outlines what training should be done at the different levels and will cover aspects such as:

Forester / Contractor / Supervisor / Worker
IAP identification / X / X / AR / AR
Herbicide awareness / X / X
PCO / LPCO / X / X
Control methods / X / X / AR / AR
Mixing of herbicide / X / X / AR / AR
Herbicide application / X / AR / AR
Calibration / AR / AR / AR
Planning / X / X
Productivity norms / X / X / X

*AR – annual refresher required

6.2 Awareness

Awareness of IAP’s focusing on “What are they”; “What do they look like”; “How to treat them” will be undertaken. One page BOP’s will be compiled per species which outline the time of treatment and most effective treatment method for that particular species. Credit card sized ID cards will be produced per species which will assist with identification and outline the control prescriptions.