SpruceRoots Magazine - December 2000
Red Berry Green Tree
by Erica Thompson
Even to those who have celebrated a century of living, the yew tree is long an elder. Venerated as one of the oldest beings on earth the yew is said to be only less ancient than the world itself.
As written in the Book of Lismore, the earth's eternal cycles are patterned in life times of eagle, salmon and yew. "Three lifetimes of the eagle for the salmon. Three lifetimes of the salmon for the yew. Three lifetimes of the yew for the world from the beginning to the end." The forests where old yew trees can still be found are utterly woods long lived. However, the Pacific yew's fate is less certain than its historical stature would suggest. The BC forest industry, and the ministry governing its practices, are fickle managers, engaging in both disdain, reverence and disinterest, where the yew is concerned.
Thirty years ago, yew was an international celebrity. In hurricane flight from licensee burn piles, the tree became a national symbol of longevity and hope. A key to the long sought-after cancer cure had been isolated in its bark and needles distinguishing the yew, once again, as the 'tree of life.' But, however remarkable the promises held in it's genetic code were, and are, the events which followed the 'bark rush' are equally intriguing. To Chris Marrs and Mike Cheney, of Port Clements, the yew's story is our story. It is a touchstone revealing the whimsy of measure, worth and value. It is a real life history wherein savior and pest become one in the same.
Cheney is working at Marrs' small sawmill tucked into the edge of Port Clements. The waters of Masset Inlet are gunmetal grey and still, even beyond the west coast of Kumdis Island. In the mill shed, two newly planed boards lean against the wall, tangerine yew wood shavings covering the ground below Cheney's boots. The wood is elegant. Its tight grain revealing a long, slow steady life. There is more than a decade in the pale white sapwood alone. This is salvaged wood, picked up from a roadside, in accordance with Ministry of Forests' policy to make fallen yew logs accessible to those who can use them. Yew wood is considered a gem in wood working circles. So much so, it has been said a wheel barrow of yew is worth the weight of a loaded logging truck. But, that sentiment doesn't hold true across all circles, for one person's gem may be anothers trash. This quandary of identity is the twentieth century's legacy for the Pacific yew.
Prior to the taxol explosion, the yew had been considered a 'trash' tree defunct of commercial timber value. Like other species of contestable worth, yew were destined to the slash and burn piles. As a result, historical accounts say, "an unknown but unquestionably significant percentage of the original yew resource has already been destroyed by logging. In the process of harvesting Douglas Fir and other timber species, mostly by clearcutting, yew trees were either cut or knocked over and broken up by machinery. Yew trees were seldom taken in primary logging operations, but some yew wood was later salvaged by firewood cutters and gleaners gathering wood for specialty products. Most of the yew trees that existed in logged areas were burned in slash-disposal fires."1
It was the 1960's and the National Cancer Institute in the United States was running clinical trials on plant derived materials searching for a cure. While screening 35,000 plant species 'taxol' was isolated from yew bark and needles and found to have anti-cancer activity. Human trials began in 1983 and by 1988 preliminary results indicated it was an active agent in fighting ovarian cancer which had previously proven resilient to chemotherapy and was responsible for killing 12,500 women a year in American alone. Results for treatment of advanced breast cancers also looked promising. Taxol was "hailed as one of the most significant advances in cancer therapy in recent history." 2
During the early 1990's the American Food and Drug Administration approved taxol for commercial use. This decision held far reaching implications for the slow growing tree as contractors, looking for massive amounts of bark, went into the forests. "Hundreds of thousands of these trees were cut down and stripped of their bark. While most of the logs remain in the woods where they were peeled, many were actually hauled to log yards, piled and mostly burned," say reports dated 1991. 3
BC's Ministry of Forests' Western Yew Bark Register recorded 75,336.34 kg of dry bark harvested in 1991,1992 and 1993. Of this amount 60,199.19 kg's, nearly 80%, was provided by the Vancouver Forest District. 4 The amount of taxol each yew tree provides is minimal. Research indicated it would take "three to ten trees per patient. Others have claimed this number can be as high as 10 trees per person depending upon the size of the trees," says the Pacific Forestry Centre.5 As harvesting levels soared, information gaps surrounding the yew became abundantly clear. Inventories had never been kept before, little was known about how many yew were growing in provincial forest, how they reproduced, what types of habitat they preferred. Questions of scarcity arose.
The Ministry of Forests developed an intermediate policy in 1991 to 'support and promote the orderly harvesting of bark from western yew.' Assistant Deputy Minister of Operations, Wes Cheston, sent a letter to all regional managers directing them to include yew in provincial forest inventories via timber cruises. Yew stumps were to be cut above 15 centimeters in height, injury of small sprouts or branches growing up from stumps was to be avoided and a system of record keeping, such as the Western Yew Bark Registry, was set in place. This harvesting direction was intended "to ensure this species is not over exploited and will continue to exist in future forests." 6
Effective October 1, 1993, Policy 8.12 of the Timber Administration Manual went on the legislative books to ensure "the harvesting of yew bark will be planned to facilitate the long term survival of western yew and to maintain its genetic diversity."7 That same year, the first semi-synthetic processes for making 'taxol' was discovered and shortly thereafter the United States Department of the Interior, Bureau of Land Management, nullified their conservation-based Pacific Yew Act determining that "quantities of taxol sufficient to satisfy medicinal demands are available from sources other than Pacific yew harvested from Federal lands.
BC's Ministry of Forests kept their Yew Bark Harvesting and Collection Policy active, even updated it as recently as 1997. However, the evidence in Haida Gwaii's back country cutblocks is not what one would expect for tree proven, only decades earlier, to herald cancer cures. In the clear cuts at kilometer four of the Drill mainline, yew trees are being used for 'punching', forming a corduroy road on which the hoe travels to access more valuable timber. It is a grim state of affairs for the tree of minimal consideration; a species devoid of 'timber value.'
Marrs and Cheney travel Drill main towards cutblock 211 at kilometer four. They have been monitoring yew populations from Drill, to the Datlamen and outwards. Documenting the decline of island yew is hard work. Walking through forests, finding where the yew trees are, and then returning after they have been logged to look for them again, often deep under debris. They walk slowly. It is their concern, that yew trees are not regenerating. They have found only a handful of yew seedlings under shoulder height. They have been looking carefully, Marrs has been paying attention for nearly twenty years.
"Yew is a huge missing component," says Marrs. "You just have to stand on the landscape and see that it is missing. It is so obvious that it is being neglected to the point where there is a lack of juvenile trees. The vision is that there will be, at some time in the future, an old growth forest. But how much reality is there actually in that? The component of the yew is going to be gone because there is not the idea of preserving it for the future. If there is no future of old growth, then there is no future for the components of an old growth forest."
Standing on the backside of the block, Cheney poses a challenge: "try to find a seedling shoulder high. The only person who has ever said anything to me about seeing seedlings come back in second growth claimed he had seen lots of them. I asked him how he told the difference between yew and hemlock seedlings. That is the skill testing question; and he failed."
In the midst of Drill 211, there are yews but they are not standing. Some of the trees have been ripped out of the soil; their roots exposed. Others, still in the ground, have been snapped in two and splintered by equipment. Most puzzling are the three yew, within a thirty meter area, which have been cut down and used for punching. Further up the slope is another section of hoe road where there are yews, metre after metre, buried under cedar and hemlock, sometimes crushed down into the subsurface.
"The yew have all been removed," Marrs says, pointing to the upper slope of the block. "Those tiny pieces of yew in there represent a lot of value and you could make a lot of kayaks with that cedar...but it is crushed, pounded with a bucket so it breaks open , it is driven over, back and forth, to support the machine just because they aren't using alternate harvest systems, variable selection systems. This is an inexpensive way of getting the wood out as quickly as possible and this is what we as the public have to pay for."
Marrs and Cheney agree the reason for the destruction and disinterest in yew trees rests on its lack of timber value and its misfit with the speedy rotations of managed forests. There is ample evidence that their argument is sound. According to economist Timothy Swanson, countries choose to invest "limited funds in the management and production of some species and not in others. Non-specialized species," he says, "may be lost through under-investment before they are lost through direct replacement." Following Swanson's line of thought, the yew's low timber value, contrasted to the costs incurred in harvesting it, or in logging around it , and its slow growth rate, relative to other species, mean high stakes for its long-term survival.8
"It is almost as if yew is out of their game. Their game is a seventy-year, or eighty-year cycle. This is a three hundred year old cycle and they don't like any whiff of that," says Cheney. According to Marrs' experience, yew benefit from a forest canopy, which means established cedar trees before the yew experience optimal conditions. They aren't buying into the MOF's policy. The regulations have enforced what they see on the landscape. "It is obvious when you are out there that there is no policy ... the claim that there is a sustainable development based policy that is active is ridiculous," Cheney says. "In the cutblocks where there is lots of yew wood, they just cut it down and they trash it too. I would say at least 30% of it is in punching and I think I am underestimating that."
Queen Charlotte Ministry of Forests Timber Officer, Dan Biggs, says there have been relatively no issues surrounding yew trees at the local office. The same policy developed during the taxol days is still the governing yew management and the long term survival of western yew is still MOF's priority.
One way MOF says they facilitate the survival of the yew is to leave trees standing in a cutblock once the rest has been logged. However, this measure often proves difficult to achieve on the landscape. According to Biggs, it may be a patch of yew, which is left standing, though "quite often it is a lone tree." As you can imagine, he says, if a licensee is clearcutting a block, and there is a big patch of yew is in the midst of it, the yew will be a obstacle to getting at the more valuable wood behind it. In such cases, those trees end up getting logged. So, if they are left in a block it is usually just a single yew tree, two or three trees, but rarely a patch of them, says Biggs.
If people are concerned about yew growing in cutblocks, MOF advises they contact the ministry or submit their comments during the review period of the forest development plan in question. Comments drawing attention to high yew concentrations, missed by timber cruises, or comments from the Haida saying that "there is lots of yew there and they are interested in collecting it for medicinal purposes or whatever," says Biggs, would trigger its inclusion in the development plan process. "We haven't received any comments like that. If those comments come up then the district manager would have to consider it," he says, and direct the licensee, who would then design a means of dealing with the issue.
"The bottom line is it isn't really a big issue here...it is not something that is of big interest or has a big profile. I have been here for just over three years and like I say it has only come up twice, and that was about two years ago. There were permits that we were issuing and there was some yew in it and we were directing the licensees to leave them standing or if they had to fall them to pull them to the roadside...there were only two permits we issued that had those conditions on it, where the yew had actually shown up on the cruise compilation. Probably the reason for that, is yew mainly grows on the low volume sites, and for the last two years the markets have been really bad and the licensees haven't been interested in going into those low type cedar sites," says Biggs.
The survival rate of the yew left standing in a clearcut is questionable. The Pacific Forest Centre has studied yew's ability to tolerate direct sunlight and to continue living without forest canopy shade, though the results appear to be inconclusive. Regarding the tree's ability to tolerate high levels of sunlight studies find, "the foliage of the Pacific yew also has the capacity to produce pigments which apparently act to protect the foliage from high levels of sunlight. These pigments tend to give the foliage a bronzed colour. We have observed low temperatures and poor nutrition can increase bronzing, so high levels of these pigments may indicate stress in the trees."9
Research Scientist at the Pacific Forest Centre, Dr. Al Mitchell, has studied Pacific yew all over the province, including samples from Haida Gwaii. He agrees finding seedlings in forests and clearcuts is not an easily rewarded effort. But, he does believe yew seedlings can survive in clearcuts though they may look quite different from those growing up under the canopy. "What looks really bad may not be so bad," he says. There is very little regeneration data and traditional inventory strategies have proven to be largely unsuccessful when applied to yew. But it is a resilient tree, a species which never ceases to amaze Dr. Mitchell. One which is able to keep living under a very wide variety of conditions, he says.
In cutblocks on Graham Island, the brown needles of standing and fallen yew are easily discerned from the waxy green of living needles. Marrs and Cheney use the brittle and brown branches as markers while tracking trees. "When they grow up under the canopy, the needles are luxurious and dark green and usually they are big. If they have been sitting like that," referring to trees left in open clearings, "the needles don't seem to grow that long and they start to yellow and brown, going that copper colour eventually," says Cheney.
Deer browse is also a barrier to yew regeneration. Where you find cedar at risk from browse the impact on yew is amplified since there is significantly less of it than cedar to start with, says Marrs. "It is just not coming back at all. There are a few cedar trees coming back. There is no yew wood."
Wild cedar seedlings may take five years to achieve some kind of viability, to reach a metre or a metre and a half, says Cheney, but for a yew tree it probably requires twenty or twenty five years of growth before it of a viable size. "It apparently never gets there."
In the Forest Biology lab at University of Victoria, Erika Anderson is wrapping up her doctoral research on the reproductive success of the Pacific yew. Her findings have yet to be published but the preamble is not encouraging. Studying yew populations in BC's coastal forests, Anderson reports the seed efficiency of yew, or its ability to successfully mature into a seedling, ranges from 0-16.2%, averaging 4.5%.
"These numbers were found after tagging approximately 250 developing seeds in 1997 and 1998 at two sites on southern Vancouver Island. These seeds were followed throughout the season until the seed aborted or matured," she says. The slim rate of survival is dramatic in comparison to hemlock's success which is in the vicinity of 70%.
According to Anderson, the successful regeneration of yew is equally challenged in natural forests as in clearcuts. Studying natural forest systems, she identifies factors such as scattered yew populations, low levels of pollination from male trees, historic reduction of yew out competed by western red cedar, and destruction of reproductive and vegetative buds by the yew big bud mite, for the species decline. These factors, working in concert with low seed success to limit the number of yew seedlings growing in BC's forests. Trying to be optimistic, Anderson says, "one promise for the future is the longevity of yew seeds which can remain dormant, though life storing, in the soil for many years."
Marrs, Cheney and Anderson share a deep concern for the future health of Pacific yew; a sense of personal duty translated through years of research, and miles of walking, searching for seedlings and a sense of hope for future forests. Inherent to their actions is an understanding of value, worth and a keen awareness of how ancient a player the yew is in earthy cycles, in cultural identity and as a member of whole forest communities.
Anderson is excited to hear of Marrs and Cheney's commitment. "I am very impressed that people take the time to notice yew trees," she says, "sometimes I feel I am writing the epitaph of yew."
8 Timothy Swanson, The Valuation of Biodiversit and Biotechnology, Industry Canda, 1998.
SpruceRoots Magazine - December 2000