Herbicides are used in Nova Scotia’s forests to encourage softwood trees to grow in clearcuts by killing or retarding the growth of hardwood trees and shrubs, some softwood tree species and other plants. On average in recent years, nearly 4,500 hectares per year of Nova Scotia’s clearcut forest have been aerially sprayed with the herbicide VisionMax, the active ingredient of which is glyphosate.
Herbicides are often used to help create intensively-managed softwood-dominated plantations and forests following clearcutting. Clearcutting and intensive management for a few selected species convert Nova Scotia’s natural mixed-species Acadian forest into a simplified agriculture-type ecosystem with little biodiversity value. As such, the use of herbicides is a symptom of regressive forestry practices – the clearcut, plant, spray, repeat model. Spraying Nova Scotia’s forests with herbicides has no place in science-based forest management.
The Nova Scotia Department of Natural Resources (NSDNR) contends that herbicides are necessary to ensure successful regeneration of trees in clearcuts. However, research conducted by the Ecology Action Centre using data from NSDNR demonstrates that if all commercial tree species (rather than the few softwood species included by NSDNR) are counted towards successful regeneration, then herbicides have little positive effect on regeneration.
Therefore, given that
(a) herbicides tend to reduce the biodiversity value of our forests,
(b) glyphosate is classified as a probable carcinogen by the World Health Organization,
(c) herbicides are closely tied with clearcutting and often plantations, and as such are a symptom of poor forestry practices,
(d) VisionMax (the herbicide most commonly used on Nova Scotia’s forests) harms biodiversity, including amphibians,
(d) herbicides are not required to ensure adequate growth of tree species following clearcutting, and
(e) Nova Scotians have expressed clearly through the Natural Resources Strategy process that they want to see clearcutting reduced,
the Ecology Action Centre asserts that herbicides have no place as a forestry or cosmetic landscaping tool in Nova Scotia. The Ecology Action Centre strongly recommends that
(1) the Province should not fund herbicide applications on any forestland (private or public),
(2) the Province should ban the use of herbicides on Crown land, and
(3) the Province should provide landowners and forestry companies with state-of-the-art guidance and expertise on science-based harvesting and silviculture methods that eliminate the use of herbicides.
Although long-term trends in forest herbicide use in Nova Scotia have not been released publicly, we know that in recent years nearly 4,500 hectares of Nova Scotia’s clear-cut forest have been aerially sprayed with herbicide each year on average. VisionMax is the brand-name herbicide of choice in Nova Scotia and is produced by the Monsanto Corporation. According to its label, it is effective at controlling (killing or supressing) a range of plants, including alders, birches, cedar, cherries, hemlock, maples, pines, poplars, rhododendron, meadowsweet, heath species, sweet fern, raspberry, withrod and willows. Conifer species (pine, hemlock and cedar) can be killed or supressed if sprayed when they are actively growing. Planted species are generally put through a special dormancy-inducing treatment prior to being planted and sprayed.
The active ingredient of VisionMax is glyphosate, making up approximately 40% of VisionMax. The rest of VisionMax is water and a cocktail of numerous chemical ingredients (known as adjuvants) that are NOT listed on the label. Adjuvants include compounds known as surfactants, chemicals that help glyphosate enter a plant’s vascular system in order to kill it. Some surfactants have been shown to be more toxic than glyphosate itself.
Monsanto, the manufacturer, is permitted to keep the list of adjuvants off of the label because they’re considered to be “confidential business information”. So no one really knows all the chemicals that are in VisionMax or what their effects on people and wildlife may be.
Glyphosate-based herbicides are classified as moderately to highly toxic to one of our forest’s ‘keystone’ groups of organisms: amphibians. The expected environmental concentration of herbicides following forestry applications is at or above the toxicity level for some amphibians. Researchers have noted that the toxicity of herbicides such as VisionMax to amphibians may be due to the chemical polyethoxylated tallow amine (POEA), one of the surfactants used in Monsanto’s herbicides. As well, the toxicity of glyphosate is increased in waters that are acidic, such as many watercourse systems in Nova Scotia.
Glyphosate also kills vegetation that creates the shade and moisture that many forest amphibians need to survive. While there are narrow (20-metre) buffers between clearcuts and larger watercourses, there are no restrictions on clearcutting and applying herbicide to vernal pools, which are critical habitats for Nova Scotia’s forest amphibians. The label for VisionMax warns that people must not enter a sprayed area for 12 hours after spraying. This is little help for the frogs, salamanders and other wildlife who live in sprayed areas. And of course, the dozens and dozens of “weeds” killed by VisionMax are really plants that produce food for wildlife and play their own role in our forest’s complex ecosystems. Finally, glyphosate is an antibiotic, and known to influence the microbial flora in animals, thereby impacting immune systems in animals.
The World Health Organization recently labeled glyphosate as “probably carcinogenic to humans.” In reaching this decision, the WHO noted some evidence of a “positive association between glyphosate exposure and risk of non-Hodgkin lymphoma….” With respect to diet, the WHO concluded that glyphosate is unlikely to pose a carcinogenic risk to humans from exposure through diet alone.
In 2010, Nova Scotia’s Framework for Forestry stated that “public funds will not be directed to herbicide spraying for forestry.” In 2011, the Natural Resources Strategy similarly stated that “… public support will no longer be extended to the use of herbicides.” This means that taxpayer dollars would no longer be used to subsidize forestry herbicide spraying.
But now is the Nova Scotia government having a change of heart? The Department’s recent 2016 “Progress Report” announced that, along with killing the commitment to reduce clearcutting to no more than 50% of all forest harvesting, “as we move forward … we will continue to assess the effectiveness of various forestry practices, including herbicide use.” Not only that, but in March 2016, the government also dropped Forest Stewardship Council (FSC) forest certification for Crown lands in western Nova Scotia only a year after committing publicly to expanding the FSC program to all Crown Lands. FSC certification is considered the “gold standard” for environmentally and socially responsible forestry management and requires that, among other things, forest managers reduce their reliance on herbicides and pesticides. Now that the government has abandoned its commitments to reduce clearcutting and other harmful practices it appears they may be preparing to once again make taxpayers pay for a herbicide spraying program that the public does not support.
1 Charbonneau, D and J Simpson. 2010. Forest Herbicides as a Vegetation Management Tool: Perspectives on the future of forest management in Nova Scotia. Ecology Action Centre: Halifax.
2 Govindarajulu, P. P. 2008. Literature review of impacts of glyphosate herbicide on amphibians: What risks can the silvicultural use of this herbicide pose for amphibians in BC? Wildlife Report No R-28: BC Ministry of Environment.
3 Schrodl, W. et al. 2014. Possible effects of glyphosate on Mucorales abundance in the rumen of dairy cows in Germany. Current Microbiology: 69(6): 817-23.
4 International Agency for Research on Cancer, World Health Organization, Monograph Vol 112 (Glyphosate).
5 Joint FAO/WHO Meeting on Pesticide Residues: Summary Report, May 16, 2016.