Industrial forestry operations commonly utilize pesticide applications (primarily, if not exclusively, herbicide applications that hinder growth of noxious and invasive weeds like Himalayan blackberry) to ensure the success of newly replanted forests.
Even though data indicates forestry pesticide use only accounts for four percent of annual pesticide use in Oregon, this practice has attracted scrutiny from those concerned about the impacts to water quality. As a result, several studies have evaluated what, if any, impact forestry pesticide use has on water quality.
The conclusion from a growing body of research – all of which pre-dates dramatic expansion of herbicide buffers on forest streams in 2023 – is that this practice is not a source for water quality concerns:
- According to the 2022 Eugene Water and Electric Board’s recent water quality monitoring of the McKenzie watershed, their water “meets or exceeds all state and federal drinking water health standards, and that EWEB has once again been listed as an “Outstanding Performer” by Oregon Health Authority (OHA).” This is despite private industrial forestland accounting for the greatest single land use in the McKenzie watershed (approximately 37 percent), and despite extensive testing for hundreds of potential contaminants, they found no evidence of contamination from forestry.
- In 2012 the U.S. Geological Survey in coordination with EWEB published a report on pesticide detection in the McKenzie River Basin using 117 samples taken over the course of eight years. Despite screening for 175 compounds, the report concluded “forestry compounds were rarely detectable in the McKenzie River, even though forest land predominates in the basin … [and] forestry pesticide use is not considered a likely threat to drinking water quality at the present time.”
- After a decade of water quality monitoring through the Pesticide Stewardship Partnership (a joint effort of the Oregon Departments of Environmental Quality, Agriculture, Forestry and the Oregon Health Authority) pesticides were only detected in, at most, eight percent of samples taken from forested areas, and the highest level of detections were seven times lower than safety benchmarks for aquatic life. Both the Yamhill and South Umpqua monitoring efforts concluded applications used in forestry lie within the low concern category and pose a low threat to aquatic life.
- In 2000, the Oregon Department of Forestry published a report that evaluated the effectiveness of existing forest practice rules at protecting streams from contamination during aerial applications of forest pesticides. The report concluded “forest practice rules are effective at protecting water quality… [and] no changes are recommended to the forest practice rules.”