Glyphosate has long been a cornerstone of vegetative management in commercial forestry. Its effectiveness and affordability have made it a preferred herbicide for controlling competing vegetation and invasive species. However, growing environmental and health concerns, stricter regulatory scrutiny and shifting market demands – both locally and globally – are urging forestry stakeholders to seek viable alternatives. In South Africa, where commercial forestry is essential to rural economies and national export value, moving toward sustainable and legally compliant alternatives is becoming increasingly important.

Why the Shift Away from Glyphosate?

Internationally, glyphosate faces intense scrutiny over its potential environmental and human health risks. In South Africa, while still permitted, glyphosate and other agrochemicals are being affected by increasing legislative constraints, such as the Substances of Concern Register and the Restricted Remedies List maintained by the Department of Agriculture, Land Reform and Rural Development (DALRRD). Furthermore, forest certification schemes such as the Forest Stewardship Council® (FSC®) are encouraging reduced reliance on high-risk chemicals – influencing both operational and market strategies.

Chemical Alternatives to Glyphosate

While no single herbicide replicates glyphosate’s broad-spectrum performance, several targeted herbicides can be combined in an Integrated Vegetative Management (IVM) approach. Below are viable chemical options increasingly considered in South African forestry:

  Use Pros Cons
Triclopyr Broadleaf and woody vegetation.

Effective against coppicing and scrub regrowth.

 

 Costlier than glyphosate; environmental persistence.
Imazapyr Broad-spectrum, including woody species.

Long residual action – useful in pre-planting site preparation.

 

 High soil activity may affect non-target plants.

Clethodim

 

 Post-emergent control of grass species.

Selective, especially useful when establishing broadleaf plantations.

 

Narrow spectrum, typically used in targeted applications.

 

Clopyralid

 

 Control of broadleaf species, particularly effective against thistles and composite weeds.

Safe for use around grasses; compatible in mixtures.

 

 Persistent in plant residues; potential for drift.

Flumioxazin

 

 Pre-emergent herbicide for broadleaf and some grass species.

Long residual activity; effective in seedbank control.

 

 Limited post-emergent effect.

Fluroxypyr Meptyl Ester

 

Control of woody and broadleaf invasive species.

 

 Rapid foliar uptake; effective in aerial or targeted sprays. Requires careful handling to prevent drift.

Metsulfuron-Methyl

 

Broadleaf control in forestry and non-crop areas.

 

 Very low application rate; cost-effective.

Soil mobility; rotation restrictions for sensitive crops.

 

Pelargonic Acid (Nonanoic Acid)

 

 Natural contact herbicide for green vegetative cover. Quick action; organic-compliant. No residual control, therefore suited for spot treatments.

NOTE: Before using any agrochemical product, always read the label and ensure compliance with the Fertilizers, Farm Feeds, Agricultural Remedies and Stock Remedies Act (Act 36 of 1947). Please note that NONE of these products are registered for firebreaks.

For guidance on registered products approved for use in South African forestry, consult the TIPWG Approved Pesticide List (APL) at APL – Tipwg.

Biological and Organic Approaches

  1. Mulching and Ground Covers: Use of bark, straw, or matting to suppress vegetative growth. Best suited to nurseries or intensive silvicultural plots.
  2. Allelopathic Plants: Use of plant species with natural inhibitory compounds (e.g. Tagetes) to reduce unwanted vegetative cover in borders or buffer zones.
  3. Bioherbicides: Ongoing research into pathogens and microbes targeting specific invasive species is promising but currently limited in availability and scalability.Mechanical and Manual Methods
    Brush cutting, hoeing and slashing remain effective, especially in early rotations or targeted invasive management.
  • Challenges: High labour cost, safety risks and potential damage to seedlings.
  • Future advances: Mechanised tools with selective cutting ability offer better operational safety and efficiency in rugged terrain.

Integrated Vegetative Management (IVM): A Sustainable Path Forward
The most effective strategy is not replacing glyphosate with one chemical but replacing a dependency model with an integrated system. IVM combines:

  • Site-specific planning based on topography, soil type and species dynamics.
  • Rotation of herbicide modes of action to prevent resistance.
  • Mechanical control where feasible to reduce chemical inputs.
  • Monitoring and adaptive management using GIS, drone surveys and stakeholder feedback.

Regulatory and Certification Considerations

  • South African law increasingly requires compliance with updated risk assessments, product registration statuses and safe-use protocols.
  • Chemical users must monitor DALRRD’s Substances of Concern Register and Restricted Remedies List to ensure legal compliance.
  • FSC® and Programme for the Endorsement of Forest Certification™ (PEFC™) certified operations should aim for reduced chemical use, documentation of alternatives explored and a justifiable rationale for any remaining use of restricted substances.

Conclusion

Glyphosate’s role in forestry is becoming more complex, not just due to market or environmental concerns, but because of regulatory tightening in South Africa and abroad. While no silver bullet exists, a well-planned combination of chemical, mechanical and biological methods – aligned with IVM principles – offers a pathway forward that is responsible, cost-effective and sustainable. For South African forestry to remain resilient and competitive, it must embrace innovation while staying aligned with environmental stewardship and legal best practice.