Q. Marijuana is being accepted as a legitimate medical treatment in more and more parts of the United States. Even its use as a recreational drug has been legalized in many areas. From an ecological standpoint, does the production of marijuana as an agricultural crop cause environmental damage?
A. Marijuana (aka cannabis), native to Asia and in the same family as hackberry trees, is an enigmatic plant. A complex assortment of laws and regulations, nationwide and internationally, surround marijuana. Canada allows cannabis use in any fashion. All but six U.S. states allow some level of medicinal use of the plant. Almost half the states allow full use for any purpose. Only four states (Idaho, Wyoming, Kansas and South Carolina) still decree that any use of marijuana, even for medicinal purposes, is fully illegal.
![The leaves of a cultivated Vitex plant (chaste tree) have smooth edges; otherwise they resemble marijuana leaves. [Photo courtesy Whit Gibbons]](https://www.gannett-cdn.com/presto/2022/06/22/NTTN/29262ace-6f30-4b62-81a5-451e64709356-06-26-22_CHASTE_TREE_VITEX_by_Whit_Gibbons.jpg?width=300&height=331&fit=crop&format=pjpg&auto=webp "What is the environmental impact of marijuana?")
Except for a few holdouts, states from coast to coast are beginning to embrace marijuana as an acceptable form of pain reliever and as a recreational drug. Its recorded use by humans dates back more than 2,000 years. Current consumer demand ensures that the crop will continue to be grown at agricultural levels. Tax codes and other legislation concerning marijuana as a commercial crop vary significantly from state to state. Cannabis is grown (legally and illegally) everywhere in the world except the Arctic and, as always, the Antarctic.
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Land use practices that promote growing any plant as a monoculture on a commercial scale inevitably lead to the demise of some local native species. It’s a basic ecological principle that plants compete with each other for space and resources. When humans are involved in ensuring the welfare of a marketable species, wild plants will eventually be reduced in numbers and perhaps even eliminated entirely. The loss of such native plants means the animals, including insects, that depend on them will also decline in numbers.
One of marijuana’s greatest negative environmental impacts could well be the result of law enforcement efforts to destroy the crops. Such environmental disruption probably has detrimental effects on the natural habitat where marijuana is being grown. A byproduct of the legalization of marijuana might be a decrease in environmental destruction by law officers trying to eradicate marijuana crops — and subsequent savings of tax dollars.
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An inventory of plant products worldwide that people inhale, drink, eat or inject for pleasure, sometimes with addictive consequences, would be near endless.
Heroin (as well as morphine, codeine, and the once-ubiquitous paregoric that relieves upset stomachs in babies as well as adults) is produced from the opium poppy. The poppy family includes hundreds of species of aromatic, often brightly colored plants. The opium poppy is the only species within the family grown commercially on a large scale.
The largest crops are in Afghanistan. Growing wild, none of the many kinds of poppies have a significant negative environmental impact on the habitat. Some species are pollinated by bees, flies, and beetles, and the plants may provide nourishment to these insects. The overall environmental impact of poppies is best measured by how much land is cultivated for opium poppies, thus making it no longer available for native species in their natural habitats.
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The South American coca plant, from which cocaine is derived, belongs to a family with more than 200 species. Like the opium poppy, coca is the best-known species in the family. According to one scientific study, “cocaine functions in plants as a natural insecticide.” The major environmental impact is primarily a consequence of cultivation practices. The cocoa tree, the source of cocoa powder and chocolate, is also native to tropical America but belongs to a different family from the coca plant.
The widespread production of all manner of goods derived from plants — from drugs to dog food to cotton — has some kind of environmental impact. But regulations on marijuana and other recreational drugs are influenced by cultural attitudes and politics. They have nothing to do with ecology.
Whit Gibbons is professor of zoology and senior biologist at the University of Georgia’s Savannah River Ecology Laboratory. If you have an environmental question or comment, email [email protected]
