There is renewed debate regarding the use of herbicides to treat regenerated forests in light of a recent report from the International Agency for Research on Cancer (IARC) on the carcinogenic effects of a very common herbicide called glyphosate. People have questions and some of the answers they have received from critics calling for the outright ban of herbicides in forest management have unfortunately avoided a full recounting of the facts leaving concerned citizens scratching their heads as to what to believe. So this article will try to provide a little background and balance to the debate.
The IARC opinion is based on a review of existing studies and categorizes glyphosate in the same probable cancer causing category that includes coffee, cell phones, aloe vera extract and pickled vegetables, this according to a recent article in the noted journal Nature. IARC admits that there is limited evidence for a link to cancer in humans. IARC’s work, in general, is not without merit but as some scientists have commented, including Oliver Jones an analytical chemist at RMIT University in Melbourne, that the IARC evaluations are usually very good, but the evidence cited in this case appears a bit thin.
So why do we use glyphosate in our forests? The rationale is simple enough; when softwood forests regenerate naturally or through silviculture renewal, meaning planting, these trees are in competition for the sun and nutrients by less desirable woody shrubs and trees. Where necessary, applying an herbicide like glyphosate will supress the unwanted trees and permit the softwood to grow unimpeded. It’s basically a race between the trees we intend to grow and those that are less valuable. It is not used everywhere only in areas where softwoods are the preferred species and in fact a significant percentage of the suppressed hardwood does sprout back creating a good food source for wildlife in particular deer.
Most people are unfamiliar with the name but it can be found in many homes as the active ingredient in the residential herbicide Roundup. When used as directed it’s an effective treatment for undesirable broadleaf plants to achieve mainly a nice looking lawn or walkway free of unsightly weeds.
For our forest industry it has nothing to do with esthetics but everything to do with protecting the public’s investment in a sustainably managed forest. Glyphosate use in forestry is poorly understood by the public so here are a few facts regarding its use and the impact on the environment and human health.
1) The herbicide glyphosate is one of the most widely used herbicides in the world and has been approved for safe use for over 40 years.
2) Herbicide use in forest operations is the most cost effective way to protect public forest investments, your investment, from lost growth.
3) Application of herbicides are strictly regulated by government and precautions are taken to mitigate exposure to people and non-target areas like rivers, streams and lakes.
4) According to Health Canada and numerous government agency studies in Germany, Australia, and the U.S. Environmental Protection Agency (EPA), regulated use of glyphosate is not quantifiably linked in any way to increased risk of cancer or any other human health issues.
5) Contrary to certain claims and as identified in the 2012-13 NB DNR annual report, herbicide use is not extensive on NB crown forests. It is applied to less than 0.5% of the 3 million hectares of crown forest.
So the facts behind glyphosate herbicide support its safe and effective use. Used responsibly it’s a good tool for improving our forest productivity and is compatible with broader management objectives that include non-timber as well as timber requirements. It’s important to know all the facts before drawing conclusions on this issue.
For more information visit Herbicide use.