Welcome to the new OALA website! Please click here to read the FAQ
Bank of Canada Head Office Renewal, DTAH

Diana Beresford-Kroeger: Battling climate change with trees for life


Boreal forest, Manitoba. IMAGE/ Call of the Forest movie/Laura Lamont

Here are a few things you should know about Diana Beresford-Kroeger. When she calls you a lunatic, she means it as high praise. She can be stern and impish—pretty much simultaneously. She doesn’t have a computer or send email, and yet she is one of the most connected people you’ll ever meet, referencing the most recent scientific studies and cutting-edge research. She lives a simple, frugal life, yet happens to be the granddaughter of a British lord, orphaned when she was very young. She talks in mystic, heartfelt terms about the Druidic Celtic culture, then mentions that she is the inventor of an artificial hemoglobin used for tissue transplants.

Diana Beresford-Kroeger. IMAGE/ Call of the Forest movie/Laura Lamont

But one thing about Beresford-Kroeger on which there is no apparent contradiction (and I stress apparent, because all of the above makes perfect sense when you speak with her, read any of her numerous books, or watch the documentary about her work, Call of the Forest) is that she is passionate about trees: “As long as there’s a breath in my body,” she says in an interview, “I’ll try to save the forest and stop climate change.”

Beresford-Kroeger was a keynote speaker at the 2018 CSLA/OALA conference, held in Toronto in April, and her wide-ranging, engaging speech was distinguished by a fluid movement between science and poetry. In one breath, she referred to “listening to the sound of the universe,” and then switched to a rapid-fire explanation of the glandular tissue of Thuja occidentalis.

Nuts of black walnut tree. IMAGE/ Katja Schulz/Flickr
Upright female catkins and hanging male catkins of yellow birch. IMAGE/ Plant Image Library/Flickr

While scientific training can dim the potential to see magic in the world, for Beresford-Kroeger it has clearly heightened her innate respect for mystery. “Trees are more complex than we are,” she notes. “We don’t even fully understand how transpiration works.”

Reverence for the unknowns of nature doesn’t mean that Beresford-Kroeger isn’t certain about our current realities: “We’ve taken down too much forest,” she states simply, and her life’s work is to repatriate lost species in order to replant the planet— something she has termed bioplanning—as a “foundation of resilient sustainability.”

Where Beresford-Kroeger departs from traditional tree-planting messages, though, is in her emphasis on the health-giving properties of trees, using terms you’ll rarely hear from a forester. Plant black walnuts, she urges, for their ellagic acid that absorbs harmful aromatic hydrocarbons from the air. Plant willows for their phenolic compounds that relieve anxiety and depression. Plant yellow birch for the anti- prostate cancer compounds it emits into the air. Plant eastern white cedar to boost your immune system and steady your pulse rate. “These are medicine trees,” Beresford- Kroeger points out, exhorting landscape architects to include health attributes in their considerations for design.

Her message is as practical as it is aspirational: “Dreams help the mind climb into impossible territory,” she says. Specifically speaking to landscape architects, she asserts, “You’re the people who have the dream.” But then she’s back to earth: “Live like a groundhog—doggedly, with purpose, just do it.”

The “it” is the essence of her passionate, practical aspiration: “We can stop climate change.”


Diana Beresford-Kroeger’s book Arboretum America (University of Minnesota Press, 2003) is a treasure trove of information and inspiration about trees. The following details, and quotations about particular species and their medicinal benefits, are gleaned from the book.

Pine (Pinus): Beresford-Kroeger refers to pines as “living pharmacopoeias,” and says that pines are the source of an important antibiotic called pinosylvin.

Sugar Maple (Acer saccharum): The sap of sugar maple contains acetol, which acts as an antistroke agent “by having a hemodilution effect on the blood.”

Ash (Fraxinus): The bark of ash species contains escin, “a potent biochemical complex used in the treatment of peripheral vascular disorders.”

Honey Locust (Gleditsia triacanthos): Fustin and fisetin, two chemicals found in the heartwood of honey locust, “have potent anti-carcinogenic action.”

Cucumber Magnolia (Magnolia acuminata): Beresford-Kroeger suggests that cucumber magnolias should be planted at hospitals, clinics, and retirement homes, due to the beneficial effects of the flower’s fragrance, which contains volatile lactone chemicals that, when breathed in and absorbed by mucosal membranes in the nose, “help settle the rhythmic pumping action of the heart,” and have general calming effects.

Oak (Quercus): The chemical quercitrin, found underneath the bark, is an important vasoactive drug that helps control blood pressure.