Interestingly, climate change threatens the range of Canada Yews because it affects snow cover. Snow cover prevents Canada Yew from being overgrazed in the winter months. Quite simply, if there is no snow cover then Canada Yew will likely be overgrazed.
Canada Yews are one of a few plants that can survive the deep shade of old-growth hemlock forests. Removal of hemlocks destroys the Canada Yew beneath it. Truly, the removal of any over-story plant where Canada Yew is found will lead to extirpation.
Several indigenous peoples used parts of the Canada Yew for medicinal purposes. The Ojibwa used leaf decoctions to treat arthritis while the Menomonee steamed the needles and used them in herbal baths to ease rheumatism, numbness, and paralysis. The Potawatomi used a leaf decoction as a diuretic and a treatment for gonorrhea. The Algonquin boiled the needles with wild cherry to treat rheumatism and drank tea after childbirth to ‘bring out clots’ and alleviate pain.
The plant is typically monoecious, but, has exhibited dioecy. The size of the plant appears to influence sex expression. Small plants tend to be more male, but in the event it is monoecious there are more female strobili than male. Larger yews tend to be monoecious, but there are more male strobili than females on the plant.
In the 1960s, the United States Department of Agriculture and the National Cancer Institute began testing Canada Yew for cancer-fighting chemicals. It was discovered that Paclitaxel, an active anti-cancer chemical, was present in the bark of Pacific Yew (Taxus brevifolia). Unfortunately, the demand for paclitaxel was greater than the supply of the plant and too difficult to produce synthetically. All yew species were then studied, leading to the discovery that Canada Yew also contained paclitaxel as well as two other chemicals that could be used to synthesize paclitaxel. There is a theory that with such high levels of taxanes in Canada Yew, the species has the potential to become one of the most valuable natural sources for the pharmaceutical industry.’