Harvest of ginseng has a long history in eastern North America, and there is no doubt that unregulated harvest can harm wild populations. Here is what scientific studies have shown about the direct and indirect effects of harvest:
• Large plants are most coveted by harvesters because they provide the greatest monetary return per unit digging effort.The problem: The largest plants in the population contribute the most to population growth.1,2,3,4,5 Thus, harvesters are removing what are arguably the most ‘ important’ individuals for a population’s long-term viability.
• Harvesters can reduce impacts of removing large plants by taking only plants with viable seeds.3
This is one component of a stewardship approach to harvesting, whereby diggers sacrifice some current profit – leaving behind non-reproductive individuals – in order to ensure a profit in the future in the form of a sustained or growing population.
• Harvesters can further reduce their impacts by on-site planting of the seeds from harvested plants in an optimal manner.
A study showed that optimal planting depth is about 1 inch deep.6 It has been speculated (though not shown with experiments) that each seed should be planted separately near the parent plant (because if the parent succeeded in that environment, the offspring would likely succeed too), but not too near (to avoid disease transmission to the young seedling) – perhaps 2 – 4 ft away, with some consideration given to reducing visibility/access to both deer and harvesters.
• Unethical harvest is common and occurs in three ways:7
(1) Harvest occurs frequently in places where it is not legal. National parks, nature preserves, state parks, and state forests appear to be particularly vulnerable, yet harvest is illegal in most such settings.7 Harvesters must resist the urge to dig plants where it is illegal. Not only is this behavior criminal, and subject to prosecution, it prevents our nature preserves and parks from acting as intended... as society's "Noah's Arks." Like marine reserves in the ocean (where fishing is prohibited), parks and preserves on land act as genetic reservoirs that can be sources for later re-colonization elsewhere.
(3) Plants are harvested that are too small. Most state regulations stipulate that plants must be 3-pronged prior to harvesting, yet many are taken before that size threshold is reached.7 This means that those plants have likely not replaced themselves before being removed from the population.
• Even ‘compliant’ harvest – in which diggers follow the letter of the law – is not sustainable in the long-term.
However, harvesters acting in a stewardship manner, can not only sustain populations, but grow them.3
• Harvest that reduces population sizes has indirect negative effects, including:(1) Reduced ‘mating success’ (lower seed production)8
(2) Lower genetic diversity9
(3) Lower fitness due to inbreeding10
(4) Selection against large sized plants11
(5) Decreased root sizes, as evidenced by shrinkage over the past two centuries12
• The effects of harvest are not necessarily the same when other factors are considered.
For example –
-Deer browsing may ‘hide’ plants from harvesters4
-Effects of climate change on viability may be worse when harvest is also present13
• Good harvesting practices are outlined by the American Herbal Products Association, with links to downloadable brochures specific to each state that allows harvesting.
It is relatively simple to practice good harvest behavior, which doesn't negatively impact ginseng population growth.
A healthy four-prong ginseng plant
Ethical and Sustainable Harvest How-To:
1) Familiarize yourself with Ginseng Harvest Laws in your state (see below).
2) Always ask permission, or acquire the proper permits, to harvest if it is not on your property.
3) Harvest only 25% of all mature plants in a population (3 to 4 prong plants) that have red fruit.
4) Plant the seeds near the host plant, make sure the seeds are about an inch deep in the soil.
Overview of Harvest Laws By State:
US Department of the Interior, Division of Scientific Authority, 2013
Videos on Ethical Harvesting and Stewardship
1Charron and Gagnon 1991
2Nantel et al. 1996
3Van der Voort and McGraw 2006
4Farrington et al. 2008
5McGraw et al. 2013 (review paper)
6McGraw et al. 2005
7McGraw, Souther, and Lubbers 2010
8Hackney and McGraw 2001
9Cruse-Sanders and Hamrick 2004
10Mooney and McGraw 2007
11Mooney and McGraw 2009
13Souther and McGraw in press (Ecological Applications)