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Where and how are herbicides sprayed?

Category: Herbicide Operations

Herbicides, including glyphosate-based herbicides, are used in areas of the forest using specialized aircraft. This is done either before new seedlings are planted, or 2-5 years after new seedlings become established. Areas of the forest are only ever sprayed once or twice in a 40-80 year growing cycle.

Glyphosate-based herbicide being applied by air to a planted forest site. (Photo: Doug Pitt)

Where conifer production is desired, herbicides, including glyphosate-based herbicides, are applied under two different strategies, either prior to planting (chemical site preparation) or after seedlings are established (tending or release). Owing to the efficiency, effectiveness and low-impact-nature of the technique, aerial application using either fixed-wing or rotary-wing aircraft, is the most common method of distributing herbicides to target sites, accounting for more than 88% of all forestry applications in Canada over the last decade (http://nfdp.ccfm.org/). Applications via tractor-mounted sprayers and personnel-carried backpack-sprayers account for the remaining 12%. Typically, herbicides are applied within the first five years post-harvest, and any given site receives one or at most two treatments during the life of the stand, typically 40 to 80 years in Canada.