Macdonald knew nothing of the trees’ provenance as he had been living in England when they were first planted, but he went immediately to the garden’s accession records to see if they might be related to the tree he had read about in the paper. UBC accession number 18012-0358-1978 is described as a “golden Sitka spruce” (Picea sitchensis ‘Aurea’); the source was the Queen Charlotte Islands. They had to be from the same tree. The specimens, it turned out, were the all-but-forgotten legacies of three men: Gordon Bentham, an amateur conifer enthusiast, Oscar Sziklai, a Hungarian plant geneticist, and Roy Taylor, a former president of the Chicago Horticultural Society and director of the Chicago Botanic Garden, who had been Macdonald’s predecessor at UBC. In 1968, the same year he became the director of UBC’s botanical garden, Taylor copublished a two-volume, eight-hundred-page survey of the flora of the Queen Charlotte Islands. Amazingly, Taylor’s books made no mention of the golden spruce, but he was well aware of the tree and hoped to acquire a specimen for UBC. He would end up with two of them, but it would take more than ten years. As it turned out, the golden spruce was extremely difficult to reproduce.
Since the early sixties, senior foresters at MacMillan Bloedel had been hoping to propagate the golden spruce for the company’s arboretum on Vancouver Island. Their interest in it coincided with a period of new and aggressive research into tree breeding and propagation as MacBlo sought to develop plantations of “elite” Douglas fir that were selectively bred from the finest wild specimens. In order to do this, the company had retained Oscar Sziklai, a pioneer in the field of tree breeding and one of 250 students and professors from the forestry school at Sopron, Hungary, who immigrated to Canada en masse following the unsuccessful Revolution of 1956. With support from H.R. Macmillan, they ended up being hosted by UBC’s nascent forestry program, where Sziklai became a full professor. Throughout his career, he participated in scientific collaborations and exchanges across Europe and Asia, and in 1986 he became the first foreign member of the Chinese Society of Forestry. Sziklai’s original interest in the golden spruce lay in the question of whether its golden quality could be passed down genetically. However, closer inspection revealed that the tree was sterile; it produced very few cones, and none of their seeds appeared to be viable. This detail is consistent with a version of the Haida story which claims there were two golden spruces and that the second tree was a “male,” unable to reproduce.
Shortly before he died in 1998, Dr. Sziklai told a journalist that, on one of his many visits to the golden spruce, “a Haida princess guided us to the tree and said, ‘If the tree dies, the Haida Nation will die.’” At the time, Sziklai was a prominent scientist under contract with the country’s biggest lumber company, and yet after thirty years, he still remembered this encounter; it may have been another reason he took such an interest in the tree. There was no guarantee that attempts to clone the tree would be successful, but if it could be done, Sziklai was the man to do it. He was given the job on one condition: that he would keep his findings secret. “I wasn’t allowed to come to the public loudly and say, ‘We can propogate it,’” he told a reporter, shortly after the tree was felled. “They guarded this tree closely to the heart, and felt the public would strip the tree and it would disappear.”
“If we’d publicized it,” said Grant Ainscough, a former chief forester for MacMillan Bloedel, “we’d have had nothing left but a stump.”
In the 1960s, the propagation of West Coast timber species by artificial means wasn’t all that well understood, and no research was being done into Sitka spruce because it wasn’t a commercial priority at the time. The preferred method of propagation was to take cuttings—scions—from a desirable tree and either graft them to other rootstock or plant them directly. Either way, it was a crude process that generally began with a blast from a hunting rifle because the easiest way to take cuttings from big trees is to shoot them off. Professor Sziklai, in particular, was known for his expert marksmanship; armed with a pump-action Remington, he was able to knock down individual cones from over a hundred metres away. What propagators didn’t know forty years ago was that each part of a spruce interprets its genetic and hormonal instructions literally. Like a dog, the older a Sitka spruce gets, the harder it is to teach it new tricks, and like a member of a rigidly structured caste system, a branch never forgets its place in the pecking order. Thus, if your scion comes from a lower branch growing out of a trunk as old as the golden spruce, it will continue trying to fulfill its mission of being that branch, even when it is grafted to different rootstock, or planted vertically. Eventually it was discovered that branches closest to the apex of the tree were more willing to adapt to a new role—that of an upward-growing leader or trunk (which is what propagators generally want). It is because of this that when the top of a hemlock, cedar, or spruce gets blown off, you will often see the topmost surviving branches bending upward to replace the lost leader, giving the tree the appearance of an enormous candelabrum.
Sziklai chose to treat his cuttings with a rooting hormone and “set” them directly into soil, rather than graft them, and the results were discouraging. Of the two dozen cuttings planted, only half of them took root, and from then on their prospects went from bad to worse. According to a MacMillan Bloedel newsletter from 1974, despite “meticulous care and attention,” only three of these original cuttings retained “their golden tones,” and none of them grew at a normal rate. “Nature,” it said, “appears reluctant to duplicate a rare, beautiful mistake.” (One of these golden clones was presented in secret to H.R. MacMillan himself, but it died not long after.) Although Sziklai made more than one attempt, only a very few of them survived; despite being close to forty years old, the most vigorous of these is less than six metres tall and the only reason it is growing vertically is because the tree was bound to a stake for its first ten years. Something was clearly missing; moisture and cloud cover were obvious guesses, as most of the cuttings were planted in southern British Columbia, but there may also have been some more elusive, perhaps ineffable ingredient.
CHAPTER TWELVE
The Secret
Grey, dear friend, is all theory,
And green is the golden tree of life.
—Johann Wolfgang von Goethe, FAUST
FROM THE POINT OF VIEW of physics, all of us are rebels because we spend our lives actively subverting the forces of gravity and entropy, two of the fundamental laws to which all earthly matter must ultimately answer. But the tree is the greatest living symbol of this twofold defiance. Trees are simultaneously photo-and geotropic; that is, they are programmed not only to seek out the shortest path to the noonday sun, but also to directly oppose the downward pull of gravity. This is why most trees tend to be straight, well-balanced, and, relatively speaking, tall. What is more, they pursue these radical objectives tirelessly, in some cases for millennia. Viewed in this way, it could be argued that trees represent aspiration and ambition in their purest forms. Simply by daring to take root and grow, they bellow: “We refute gravity and entropy thus!”
Lots of people take inspiration from trees and forests, and we often like to think of them as sanctuaries of peace and tranquility. But this is deceptive; forests are, in fact, ruthlessly competitive places, where trees—and even branches on the same trunk—are engaged in life-and-death struggles for optimal position. The winner in this slow-motion race for space and light is determined by the tree or branch that photosynthesizes fastest and best. Photosynthesis, the process of manufacturing usable energy (carbohydrates) from sunlight and carbon dioxide, takes place in a tree’s leaves or needles, and is an enormously complex process. Part of it involves the breaking down of carbon dioxide molecules. Our lives literally depend on this, because it is from this gas that the tree derives the oxygen we breathe. The overpowering need for sunlight is one reason West Coast conifers get so tall so quickly. Conversely, when such a tree is grown in isolation from its neighbours, it will concentrate on girth rather than height, resulting in a fatter, bush
ier version of its lean, competitive counterparts in the forest.
But no matter how vigorous a tree may look on the outside, this, too, is mostly illusion: like the earth’s crust, the live portion of a tree is only a thin veil covering an otherwise lifeless mass. As counterintuitive as it may seem, a dead tree, shot through with moulds, fungi, invertebrates, and bacteria, contains far more living material. The live portion of a healthy tree represents only about 5 percent of the total; the rest is just scaffolding, not unlike a coral reef. Beneath its greenery, a tree is really a series of concentric tubes, each of which performs a specific function—defensive, vascular, or structural.
The outermost “tube”—the bark—functions much like our own skin: it protects the tree from external attacks such as animals, insects, and fire, and also helps to contain the fluids that keep the tree alive. Its thickness varies according to the needs of the tree; while the bark of a beech tree, for example, is less than two centimetres thick, the bark on a big Douglas fir might be twenty centimetres through. Douglas fir thrives in the drier ground of the northwest where thick bark is helpful as a fire retardant. It is also heavy; loggers have been killed on occasion by falling “walls” of this tree’s bark. Just inside the bark is the tree’s vascular system, which is not much thicker than a piece of cardboard. While photosynthate, which originates at the leaves or needles, is drawn inward to feed the rest of the tree, additional nutrients are drawn upward from the earth in a matrix of water through a process called transpiration. In this capacity, a tree operates like a giant straw with many subdividing lines. In the case of a big West-Coast tree, an individual molecule of water may take a week or more to travel from root to branch, and yet such a tree can release thousands of litres of water into the air each day. Under the right conditions, a forest can generate its own fog and rain.
Sandwiched within the vascular system is the cambium; only one cell thick, it is this gossamer-thin “tube” of tissue that actually generates a tree’s wood in the form of annual rings. Inside the cambium and vascular layers is the “dead” central core of the tree; its cells may hold and transport water, but they are not alive in the sense of being actively engaged in the construction or maintenance of the tree. Over time, the water in these cells is replaced with a rigid, epoxy-like substance called lignin, which gives a tree its strength. And this—the tree’s cellulose—is where the money is. An amazing variety of things can be made from it—things as crude as charcoal and lumber, and as refined as rayon and cellophane. Even so, when you compare the elegance, economy, and complexity involved in the making of a tree with our various attempts to exploit it, we look like so many cavemen banging sticks together.
Photosynthesis is a true natural alchemy; it is what allows a plant to, literally, build itself from air, water, and light—from “nothing.” This is an awesome feat on any scale, but it beggars comprehension when one considers the sheer mass of material that must be generated in order to “build” a sequoia, a redwood, or a Sitka spruce tree. In the case of the golden spruce, however, the ability to do this was severely compromised because any needles exposed to sunlight had their chlorophyll drastically depleted. Chlorophyll is the green pigment in leaves and needles and it is what makes photosynthesis possible. In terms of its ability to convert energy, the golden spruce’s impairment could be compared to a person with lungs that function at a third of their normal capacity. For this reason, no one is quite sure why the golden spruce was able to compete so well against healthy trees for three hundred years, or why it was able to grow to over fifty metres tall.
A tree that exhibits this pronounced yellowing is called a chlorotic, and while it is not uncommon to see a chlorotic branch—or “sport”—on an otherwise healthy specimen, it is impossible, in the theoretical sense that the flight of bumblebees is impossible, for an entire tree to be chlorotic and survive. Chlorosis is directly related to the health and well-being of the carotenoids—hydrocarbons which form the red, yellow, and orange pigments found in all photo-synthesizing cells. As unfamiliar as their name may be, most people can recognize them at a glance; it is carotenoids (from the same root as “carrot”) that are responsible for the brilliant fall colours in deciduous (leaf-bearing) trees. While these pigments are present throughout the year, they only become visible as the leaves die back in winter because they break down more slowly than the green chlorophylls that ordinarily dominate a leaf’s colour. In conifers, however, they play a more modest, supporting role; under normal circumstances this order of tree species seldom reveals its carotenoids in any obvious way—hence the nickname “evergreen.” Exceptions to this rule occur most often in the cases of death and disease.
Chlorosis can be caused by any number of things, including infertile soil, bug infestations, girdling (the typically fatal removal of a strip of bark all the way around the tree), and by too much, or too little, sun and/or water. But the golden spruce suffered from none of these afflictions. Not only was it big and old, which translates to “successful” in Sitka spruce terms, but it was growing in prime spruce habitat under ideal conditions. All the trees around it were healthy. Lacking external causes for chlorosis, all the evidence points to the condition originating within the tree itself. Rather than suffering from some pathology, the golden spruce probably had some inherent flaw, most likely one that affected the carotenoids. One of the several functions served by carotenoids is that of a barrier to ultraviolet light; in this capacity they act as a kind of natural sunscreen—a localized ozone layer—to protect the more UV-sensitive chlorophyll. In a plant where the carotenoids are not blocking UV rays as they should, the chlorophyll will break down and the plant will die. As long as such a tree remains shaded, its defective carotenoids won’t be tested, but as soon as they are exposed to direct sunshine, the flaw is revealed. As the undefended chlorophyll deteriorates, the green in the needles is lost, leaving only the faulty yellow carotenoids, which are unable to photosynthesize on their own. Under ordinary light conditions these yellow needles (which are still alive) will usually burn out and fall off. Chlorosis of the kind exhibited by the golden spruce bears some similarities to albinism, but a closer analogy can be found in xeroderma pigmentosum, the exceedingly rare skin disease that makes ultraviolet light fatal to humans. Though profoundly disruptive to a normal life, a person with this disease can protect himself by avoiding sunlight. However, a tree with this condition finds itself in a lethal Catch-22: in its instinctive quest for light it grows itself to death.
Somehow the golden spruce defied all logic by growing tall enough to be exposed to the sun’s full force without being killed in the process. Nor was it seriously stunted or delayed in any way; it was the same size as a normal tree of its age would have been under those growing conditions. And colouring wasn’t the only way in which the tree distinguished itself; as the golden spruce grew to maturity it revealed another peculiarity. Normal Sitka spruce trees are not only promiscuous—they will interbreed with any other spruce that will have them—they are also hermaphroditic, meaning each individual produces its own ovules as well as the pollen to fertilize them. But the golden spruce produced neither, making it, in effect, an asexual, infertile one-off; the chances of such an accident occurring again—successfully—are almost incalculably small.
Not only was the golden spruce sterile and a radically different colour than its normal counterparts, it also assumed a markedly different shape. As noted earlier, Sitka spruce are not particularly tidy trees; unlike many other conifer species, their natural tendency is toward frowsy asymmetry. The golden spruce, however, possessed a hedgelike density and an uncharacteristically conical shape. “It was perfect,” recalled a Haida silversmith and tree faller named Tom Greene. “It looked like a manicured tree.” An American forester and soil scientist named Edmond Packee who spent several years in Haida Gwaii and was familiar with the tree speculated that its compact, tapered appearance was a spontaneous adaptation intended to minimize the UV exposure that more typically wayward branches have t
o endure. Supporting this theory are photos of the golden spruce that show the dead and bleached remains of limbs that tried to venture out beyond the golden safety zone.
Plant physiologists, like doctors, have difficulty explaining strange behaviour in the absence of pathology. How does one make sense of a specimen that looks “sick” but isn’t? The only way botanists know to explain an oddity like this is with the term “mutation.” But, without analyzing a plant’s DNA, this is a vague explanation at best. A tree, like a person, can in theory be riddled with mutations that are invisible; as long as they don’t impact the individual’s appearance or health, they can go undetected. In an effort to get to the bottom of the mystery, a young forester named Grant Scott wrote his undergraduate thesis on the golden spruce. While he was enrolled in UBC’s school of forestry in the mid-sixties, he spent two summers cruising timber in Haida Gwaii. During that time he got to know the Yakoun Valley very well; not only did he acquaint himself with the golden spruce, but he found its biggest and best-known counterpart about fifteen kilometres upriver in a nearly identical position on the east bank. This Sitka spruce, while technically golden, is less uniformly coloured and more typically spruce-shaped; about thirty metres tall and a hundred years old, it is, one could say, more like what one would expect of a mutant under those circumstances. There are, in addition to this one, a couple of other “golden” spruces rumoured to live on the islands, but like the one Grant Scott found, none of them is as big, yellow, or uniquely shaped as the legendary tree that grew at the north end of the Yakoun.
Back in Vancouver, casting about for a thesis topic, Scott realized that what he really wanted to investigate was this extraordinary tree. But this would be a hard project to sell to his professors, most of whom were focused on the logging industry. Oscar Sziklai might have been a possible adviser if he hadn’t been too busy to trouble himself with undergraduates. It was at this point that a young professor from Yale named John Worrall entered the picture. Worrall was another Englishman, a contemporary of Bruce Macdonald’s, who had been hired by UBC to teach plant physiology. He actively encouraged Scott to pursue the mystery of the golden spruce and agreed to sponsor him. The goal of Scott’s thesis was to determine (a) why the golden spruce was golden, and (b) how the tree could survive with such a crippling disability. According to Scott’s research, it all comes down to chloroplasts, the tiny, subcellular bodies that do for plants what photo-voltaic cells do for solar-powered machinery. It is the disc-shaped chloroplasts that generate chlorophyll, thus enabling photosynthesis to take place. The needles on a tree are essentially vehicles for the chloroplasts, and they function much like solar panels; they are so well designed that chloroplasts will actually reorient themselves within a tree’s needles throughout the day in order to take full advantage of the sun. The flaw, believed Scott, lay in the proteins that bound the chloroplasts together. They functioned normally until they were exposed to sunlight, at which point they would mutate, causing the chloroplasts to become dangerously inefficient. Fortunately for the golden spruce, the needles that weren’t directly exposed kept their integrity and were able to live—even thrive—on reflected light.
The Golden Spruce Page 20
