Oplopanax horridus

Oplopanax horridus occurs from southern Oregon north through western Canada into Alaska. It also occurs disjunctly in Michigan and Ontario. It is relatively more abundant in the northern portion of its range, is considered a wetland habitat indicator, and grows in old growth riparian habitats. Although this species seems able to adapt to disturbance to a certain extent, it is threatened by high intensity fires, habitat loss, and over-grazing. This species is also potentially threatened by wild-collection for medicinal use. Interest in Oplopanax horridus for this purpose is reportedly increasing and it is closely related to other highly traded species, for which it has been used as a substitute.

Oplopanax horridus is concentrated in the Pacific Northwest, western Canada, and Alaska. It also occurs disjunctly in Michigan and Ontario, where it is considered rare.

Ecological threats to this species include habitat loss and fire. Habitat loss due to logging will threaten native populations, since this plant is very light sensitive (pers. comm. A. Bentley, October 2000, Alaback 1980). High intensity fires can devastate this species, however such fires may not be very frequent in its range, particularly to the north. Fire has been shown to kill populations that may take decades to regenerate by seed (Alaback 1980, Vance et al. in press). This species is also vulnerable to over-browsing by elk in limited areas.

Another potential threat is that cuttings of Oplopanax horridus collected from the wild appear to be gaining in popularity from the perspective of experienced herbalists (pers. comm. R. Klein, October 2000; pers. comm. A. Bentley, October 2000). Some experts in the medicinal plant industry have suggested that trade is medium to large and demand has increased over the past ten years (Robbins 1999). Specifically, O. horridus is gaining popularity for use as a supplement for controlling diabetes (pers. comm. A. Bentley, October 2000, Vance et al. in press). This species is also sold as "industrial grade Panax ginseng" (Vance et al. in press). Since it is possible to cultivate this plant and seeds and plants are commercially available (Vance et al. in press), it is unclear whether cultivation is relieving pressure on wild plants. Therefore, amounts of cultivated versus wild-harvested material in commercial trade should be investigated. This plant is also commercially available as an ornamental. Vance et al. (in press) suggested that utilizing specific harvesting techniques for sustainable use could alleviate long-term threats to wild populations. Therefore, potential threats caused by wild collecting can be mediated by individual collectors (see Vance et al. in press).