About a month ago I was browsing the shelves of Woodward Library – UBC’s Science and Forestry Library – and stumbled across a book published in 1942 that sent me down a research rabbit hole about a native common tree in Pacific Spirit Park.
The book in question, actually a BC government bulletin, was John Davidson’s ‘The Cascara Tree in British Columbia’. If you are over 40, Cascara will have an immediate meaning for you: Laxative. BC’s Cascara Tree was once one of the most important and used medications in the world until it was replaced by safer alternatives and FDA approval was removed in 2002.
As the story goes, Frangula purshiana was given the name ‘Cascara Sagrada’ meaning ‘Sacred Bark’ by the Spanish explorers who found indigenous native cultures using it and were shocked by its healing power.
As Davidson explains in his 1942 bulletin, other laxatives on the market were habit-forming, caused stomach pains, and had serious damage on internal digestive organs. Cascara, on the other hand, didn’t cause stomach pains and “after a period of use, less is required, and as these muscles regain their normal function the use of Cascara is no longer necessary”[1]. A miracle drug! Gives an immediate fix as well as long term benefit without becoming reliant on it. And best of all it was natural and easy to obtain.
This belief about the incredible healing power of Cascara was very common at the time. It was widely repeated in newspapers articles, as in this 1928 article in the Globe and Mail:
The world’s best laxative is one that Mother Nature makes in her own laboratory. It is the bark of a tree called CASCARA. The Indians used to chew this bark – and reach old age without a sick day. It is the best thing there is today for any system; best for the blood. The most beneficial in its action on the bowels, of anything yet disclosed.[2]
Treatment for constipation was and still is a large public health concern. Some stats put constipation as impacting as many as 25% of Canadians. It is also important to note that science in the last few decades has showed that bowel movements can vary between three a day for some people, and three a week for others. There is a lot of misinformation about this upward mark of a three-a-week, with pseudoscience advocates claiming that having more regular bowel movements is healthier.
And pseudoscience was a big issue in the early 1900s. A famous British Doctor, Sir William Arbuthnot Lane, who pioneered some very important early medical procedures, later in his career became viewed as a crank because he promoted autointoxication or colon cleansing. He believed that “half-digested matter sitting in the gut for too long would begin leaking toxins into the rest of the body”[3]. He became obsessed with less frequent bowel movements being the foundational cause of most people’s health issues. Other pseudoscience supporters joined him in promoting these ideas, and convincing patients otherwise was a huge battle for frustrated doctors.
I recommend Elsa Richardson’s book on this and other historical issues around gut health. Here is a brief article from it focusing on Colon Cleansing and Lane.
So! In the early 1900s constipation was a serious health issue and there was a mistaken wide-spread belief that having more frequent bowel movements was healthier. Cascara was very high demand.
However, there was a lot of concern in newspapers at this time that Cascara trees were being cut down or burnt in the process of land clearing, without any awareness of their magical medical powers. BC was wasting a future industry and widely desired medicine. A 1925 headline in the Vancouver Sun:
The Headline: Big Fortunes in Cascara Bark go up in Smoke in British Columbia: Ignorant settlers literally burn up thousands of dollars every year – Immense Cascara industry could be built up for Canada in pacific coast province – Trees bear in ten to fifteen years – Government education campaign
Cascara bark was easily obtainable – the trees were everywhere around Vancouver – and miracle drugs are always worth a lot of money. It was relatively easy to collect as well, the laxative properties come from the bark of the small tree, which can be peeled off, dried, and then sent to a wholesaler, pharmacy, or sold to users directly.
The above 1925 article reports that $7.00 could be made a day by a Cascara Bark collector “without undue exertion”[4] this is an equivalent to $127.92 today. About the same as what a full minimum wage shift would get you right now. Also remember that rent was much smaller percentage of personal income back then! There was good money in the woods!
The article also mentions that “In the extension of the city of Vancouver, literally thousands of dollars worth of cascara bark were absolutely destroyed without anyone being the wiser” and gives the specific example of a recent empty lot where 94 Cascara trees were destroyed without being harvested. $80 worth in 1925. Equivalent to $1,461.94 today.
The promotion of harvesting Cascara bark for money worked. It became an industry. You can still find examples of seniors that remember doing it when they were younger for extra money or when between work (a few places on the west coast still do it).
It worked too well though. Soon incredible amounts of Cascara were being exported from BC and the fear began to grow that it would be over-harvested and completely removed from the forests.
This brings us back to John Davidson’s 1942 BC government bulletin. It had been originally published in 1922 and focused on promoting harvesting, but when it was republished in 1942 it focused on making sure the tree didn’t completely disappear from BC forests.
Davidson talks a little about attempts to setup Cascara Tree plantations (Cascara plantations never really took off and I can find a few anecdotes that the laxative effects were much better from wild trees) but the real important piece of the bulletin is his recommendation of a sustainable way to harvest wild Cascara Trees. That is, a way to remove Cascara bark without killing the tree. Now this is nothing new, indigenous peoples have been harvesting Cascara this way to use for medicine for thousands of years. Much like how cedar was harvested, they would take only a strip of bark from a healthy tree. Ensuring that the tree could grow around the wound and continue to be healthy.
Davidson recommends a more demanding harvesting method, but one that would allow the tree to continue living. He recommends, without using the term, coppicing. Coppicing is a truly ancient tree harvesting process, where the tree is cut down to the stump, and then the next spring new shoots will come up from the stump. Once these shoots have grown into new trunks and branches, they can be cut back to the stump again, and the tree will once again regrow the next spring.
This is a bit unbelievable, but it’s true, coppicing can allow trees to live for much longer than they normally would have. Trees that normally live a hundred years can live for a thousand when coppiced. Not all trees! This only works for deciduous, broadleaf trees, not conifers or needle leaf. Since deciduous trees regrow their leaves every spring, unlike conifers, they store large amounts of nutrients, sugar, and water in their roots that allow them to regrow. Some deciduous trees get exhausted after multiple coppices, but others, like cascara, keep going. Becoming a potentially eternal source of wood and life.
If you want to learn more about the mind-boggling phenomena of coppicing, I recommend William Bryant Logan’s 2021 award winning book, Sprout Lands – Tending to the Endless Gift of Trees.
When Cascara Trees were being harvested, their bark was cut away all the way to the ground. You need to leave some bark on the stump, about half a foot above ground, to allow the coppice to happen and the tree to resprout every year. Davidson was making the case that if we harvested Cascara this way, they would keep growing back year after year.
With this BC government bulletin Davidson wrote, there was a new law in BC. Anyone harvesting Cascara on public lands were required to get a – free! – permit to harvest. This permit required the trees to be cut down and the stump left with half a foot of bark. The permit wasn’t trying to restrict cascara harvesting, just trying to make it sustainable.
It was a praiseworthy attempt at saving the tree and it might be why we still have cascara trees around in Vancouver today. You don’t see clumps of them anymore like the 94 in that Vancouver lot but there are two trail sections of Pacific Spirit Park where you will see a lot of them. Along the south part of Top trail and the middle section of Hemlock trail. See the trails in red in the map below.
Have fun hunting cascara trees! I’ll be leading an forest walk soon where I will talk about them. Please subscribe to our Newsletter for updates about the date and time of this walk and other events.
—
Sign up for email notifications about future walks, talks, and articles from Ryan here
[1] Davidson, John. The Cascara Tree in British Columbia. British Columbia. Ministry of Agriculture, Victoria, B.C, 1942.
[2] “A Doctor Talks: About Cascara.” The Globe, Nov 10, 1928, pp. 9.
[3] Richardson, Elsa. “What History can teach us about constipation and the gut” Time Magazine. October 2, 2024 https://time.com/7027908/history-constipation-gut-essay/
[4] Chicanot, E.L. “Big Fortunes in Cascara bark go up in smoke in British Columbia” Vancouver Sun, February 7, 1925, pp. 4.