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Aren’t alternative approaches less risky than herbicides?

Category: Vegetation Management

Not necessarily. There are risks associated with every forest activity or operation; mechanical cutting exposes workers to known carcinogens through exhaust fumes; heavy equipment results in significant carbon emission and soil compaction; fire can be unpredictable and difficult to contain.

It is important to note that all vegetation management options carry some inherent degree of risk either to environmental or human health. The actual risks for non-herbicide options are certainly less well-studied and defined than those associated with herbicide use, a fact which is not necessarily a good thing. Risks of potentially deleterious effects of alternatives are technique specific. For example, mechanical site preparation with large machinery carries risks associated with harm to wildlife, soil compaction, increased erosion and excessive burning of fossil fuels (Newton 2006). Manual clearing with brush saws involves unequivocal risk to workers associated with repetitive direct exposure to proven carcinogens such as benzene in exhaust fumes, as well as demonstrable risks for stress- and strain-type injuries (Dubeau et al. 2003). Prescribed fire also carries risks associated with the safety of workers and the possibility that the fire will escape.

With herbicide use, risks may be associated with the potential for direct or indirect effects on wildlife species or to humans that may be inadvertently exposed to herbicide residues. However, such risks are significantly mitigated by the extensive scientific research that is invoked to enhance our understanding and define biological effects thresholds, resulting in the operational restrictions and practices that are put into place to reduce the probability that actual exposures will exceed such thresholds (e.g., buffer zones, signage, use of minimum effective rates, advanced application technologies to optimize targeting and reduce off-target drift potential) (Best Practices).

There are important differences between scientifically quantifiable risk or probability of occurrence, and the willingness of an individual or particular segment of society to tolerate those risks and probabilities. Risk tolerance varies dramatically from one segment of society to another and often directly reflects familiarity and knowledge (Wagner et al. 1998).



Dubeau, D., DeBel, L.G., Imbeau, D. 2003. Integrated study of brushsaw operators in Quebec. Research note. Tabled at XII World Forestry Conference by Ministere des Ressources, de la Faune et des Parcs du Quebec, Quebec, QC. Accessed Jan. 31, 2005 at http://www.mrn.gouv.qc.ca/english/publications/for... /Dubeau-A.pdf.

Newton, M. 2006. Taking charge in forest vegetation management. Canadian Journal of Forest Research 36: 2357–2363.

Wagner, R.G., Flynn, J., Gregory, R., Mertz, C.K., Slovic, P. 1998. Acceptable practices in Ontario’s forests: Differences between the public and forestry professionals. New Forests 16:139-154.