About wood and woodturning, observations of nature, links to things I find interesting, and other topics at whim. If you like the woodturnings shown here, please come visit my new shop at NoSkewTurns.com to see my latest work.
15 July 2005
The Cascara Buckthorn tree has long been known for the laxative properties of its bark. Stripped in the spring, dried, bottled, and marketed as Cascara Sagrada, the bark was in such high demand in the early-to-mid 20th century that the small trees were severely overharvested. Harvesting cascara bark entails killing the tree, and so throughout much of its native range, primarily the western side of the Cascades in the Pacific Northwest, cascara, never very abundant, became quite scarce. (In my woodturning club, some members whose fathers or grandfathers had once made a living as "chittam bark" peelers, had never themselves seen the tree or the wood.)
Cascara buckthorn, Rhamnus purshiana, grows at lower elevations in moist areas like those suitable to red alder. In such conditions a mature tree may grow to 35 feet tall, and no more than 12 inches in diameter, usually smaller. It has rather large, somewhat glossy leaves with prominent veins, and bears a modest crop of 1/4" berries that ripen from red to glossy purple-black in late August. These berries are eaten by many birds, as well as bears, raccoons, and other animals.
Fortunately, the seeds benefit from passage thru the guts of animals and birds, and the latter have no doubt been highly instrumental in redispersing the species through much of its former range. When I identified my first cascara tree, about 1990, I knew of only two on my property. By the time I sold the place in 2004, I had discovered several dozen additional trees on the forty acres, almost all less than 20 years old. One cluster of several vertical tree-sized branches had sprouted from an older trunk which apparently had fallen or been pushed over, but remained rooted.
Because cascara is such a small tree, the wood itself is considered to have no commercial value. Therefore, the stripped trees were most likely left to decay, or possibly cut for firewood. But I have discovered that it is a very nice turning wood, with subtle character and often, surprising color.
When freshly cut, cascara sapwood is a pale yellow, and the heartwood, which makes up about a third of the diameter of the trunk and larger branches, is almost a pumpkin orange. As the wood dries, the sapwood seems to get paler, and the heartwood color becomes more muted. Drying also seems to induce unexpected color zones in the sapwood, which I am still studying to try to determine their cause. In the picture at the top, you can see darker areas in the sapwood of the log section, which appear as purplish streaks on the box. The wood here was perfectly sound, so it doesn't seem to be related to decay, the way spalting is.
Just outside the heartwood in the log is a barely perceptible ring, which unfortunately did not appear on the box made from the adjacent section. A few years ago I found a long, dead branch hanging from one of the trees. It was sound and perfectly dry, and just inside the outermost edge of the sapwood, was a ring of color that I have not seen in any fresh-cut branches.
I made these little weedpots by centering the branch so that the belly curve would pass thru the color ring. Note the subtleties of color. The rings often have pale pastel shades of blue and purple, plus hints of sage green and gray. They look like they are painted on!
[Update 20100301: I swapped out the original picture for a better one showing the "picture frame" effects, and edited the text accordingly. Lea]
I also made a small, straight-sided cup from this branch, but unfortunately, while the colors were even more visible, the photos I took were out of focus, and I no longer have the piece.
After the 2004 ice storm, several of the larger, more exposed trees on my property were severely damaged, with their branched tops bent ninety degrees and the wood splitting at the bend. I cut these trees into long sections, sealed them, and put them aside to dry. Based on the faint ring that has appeared in the one log section, after only a year of drying, I am hoping that some of the other pieces may develop color rings as vivid as this branch.
Even without the color band, cascara can be very beautiful. The fine-grained sapwood displays a subtle chatoyance, almost like the moire patterns in fine curtains. On one of the larger trees I took down, the cross-section revealed that every growth ring was finely rippled, like the edges of paper cup-cake pan liners. Now that will be some spectacular wood in four or five years!
I am most careful not to put my hands near my mouth when working this species. Otherwise, I take only normal precautions against dust and chips when turning cascara, and have experienced no side-effects from the bark, even when turning it green.
Dry cascara turns easily. The wood is fairly hard, about like big-leaf maple, and shows no tendency to chip. It polishes up beautifully, as you can see, and I have used only clear shellac or, on the weedpot, just beeswax, to avoid darkening the colors. My first attempt to turn green cascara, however, was rather a disaster. There was a very noticeable difference in density between the heartwood and the wetter sapwood - the latter seemed almost to shred and I ended up with something akin to firewood rather than a turning. In hindsight, much might have been due to poor technique or less -than-sharp tools, but at least some of it was due to the wood itself.
A fascinating and unexpected fact about cascara, which I only learned recently, is that it is closely related to Pink Ivory, Rhamnus zeyheri. Pink ivory, which grows in southern Africa, is considered one of the most rare, expensive, and beautiful woods in the world. In my opinion, cascara, its humble North American relative, is also deserving of some respect.
Update 20100301: The broken picture links have been fixed.
Back in April, I wrote at length about the new Pacific Northwest Woodturning Guild. The guild website is now up and running, and has photos of members' work, links to local galleries that sell woodturnings, and other information. The How-to-join page allows prospective members to download the application form as a PDF file for printing.
To give you an idea of the caliber of work done by our guild members, several of our members had pieces accepted for display in "Art Beneath the Bark: A Celebration of Woodturning", the featured exhibit at this year's Lake Oswego Festival of the Arts, held June 24-26 in Lake Oswego, OR. The exhibit comprised approximately 150 pieces of turned wood art, from nationally and internationally known turners who were invited to participate, and from Pacific Northwest turners whose works were juried in.
More than twenty-five woodturners from the two local woodturning clubs and the guild volunteered as docents for this exhibit. I worked a three-hour shift on both Friday and Saturday, and had an absolute blast! Not only did I get to admire many exquisitely beautiful turnings, but I got to talk to lots of people about woodturning and trees and how did they DO that?? and just radiate my passion for wood and turning and why it is so much fun!
As I was leaving Saturday evening, Corinna Campbell, who has designed the Special Exhibit for several years, told me that as a group, we woodturners were the most knowledgeable and enthusiastic docents she had ever worked with at the Festival!
Although the website preceded it by a week or so, the Lake Oswego Festival was basically our public debut. In addition to the pieces in the Special Exhibit itself, we had a very nice poster on the "handouts" table by the door, along with our just-off-the-printer brochure and flyers. It will be interesting to see in the next few weeks or months what the response will be, both in new members and prospective customers.
I bought an American flag kit yesterday, and set it up to be displayed from the steps on the east side of the house. It's a full-size "house" flag, 3' by 5', that is visible from anyone driving along the gravel road. Although I'm not an early riser, I got up at 6:30 a.m., and with the morning sun just above the hills and full in my eyes, I carefully unfurled the flag, settled the pole in the bracket, and tied the halyard to the brace.
In past years I never gave much thought to flying the flag on the Fourth of July, or any other day. Our old house was hidden in the middle of 40 acres of woods, at the end of a pot-holed lane. No one drove by except solicitors and evangelistic types, and we discouraged even those by letting the blackberries grow tall and thick along the road. The nearest neighbors were half-a-mile away and out of sight. There would have been no one to notice a flag, or to misinterpret the lack of a flag as indifference.
Things have changed a great deal for me this past year. Not only have I moved, but I've become ever more aware of the growing threats to the ideals and principles upon which this nation was founded. The concepts of liberty, justice, personal freedom, independence, the rights of property, self-defense, and free speech, are being dismantled and gutted by our own government officials, both elected and appointed, because as a nation we have allowed each new generation in the last 60 years or so to grow up more ignorant of our history, and the world's, than the last.
I don't normally discuss politics, and I'm not about to do that here. But I find it distressing that, as a nation, we are fighting to bring freedom to other countries such as Iraq and Afghanistan, while as a people, we are allowing those same freedoms to be stolen from us bit by bit, with only a small but vocal cadre of defenders crying into the wind to be heard.
Several times during the day, I checked on the flag. A couple of times I noticed the light breeze had wrapped the flag around the pole, or flipped it up over the end, so I went out and carefully loosened it to fly freely again.
In the late afternoon, I drove down to Portland, and on the way back, I decided to pay attention to how many flags I saw. It was not a totally bleak picture, but the turnout was much less than I expected. Of the businesses that were open on the holiday, I saw (multiple) flags on many car dealerships, and on every fireworks stand, but very very few others. In the urban residential areas I passed thru, perhaps only one in twenty or thirty houses had a flag flying.
I got off the freeway in Vancouver, and took surface streets the remaining thirty miles home. Newer developments with $250,000-and-up houses had almost no flags visible. Only when I got into the more rural sections of the county did I start to see a few more flags. One here, two or three in a row there, most often on older or smaller houses. I even spotted one or two houses that were set back behind trees, where no one not specifically looking would even notice, that had a flag flying proudly from a real flagpole. I found myself saying "Thank you!" out loud to each such household that I passed.
On the whole drive, sadly, there was not enough display of color to even remotely suggest to a foreign visitor that today we were celebrating our nation's independence. Only the closed businesses and the fireworks displays would hint that it was a national holiday.
I got home, untangled my own flag once more, and fixed dinner. At 8:55, just before official sunset, I went out, removed the pole from the bracket, carefully furled the flag around the pole, and brought it inside.
Why did I fly the flag today? For many reasons. To honor my father, my late uncle, my brother, my brother-in-law, my husband, all of whom are veterans. To celebrate our history and our continued independence. Because this is a country where one can freely choose to fly, or to not fly, the flag, without fear. To show that I believe in the ideals upon which our constitutional republic is based. To support our troops around the world who are fighting to bring freedom to countries and peoples threatened with enslavement by fanatical leaders. Because I understand that World War IV, the war against terrorism, must be fought unrelentingly, and that we must win, if our grandchildren are to have a hope of growing up to proudly, and freely, salute that flag.
After I brought in the flag, I called my father, who was stationed in the South Pacific during World War II, and simply told him, "Thank you for serving."