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According to a 2006 article published in The American Midland Naturalist, wild-harvested goldenseal (Hydrastis canadensis) populations may regenerate at different rates according to their locations and the seasons during which they were harvested.1 The authors of the article conducted a 4-year study in the Wayne National Forest in Ohio, monitoring the re-growth of a goldenseal population wild-harvested during the fall of 2001. These data were compared to previous studies that quantified the re-growth of goldenseal populations wild-harvested during the fall in West Virginia2 or experimentally harvested during mid-summer.3
The authors randomly selected and measured 75 goldenseal ramets (individual members of a cloned strain) from the Ohio population twice, over 2-year intervals, and compared these measurements to the previously published data concerning goldenseal re-growth in West Virginia.1 The researchers found that ramet densities increased 210% in the fall harvested Ohio population, but declined slightly in the fall-harvested population from West Virginia.* There was also a greater proportion of reproductive plants in the Ohio population. Meanwhile, mean ramet leaf area was similar for fall-harvested populations from both states, whereas the ramet leaf area was much smaller in the summer-harvested populations.† The study therefore suggests that the seasonal timing of harvest may impact the rate at which goldenseal populations regenerate (although expert peer reviewers of this HerbalEGram article have emphasized that harvest time, stage of plant growth, and the amount of rainfall immediately preceding the harvest does strongly impact regeneration).
According to the authors of the article, “Collectively, studies from OH and WV suggest that fall-harvested goldenseal populations may recover (in terms of leaf size) at faster rates than those harvested during mid-summer.” This would indicate that fall harvest of goldenseal root is more conducive to sustainable wildharvest. Patricia De Angelis, PhD, a botanist in the division of scientific authority at the US Fish and Wildlife Service (FWS), added that “from a chemical standpoint, fall is the best time to harvest because the alkaloid content increases as the plant nears dormancy” (e-mail, March 20, 2007). Michael C. Tims wrote about this topic in his 2006 dissertation (https://drum.umd.edu/dspace/bitstream/1903/4052/1/umi-umd-3762.pdf), submitted to the University of Maryland: “Of note, Renaud and Strauss…compared seasonal variations in berberine and hydrastine content of wild goldenseal root collected from north- and south-facing collection sites in Rutland, OH during April, June, September, and November...The authors also noted that the total alkaloid content was highest at both sites in November, at which point Hydrastis begins winter dormancy, and reallocation of alkaloid to the root may have occurred.”4
The authors of the present article note that the differences in goldenseal population re-growth found in their study could be associated with a number of factors in addition to wild-harvesting, including variability in harvesting methods, deer browsing, and differences in environmental attributes, among others.1 They conclude that further study is warranted to determine sustainable harvest rates for goldenseal under different intervals and conditions, particularly since goldenseal has been the subject of conservation efforts.
The authors further note that such studies are warranted since goldenseal’s ecological lifehistory “suggest it is sensitive to over-harvest.” A reviewer of this article for HerbalEGram, Edward Fletcher of Strategic Sourcing Inc. (Banner Elk, NC), pointed out that this does not mean that goldenseal has difficulty in regenerating. “Under the proper conditions, harvested considering the season and weather conditions, goldenseal rootlets or broken fiber roots have a high survival rate and regenerate at a high percentage; they are just slow, i.e., as in 5-7 years to maturity” (e-mail, March 23, 2007).
According to the Medicinal Plant Working Group Fact Sheet for goldenseal (currently under production by the Plant Conservation Alliance), goldenseal is one of the oldest documented medicinal plants of North American origin and is among the 20 leading herbal materials within the worldwide market.5 Goldenseal is listed as threatened in Canada and is listed as endangered, threatened, vulnerable, or of special concern in several areas of the United States (Connecticut, Georgia, Maryland, Massachusetts, Michigan, Minnesota, New Jersey, New York, North Carolina and Vermont). The plant has been included in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) since 1997, and it is listed as “At Risk” by United Plant Savers (UpS), a nonprofit dedicated to preserving native medicinal plants.
The Tonnage Survey of North American Wild Harvested Plants, 2004-2005, recently released by the American Herbal Products Association, includes a section devoted entirely to goldenseal cultivation and harvesting.6 The latest figures show that combined cultivated and wild-harvested goldenseal root and rhizome that entered the market as dried material rose to 42 and 41 tons for 2004 and 2005, respectively, from 21 tons in 2003. The harvest of wild goldenseal root that entered the market as fresh material dropped to nearly insignificant levels compared to previous years. The survey also included a chart showing that the majority of goldenseal root is still wild harvested-41% of dried goldenseal roots were cultivated and 59% were wild harvested in 2005.
-Courtney Cavaliere
References
1. Albrecht MA, McCarthy BC. Comparative analysis of goldenseal (Hydrastis canadensis L.) population re-growth following human harvest: implications for conservation. Am Midl Nat. 2006;156:229-236.
2. Van der Voort, ME, B. Bailey, DE Samuel, JB McGraw. Recovery of populations of goldenseal (Hydrastis canadensis L.) and American ginseng (Panax quinquefolius L.) following harvest. Am Midl Nat. 2003;149:282-292.
3. Sanders S and JB McGraw. Harvest recovery of goldenseal, Hydrastis canadensis L. Am Midl Nat. 2005;153:87-94.
4. Tims MC. The chemical ecology of Hydrastic canadensis L. (Ranunculaceae): effects of root isoquinoline alkaloids on the Hydrastis endophyte, Fusarium oxysporum [dissertation]. College Park, MD: University of Maryland; 2006.
5. Lonner, J. 2007. Plant Conservation Alliance-Medicinal Plant Working Group Fact Sheet on Goldenseal; in press.
6. American Herbal Products Association. Tonnage Survey of Select North American Wild-Harvested Plants, 2004-2005. Silver Spring, MD: American Herbal Products Association; 2007.
* The authors of the article claim to have adopted the sampling scheme used in the previously published study from West Virginia (Van der Voort et al., 2003) to census population re-growth. They compared their own Ohio data to the previously published data from Table 2 in Van der Voort et al’s 2003 study. The W. Virginia population was surveyed annually, whereas the Ohio population was sampled the second and fourth growing season following harvest.
† The authors compared their fall-harvested Ohio results and the W. Virginia data of Van der Voort et al. to a previously published study (Sanders and McGraw, 2005) concerning summer-harvested goldenseal. The authors do not mention the location of the summer-harvested populations studied by Sanders and McGraw.
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