Conservation of the Hollow Tree in ’s

HAROLD KALMAN AND LORNE WHITEHEAD

Vancouver’s Hollow Tree, a 1,000- The Hollow Tree impressive 50 feet (15 m). Its present truncated height is about 50 feet (15 m). year-old western red cedar and major Historic landscape features deserve Vancouver’s location at the southern tourist attraction, faced removal but recognition for both their natural and edge of the coastal cultural history; those of particular has been saved by a determined rainforest has made it home to some of value deserve conservation. The initial citizens’ group in an innovative the world’s tallest trees, including two failure to conserve a historic tree by the Douglas firs more than 400 feet tall, heritage-conservation project. Board of Parks and Recreation of the which were felled around 1900.3 West- City of Vancouver, British Columbia, ern red cedars grow stouter but less tall led to a conflict that polarized residents than Douglas firs. The Hollow Tree, but ultimately resulted in an intriguing which has lost its upper portion, likely and innovative heritage-conservation to wind or lightning, may have reached project with a successful resolution. a height of between 150 and 200 feet The Hollow Tree — formerly called (45 to 60 m).4 the Big Hollow Tree — is a western red The heart of the Hollow Tree began cedar (), perhaps 1,000 to decay centuries ago. Today the void, years old, whose core is mostly a hollow entered from the east side of the tree, is void. Although no longer living or grow- large enough to accommodate several ing, it is possibly the oldest tree in Stan- dozen people. Recent analysis of the tree ley Park, a spectacular 1,000-acre (400- rings (which survive only near the cir- hectare) peninsula that was reserved for cumference) by the Tree-Ring Labora- recreational use by Vancouver’s first city tory at the University of British Colum- council in 1886 (Fig. 1).1 bia indicate that the Hollow Tree was The western red cedar is the Provin- last alive around 1875; after then it cial tree of British Columbia, the “tree ceased to produce new growth rings.5 of life” of First Peoples in the Pacific The tree survived windstorms in 1934, Northwest, and the traditional material 1962 (Typhoon Freda), and 2006, which of choice for builders and carvers of the collectively destroyed some 15,000 trees . Lumber cut in Stanley Park.6 from western red cedar is easily split and ’s Dominion Entomologist, extremely resistant to rot and so is also inspecting the trees in Stanley Park, a favorite of contemporary builders. Of reported in 1914 that “the Cedar is very all trees in the region, western red cedar generally ‘stag-headed’ and hollow- grows the largest in diameter and often hearted.”7 Foresters recommended at the becomes hollow in later years. Only the time that the “stags,” or dead heads, be outside of the trunk contains living, cut so as to reduce the risk of their being growing cells — xylem and phloem — blown down in windstorms and to im- so the tree can continue to grow without prove the tree’s appearance and that the its inner core.2 Many western red cedars hollow cavities be filled with concrete to also have multiple tops (or spikes); when extend the time before the remainder of one top dies in a severe drought, a new the tree would fall to pieces. However, one will grow later. concrete was never inserted into the Vancouver’s Hollow Tree grew large. Hollow Tree (nor any other tree in Past descriptions, from a time when its Stanley Park). girth was larger than it is today (see be- It is generally believed that the Hol- Fig. 1. The Hollow Tree, with a touring car and low), claimed the circumference reached low Tree lost its upper portion at some its passengers, c. 1923. Photograph by Gowen 80 feet (25 m); today, it measures an Sutton Co. time before the arrival of Europeans in

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that “the famous old ‘Big Tree’ of Stan- turbed the silence of the Park, or before ley Park is to depart for all time...and be a human foot left its impress upon the shorn of the last ragged ends of its one- ground near where it stands.”13 The time grandeur.”10 The Park Board con- Hollow Tree became one of early Van- sidered stripping the tree of its signage couver’s premiere tourism attractions in response to a letter from banker W. and remained such for more than a M. Sellens, complaining that the tree century. As two old-timers told City was no more than “a ‘warty, unsymmet- Archivist Maj. J. S. Matthews in 1949, rical butt’ [that] should be called ‘the it was one of early Vancouver’s few hollow stump.’” (Technically the tree is points of interest: “nowhere much to a “snag” and not a stump, and the go; nothing much to see. So visitors “wart” is a large burl to the right of the were taken for a drive around Stanley opening.) An editorial in the Vancouver Park, and shown the ‘Big Hollow Tree.” Sun at the time suggested that “the It was one of the sights no visitor was Hollow Tree has gone to its fathers, to permitted to miss.”14 Major Matthews become one of the legends of time.”11 himself was quoted as saying: “To come The no-longer-living tree certainly had to Vancouver and not see ‘The Big Hol- reached one of the last stages of its low Tree’ was like eating an egg with- 15 Fig. 2. The Hollow Tree sketched as an intact natural progression. As is common with out salt.” tree with foliage, 1932. Dominion Map and Blue old trees, it was “nursing” two young The Hollow Tree was highly accessi- Print Company, , Map hemlocks, one growing out of the burl ble and remains so today, possibly a 130100. on the eastern side and the other out of unique example of one of the world’s the roots on the western side. largest trees being located within a few the second half of the nineteenth cen- In 1965-1966, just after Typhoon feet of an urban road. Stanley Park’s tury, although this loss may have oc- Freda wreaked havoc on Stanley Park, popular circular roadway, Park Drive, curred as recently as 1934. No known the Park Board made a number of inter- was laid out in 1889 so as to pass along- early images show the upper portion — ventions to protect the Hollow Tree. It side the tree. Residents and visitors alike with or without branches — and pho- built a curb around the base of the tree could not resist being photographed tographs of the truncated top appear to discourage motorists from driving inside the tree. A favorite pastime was only in the second half of the twentieth into it and paved the adjacent parking backing one’s car (or carriage) into the century. An image on a 1932 map of area. About 2 feet of loose fill was tree and recording it on film. Between Stanley Park shows the Hollow Tree placed around the base of the tree, 1908 and 1941 the Park Board encour- with its upper portion and foliage intact raising the grade to the top of the curb. aged the practice by retaining an “offi- and with its hollow core and identifies it This action had the unfortunate effect of cial” photographer to set up shop beside as Large Hollow Tree (Fig. 2).8 The retaining rainwater in the fill, in contrast the tree. Countless images showing question remains whether this sketch to the naturally well-draining hardpan people outside, inside, or climbing on was intended to represent actual condi- below, and probably significantly accel- tions or whether the foliage was simply erated the deterioration of the tree’s a conventional way to draw a tree. If the lower structure. Other interventions at top were indeed intact in 1932, it would that time included adding metal braces, most likely have been blown over in the cables, and plates as reinforcements and vicious windstorm of October 21, 1934, removing another 8 feet from the top of an extreme weather event that toppled the tree for perceived safety reasons (Fig. an estimated 2,000 trees in the park. 3).12 The Vancouver Board of Parks and Recreation resolved to remove the debris An Early Tourism Attraction and restore Stanley Park to an undis- turbed appearance, but cleanup was Europeans settled in Vancouver in the slow. A federal-municipal funding agree- second half of the nineteenth century, ment was finally reached in November just as the Hollow Tree stopped grow- 1935, and the restoration work fol- ing. The tree attracted attention among lowed.9 early Vancouverites for its age, its size, Within a few months the first known and the large void at its core. The tree references to the Hollow Tree being was seen as a link to the romantic, dis- topless appeared. In January 1936 news- tant past in a city with a very young papers reported that “the famous ‘Big history. One early writer, ignoring mil- Tree’ or ‘Hollow Tree’ on the Stanley lennia of First Nations’ presence, specu- lated that “The Big Tree may have Fig. 3. The Hollow Tree being topped, 1966. Park roadway...is going to lose some of Note the two young hemlocks growing out of it. what is left of its splintered top” and flourished before a human voice dis- City of Vancouver Archives, 392 1012. CONSERVATION OF THE HOLLOW TREE IN VANCOUVER’S STANLEY PARK 5

ing trees in the Pacific Northwest.20 The while providing some educational value, tree has added public value for being a the report itself had major flaws. The uniquely accessible historic place. report failed to acknowledge the tree’s cultural values or its formal municipal The Hollow Tree in Crisis and federal heritage recognition. It also overstated the engineering challenge of As the tree aged, its natural structural- stabilizing the tree and claimed that the support systems weakened. This condi- public favored removing the tree, al- tion was probably exacerbated by the though no survey of public opinion had loose fill placed around the base in been carried out. Fig. 4. The Hollow Tree, with a circus elephant 1965. The result was considerable de- Staff presented the report to the inside, lifting a woman off the ground, c. 1925. terioration of the underground structure Photograph by Gowen Sutton Co. elected Park Commissioners on March of the Hollow Tree. It may have been 31, 2008, with little advance publicity this intervention that caused the tree to and virtually no public debate.22 A few the Hollow Tree, often sitting in their tilt eastward and slowly force the open citizens identifying themselves as the vehicles, have survived in archival col- (east) side to descend toward the Friends of the Hollow Tree argued for a lections and on postcards (Fig. 1). The ground. Comparison of photographs more balanced study before irreversible many celebrity visitors to be photo- taken around 1920 and 1980 shows action was taken, but the Commission- graphed included the Governor General, that approximately 3 feet (1 meter) of ers ignored the discussion and unani- the Duke of Devonshire, with his en- the trunk on the east side has disap- mously resolved “that the Board ap- tourage; another was a circus elephant peared from the bottom and that the prove the taking down of the Hollow (Fig. 4). diameter of the tree at the base is less Tree as it has become a public safety The Hollow Tree began to lose its than it was previously (Fig. 5). concern.”23 superstar status in the second half of the In December 2006 a storm lashed The Friends turned to the Vancouver twentieth century, as Vancouver devel- Stanley Park with hurricane-force winds, Heritage Commission, the body ap- oped many other tourism attractions leveling about 100 acres (40 hectares) of pointed to advise the city council on and visitors began to seek experiences forest and toppling an estimated 10,000 heritage matters. The commission re- that were more active. Nevertheless, the 21 mature trees. In the subsequent inspec- quested that the Park Board follow tree’s established role as a cultural at- tion of damage to the park, it was found established cultural-resource-manage- traction earned it formal recognition as that the Hollow Tree was leaning about ment principles, but the Park Board a significant historic place. It is listed as 12 degrees out of plumb. The Park rejected the appeal and upheld its origi- a landscape-resource “monument” on Board blamed the storm, but in fact, as nal resolution. the Vancouver Heritage Register.16 The Figure 5 demonstrates, the tree had been In the weeks ahead, as workers were Government of Canada has designated leaning for some time and was remark- preparing the Hollow Tree for being cut Stanley Park a National Historic Site, able for having survived the winds while down, several Park Commissioners and the Hollow Tree is identified as a so many younger trees had been felled. began to hear the reasoning in the argu- “tree with cultural significance” in the Stanley Park’s maintenance staff ments for the tree’s conservation, as well Commemorative Integrity Statement recognized that the Hollow Tree posed a as the growing negative public reaction prepared by Parks Canada.17 The endur- hazard, as it was unstable and could to their stance. Sensitive to grassroots ing value attached to the tree was even collapse at any time. In November 2007 feelings with an election approaching, evident in a promotional animated video a safety fence was erected around the two commissioners convinced their for the Vancouver 2010 Winter Olym- tree, and a structural-engineering firm colleagues to reverse their stance. Conse- pics, in which two Olympic mascots was retained to examine options for its quently, on July 7, 2008, the Park Board court each other at the base of the Hol- stabilization. agreed to delay taking down the tree for low Tree.18 The Park Board staff report of March 150 days to allow the community group The Hollow Tree has considerable 2008 presented two options. The first to undertake an engineering report con- heritage value as a cultural landscape — was an expensive stabilization of the firming that the tree could be “stabilized a landscape that has been modified by, Hollow Tree in its tilted state, support- and made safe in an upright position on and reveals evidence of, human activity ing it on four hefty steel braces secured its current site” but also asserting “that — and as a monument of nature. “Mon- in concrete pedestals, with the tree the Board will not provide any funds for uments of nature” is a developing cate- strapped in steel bands, its base pro- the retention of the Hollow Tree in its gory in the ICOMOS lexicon, consisting tected with a concrete curb, and its peak present position.”24 of prominent natural features that carry sheltered by a large, hovering, circular The community group was incorpo- important cultural dimensions.19 The transparent cover. The other proposed rated as the Stanley Park Hollow Tree Hollow Tree has cultural-heritage value option was to cut down the tree, split it Conservation Society. The society imme- for having been perhaps the most popu- into two, and position it horizontally on diately set out to raise funds, retain lar attraction in Vancouver, and it has a nearby gravel pad, planting a young structural engineers (the Cascade Engi- natural-heritage value in its being repre- western red cedar near its head. While neering Group of Canmore, Alberta, sentative of the oldest and largest surviv- the latter proposal would have cost little specialists in wood structures), and use 6 APT BULLETIN: JOURNAL OF PRESERVATION TECHNOLOGY / 42:4, 2011

sound and as dense as newly harvested western red cedar. However, the form of the Hollow Tree was found to consist of seven very strong individual vertical segments that had comparatively weak connections to one another. Further- more, the wood within 20 inches (50 cm) of ground level was largely eroded, and the roots below ground level were essentially nonexistent. Finally, large sections of the wood contained voids, comprising about 20 percent of the volume, although they did not substan- tially reduce the overall integrity of Fig. 5. Photographs of the east side of the Hollow Tree, c. 1920 and c. 1980. The horizontal lines structure. In essence, the Hollow Tree match the same features in the two photos. The lost material at the bottom required shifting the right was somewhat like the leaning tower of photograph upward by the equivalent of about 3 feet (1 m). Composite photograph by Lorne White- Pisa — it was a fairly solid object on a head. foundation that was slowly and contin- uously giving way. As the tilting pro- the group’s own skills and ingenuity to the advantage of presenting more gressed, the resultant torque from the stabilize the Hollow Tree.25 clearly the keys issues and main stages overhang of the center of mass was Relations between the Conservation of the project. growing, and hence the process was Society and the Park Board improved accelerating. At some point — possibly after November 2008, when the election Research to Determine the Nature of very soon — the Hollow Tree would brought in a new, more empathetic the Structure collapse. group of Park Commissioners. One Careful dimensional measurements (who subsequently became the Board The condition assessment of the Hollow were also taken to allow solid modeling chair) had appealed to the previous Park Tree was performed through a variety of the structure. Small samples of wood Board to save the tree. In time the Soci- of methods. One technique used a re- were taken to measure its density and ety would complete the righting and sistograph, which measures wood den- strength. The bending strength of the stabilization of the tree and hand the sity along boreholes that are so small wood was measured at the Faculty of tree back to the Park Board for land- (1/16-inch diameter) that they essentially Forestry at the University of British scaping and interpretation. seal themselves after measurement. The resultant data established that the mate- Columbia, using a hydraulic press that rial of the Hollow Tree was primarily applies a gradually increasing displace- Conserving the Hollow Tree The project posed a complex conserva- tion challenge. Ideally a conservation project proceeds in four distinct and consecutive stages — research, design, fundraising, and implementation. In this case, this sequence was impossible to follow. Some of the most important re- search information could not be ob- tained until implementation was under- way, so it was necessary to take an iterative approach that blended the stages in a manner that required careful judgment and entailed taking calculated risks, while ensuring life safety at all times. Such a complex path is never desirable, but in this case, due to the short time frame required by the Park Board, it was unavoidable. The follow- ing is a somewhat simplified account that describes the work as if it had progressed in the ideal order of re- search, design, fundraising and imple- Fig. 6. This 2008 photograph shows the unstabilized position of the Hollow Tree, and the lines and mentation. Although this omits some of arrows show the movement of the tree that resulted from the test displacement. Image by Lorne the iterative aspects of the project, it has Whitehead. CONSERVATION OF THE HOLLOW TREE IN VANCOUVER’S STANLEY PARK 7 ment to the center of a 16-inch-long sample with a 1-inch-by-1-inch cross- section, with the grain aligned with the long dimension. The bending resistance was observed with a load cell until the point of failure. It was somewhat sur- prising to find that the strength of the ancient tree was slightly higher than that of typical western red cedar harvested and marketed today. Interestingly, the wood’s density, relative to water, was found to be 0.76, dropping to 0.37 after kiln-drying. This result is surprising because the values for green western red cedar are generally considered to be about 0.43, dropping to about 0.32 when kiln-dried. Apparently the water content of the wood in living western red cedar trees stays considerably below complete saturation, thereby maximiz- Fig. 7. Sections showing the micropiles, concrete pile cap, and major support frame, 2009. Drawing ing their strength-to-weight ratio. This by Cascade Engineering. was an important observation, since it showed the Hollow Tree was highly multidisciplinary deliberation, the team ments were a foundation system, a waterlogged, and therefore its weight devised a practical design for stabilizing frame system for supporting the tree, an could be considerably reduced by plac- the Hollow Tree. attachment system between the founda- ing a rain barrier over the exposed end tion and the frame, and an attachment grain at the top. The resultant drying Conservation Approach and Design system between the frame and the wood. effect was also expected to slow further Foundation. The foundation system decay. The Stanley Park Hollow Tree Conser- vation Society prepared a conservation design called for 14 steel foundation In a final test, a hydraulic jack system micropiles, each grouted to a depth of applied pressure to a temporary support plan that set out the principles for the interventions to the Hollow Tree. It 15 feet (4.5 m) in the glacial-till hard- member, to achieve a displacement of pan beneath the Hollow Tree. In other about 6 inches (15 cm) at the midpoint declared the overall goal to be “To safely retain the Stanley Park Hollow circumstances, a simpler alternative of the structure. Digital photography could have been to form a deep and and computer-analysis techniques accu- Tree, in situ, upright and with its ap- pearance substantially unchanged, as a broad reinforced-concrete foundation rately determined the movement of whose weight alone could provide suf- various points on the tree. It was found significant lasting heritage landmark in Vancouver.” The plan stipulated that all ficient stability against wind and earth- that the tree would preferentially rotate, quakes. However, in this situation it as a single coherent object, around a work should follow best practices in both heritage conservation and engi- was not possible to remove the Hollow horizontal axis near ground level and Tree to enable such major excavation. centered beneath it. Figure 6 shows the neering. It recommended that the con- servation approach should be the res- In contrast, because of the Hollow original position of the tree, and the Tree’s open interior, it would be possi- superimposed lines and arrows show the toration of the tree to its appearance in the early twentieth century, when it was ble to employ handheld drills inside the movement of the tree that resulted from tree in order to create the required holes the test displacement. The only excep- a major tourist attraction. It also deter- mined that all work should follow the into which the micropiles could be tion to this rotation was at the leftmost grouted to form, effectively, artificial point, at the top of the burl, which did Standards and Guidelines for the Con- 26 roots. Topsoil was to be removed in a not move, showing that although the servation of Historic Places in Canada. Working according to these princi- circular area around the tree approxi- burl was adjacent to the tree, it was not mately 40 feet (12 m) in diameter, but structurally connected to it. The test also ples, a set of structural drawings was prepared by the engineers (Fig. 7). The to a depth of only 1 foot 8 inches (50 determined that the required force to cm), and then replaced with a steel- cause such movement was less than design system comprised four basic ele- ments, none of which was unusual in reinforced concrete pile cap that would 11.25 tons (100,000 Newtons), which is encapsulate the top portions of the well within the capacity of available and of itself but which together com- prised a unique solution to a problem micropiles, each of which was to be large cranes. This finding meant that topped with nut-locked connection returning the Hollow Tree to a vertical that, to our knowledge, had not previ- ously been encountered in this form in plates. The strength of this foundation orientation was feasible. design would exceed the anticipated Based on this finding, further engi- either professional engineering or her- itage-conservation practice. These ele- loads from possible weather-related and neering calculations, and considerable seismic events by approximately a fac- 8 APT BULLETIN: JOURNAL OF PRESERVATION TECHNOLOGY / 42:4, 2011

bridging element. These bolts would be embedded in a long-life epoxy glue deposited in oversized bore holes to provide an enlarged bearing area and bond to the wood of the Hollow Tree. These two attachment techniques were known to have different minor advan- tages and disadvantages and a combina- tion of the two was considered optimal. When attaching steel components to slender, tall trees, one important area of concern is the effect of the natural swaying of the tree in the wind. This is not an issue for the Hollow Tree, since it is, by comparison, wide and short. In any event, the stiffness of the steel and the connections to the tree would pre- vent any movement at the connection points.

Fundraising One of the greatest challenges faced by Fig. 8. The Hollow Tree supported by temporary Fig. 9. The Hollow Tree being raised upright, braces, July 2008. Photograph by Harold June 11, 2009. Photograph by Amy Cameron. the Conservation Society was that the Kalman. Park Board was unwilling to pay for the work. The society was therefore re- tor of 10. Although frost heave is not of the tubular frame elements to the pile quired to undertake its own fundraising an issue in Vancouver, another advan- cap of the foundation was very strong efforts. Shortly after this condition was tage of this design is that the micropiles and simple but also subtle. The tubes agreed to, the recession of 2008 com- would provide stability against frost would be put in place and would extend menced, and fundraising became pro- heave in essentially any climate. to the bottom of the excavation region foundly more difficult. Fortunately, before the reinforced concrete of the although cash donations had essentially Frame. For the frame, tubular, black- foundation pile cap was poured; they stalled, suppliers supported the project painted, hollow structural-steel ele- would be threaded with steel rebar to by assisting with substantial in-kind ments were to be placed next to the ensure an extremely solid connection to inside walls of the Hollow Tree, each the foundation system. (Although in- with an inclination from the vertical trinsically simple, this plan did compli- matching that of the inside surface of cate implementation by constraining the the structure (about 6 degrees). This order of operations.) simple design concept had the benefit of being hardly noticeable to casual ob- Attachment of the frame to the Hollow servers, yet clearly distinguishable from Tree. Two different approaches were the tree with a close look, consistent devised for attaching the frame to the with best practice in conservation. The wood. The first involved threading system was also adaptable to the need 1-inch (2.5-cm)-diameter galvanized of the complex structure at hand threaded rods through the wood from through the use of two different tube outside the Hollow Tree structure and diameters. Three 6-inch (15-cm)-diame- the adjacent steel tube, with matching ter tubes were planned to provide the washers and locked nuts to ensure main structural support, rising up to a strong positive attachment and friction. height of 16 feet (5 m) within the struc- The second involved spanning the tops ture, and an additional seven 3-inch of the large steel tubes with a welded 6- (7.5-cm)-diameter tubes would rise to a inch (15-cm)-square, hollow structural- height of 6 feet 6 inches (2 m) adjacent steel bridging element, which would to smaller sections of the Hollow Tree provide added mechanical stability to that required additional stabilization the frame. Twenty 1-inch (2.5-cm)- near ground level. diameter galvanized connection bolts, Fig. 10. The internal support frame, showing the each penetrating the wood of the Hol- tubular-steel uprights and the horizontal bridging Attachment of the frame to the foun- low Tree, would be placed along this elements, August 2011. Photograph by Harold dation. The design for the attachment Kalman. CONSERVATION OF THE HOLLOW TREE IN VANCOUVER’S STANLEY PARK 9

to maintain this support, no excavation hide the support elements but that made was undertaken beneath these support them unobtrusive in this setting (Fig. points. However, the entire remaining 10). The support frame is painted black area within the circle was excavated, and is visually lost in the shadows; both to make room for the foundation however, it is fully evident upon enter- pile cap and to clear the way for the ing the tree. Ironically, one of the great- rotation of the tree that would be re- est challenges was in drilling the long quired to straighten it. bolt holes through the wood — the Straightening. A large construction wood was much stronger and harder to crane was used to apply an upward drill than anticipated. stabilizing force to the east side of the Pouring the pile cap. Although critically Hollow Tree, which enabled the timber important, the last step was also the Fig. 11. A portion of the concrete pile cap, shortly after pouring, October 2009. Photograph supports to be temporarily removed. least problematic: reinforcing steel was by Lorne Whitehead. The crane then pulled it up further, and, installed in the excavated region, also as hoped and expected, the Hollow Tree threading the tubular-steel support ele- donations of goods and services. In the achieved a vertical orientation (Fig. 9). ments, and the concrete was poured, end, the work was achieved with ap- The timber supports were lengthened so resulting in a smooth surface just below proximately Can$60,000 in cash dona- that they could reach their attachment the level of the adjacent ground (Fig. 11). tions and Can$120,000 in in-kind points and were reinstalled to again The only difficulty was that the con- donations of goods and services. temporarily stabilize the tree. The crane fined geometry of the hollow tree and was then removed. its surroundings limited access of the The two “nursing” hemlocks were concrete truck and required very labor- Implementation of the Conservation removed, in part because their growth intensive placement of the concrete. Design was slowly destroying the Hollow Tree, The outcome of the conservation The implementation process took place and also because their removal was process is a clean appearance that very in six steps: consistent with the conservation plan, much resembles the appearance of the which called for restoration to the ap- Hollow Tree from decades earlier (Fig. Temporary support. We now know — pearance in the early twentieth century, 12). but did not know at the onset of work before they began to grow. In addition, — that the Hollow Tree was very close hemlock has a comparatively short life to falling over. Fortunately, the very first Interpreting and Landscaping the span, and the two trees would soon step in the conservation process was to Hollow Tree have begun to rot, causing damage to install two 33-foot (10-m)-long, 1-foot the Hollow Tree in the process. A sheet- The project includes a program of in- (30-cm)-diameter temporary timber metal flashing was inserted at the top of terpretation to tell the public the princi- braces that spanned the installed foun- the tree to prevent saturation with rain- pal stories about the tree. The Stanley dation blocks to points approximately water. Park Hollow Tree Conservation Society 16 feet (5m) above ground level, effec- tively forming a large tripod that would Installing micropiles. The installation of be stable, even if all torsion support the micropile foundation was compli- from the ground were to fail (Fig. 8). cated by geometrical constraints within the structure of the Hollow Tree. Addi- Excavation. Because of the sensitivity of tionally, there were difficulties with the project and the confined geometry, a excess grout, which later had to be painstaking manual process was neces- removed by jack-hammering in order sary to remove the top 1 foot 8 inches for the reinforced-concrete pile cap to (50 cm) of soil to make way for the be installed. A test of a nearby micro- installation of the micropile and rein- pile established a very good connection, forced-pile-cap foundation system. Dur- with both high tensile and compressive ing this process, valuable structural in- strength, into the glacial-till-hardpan formation was also obtained, which substrate. informed the design process in the iterative manner mentioned earlier. As Installing the support frame. The instal- careful excavation continued, the rea- lation of the tubular-steel frame ele- son for the north-south axis of available ments was done simultaneously with rotation was identified: the entire their attachment to the interior of the weight of the Hollow Tree was sup- Hollow Tree, using the design methods ported on two main roots passing into described earlier. The installation pro- the ground, located on the north and cess involved removal of small amounts Fig. 12. The Hollow Tree after conservation and south sides of the tree, on approxi- of wood to allow a snug fit to the inte- landscaping, August 2011. Photograph by mately its east-west center line. In order rior in a manner that did not attempt to Harold Kalman. 10 APT BULLETIN: JOURNAL OF PRESERVATION TECHNOLOGY / 42:4, 2011

effort and dedication from a diverse group of skilled participants with a broad range of complementary knowl- edge. Most had not previously known one another and had come together because of the importance of the cause to them. The group had the courage to reject its own interim designs that did not meet the objectives and to continu- ally search for the best way to achieve the project. It is only natural to ask whether there are lessons to be learned, beyond the creative engineering design and applica- tion of construction and conservation techniques that enabled success. We Fig. 13. One of the four interpretive panels, 2011. Design by Christina Lazar-Schuler. suggest that there are several. First, it was troubling to observe that produced an interpretation plan.27 Two The interpretation design is part of a a well-intentioned Park Board could, at complementary media have been plan- larger landscape plan. The landscape first, remain intransigent when presented ned. The first consists of interpretive plan, which has been carried out, in- with evidence that its initial decision panels in front of the hollow opening; cluded enlarging the paved parking area, was based on incorrect and incomplete the second is the pavement within and devising an improved traffic-circulation information. The only reason appeared in front of the tree, which will provide plan, rebuilding the curbs, placing a to be an all-too-human reluctance to the chronology of the Hollow Tree.28 split-rail fence along Park Drive, and admit to an innocent, unintentional The principal stories associated with providing the site with a new drainage error. From that perspective, it was the Hollow Tree are told in four panels system constructed across the roadway. encouraging later when, in the face of in front of the tree. Three panels provide The soft landscaping includes planting growing public concern, Park Board the narrative: they address natural his- the area on which the tree stands with found the courage to say, “We made a tory, recent history, and deliberations, grass and low ground cover using in- mistake; let’s fix it.” the last offering both sides of the preser- digenous plant materials. A young west- Second, despite Park Board’s reversal, vation argument. Each has text, quota- ern red cedar was planted south of the the Hollow Tree took on a symbolic tions, and illustrations (Fig. 13). The Hollow Tree. As it grows it will provide significance in the eyes of some people fourth panel provides acknowledgments, a backdrop to the Hollow Tree and with strong nature-centric beliefs, who listing the many people and businesses ultimately will replace it. As planned believed that any structural intervention who donated money, goods, and ser- from the outset, the landscape work was was inappropriate in Stanley Park. In vices. carried out and paid for by the Park the end, a subtle but important principle A wedge-shaped plaza in front of the Board.30 of a democratic society triumphed: a opening of the Hollow Tree, as well as healthy democracy is not one in which the majority of people like every single the ground within the tree, will record Conclusion 18 key events that directly affected the thing, but rather a place where the tree, from its germination a millennium Clearly the most important outcome of majority of people allow the simultane- ago until its conservation, all related by this endeavor has been the conservation ous expression of a many views, any one the Hollow Tree in the first person.29 of a significant natural and cultural of which may appeal only to a minority. The chronology will be treated as a resource in a manner that follows both Third, a lesson was found in the series of concentric, undulating curves best conservation and best engineering success of the fundraising, which was reminiscent of tree rings, formed by practices, satisfies the majority of inter- made much more difficult by the eco- inscribed basalt blocks set into the ested parties, and is safe, durable and nomic recession. On the one hand, the concrete pavement. The tree’s birth is affordable. The Park Board had dis- wisdom of saving the Hollow Tree was marked at its center, and the present is missed the task as being impossible to readily apparent. On the scale of funds at the circumference, with the distance achieve, based on one design that had routinely applied to such stewardship between events roughly representing the been prepared without any investigation purposes and given the significance of time elapsed between them on a loga- of the physical conditions and without the project, the amount required was rithmic scale, so that modern events are an understanding of conservation objec- quite small. Yet to a world fraught with not squeezed together. Some bands are tives. What began as a political chal- serious economic problems, a conser- wider than others for emphasis (such as lenge became a technical one. Success vation effort could be derided as mis- natural disasters that the tree survived) was by no means assured and was guided. How reaffirming it was, in this and visual interest. achieved only through extraordinary setting, to have a great many committed citizens, professionals, and corporations CONSERVATION OF THE HOLLOW TREE IN VANCOUVER’S STANLEY PARK 11 step forward and offer their support to 6. Sean Kheraj, “Restoring Nature: Ecology, 21. See Vancouver Board of Parks and Recre- make this work. Memory, and the Storm History of Vancouver’s ation, Stanley Park Restoration, Dec. 2007, Stanley Park,” Canadian Historical Review 88, http://vancouver.ca/parks/parks/stanley/ no. 4 (Dec. 2007): 590–608. restoration/pdf/RestorationProgressReport HAROLD D. KALMAN, PhD, LLD, CAHP, is 7. Memorandum by Dominion Entomologist, _2007_WEB.pdf. This progress report makes a principal of Commonwealth Historic Re- no mention of the Hollow Tree. See also http:// source Management Limited and honorary Vancouver, B.C., 1914, City of Vancouver Archives, quoted in Stanley, 29. vancouver.ca/parks/parks/stanley/restoration professor of architectural conservation at Hong /index.htm for a summary of the storm and the Kong University. He is a heritage professional 8. Map of the City of Vancouver, British Co- work. and an architectural historian, and a former lumbia (Vancouver: Dominion Map and Blue member of the Board of APT. He lives in Print Company, 1932), Vancouver Public 22. Vancouver Board of Parks and Recreation, Vancouver and can be reached at kalman@ Library, Map 130100. Staff Report, Mar. 31, 2008; the engineering chrml.com report appended to it was David Nairne and 9. Kheraj, 590, 597, 598. Associates, “Structural Assessment of the LORNE A. WHITEHEAD, PhD, PEng, is a 10. Vancouver Sun, Jan. 24, 1936, pp. 3–4; see Hollow Tree in Stanley Park,” March 2008. professor in the department of physics and also Vancouver News Herald, Jan. 24, 1936, p. 23. Park Board minutes, March 31, 2008. astronomy at the University of British Colum- 8. 24. Park Board minutes, July 7, 2008. bia, where he holds the NSERC/3M chair in 11. Quoted in Stanley, 29. applied physics. He holds more than 100 25. The board of directors comprised Univer- patents, primarily in the fields of illuminating 12. Stanley, 29. Unidentified clippings, proba- sity of British Columbia physicist and engineer engineering and information display, and has bly from Vancouver Sun or Province, Mar. 24 Lorne Whitehead, heritage-conservation con- commercialized this work both by licensing and Mar. 30, 1965. sultant Harold Kalman, teacher and historian existing companies and launching new ones. 13. Catherine Mae MacLennan, Rambling Bruce Macdonald, lawyer Edward Lewin, He can be reached at [email protected]. Round Stanley Park (Toronto: Ryerson Press, historian Meg Stanley, and engineer Jon Scott. 1935), 40, cited in Stanley. Construction management was by engineer Doug Campbell and tree expertise by arborist Acknowledgements 14. Memorandum by Maj. J. S. Matthews, Julian Dunster. Many other skilled profession- 1949, City of Vancouver Archives, Stanley als volunteered abundant service and labor. The authors thank Bruce Macdonald, who Park, G.N. 104 N. P.11. Major Matthews, an Construction services were carried out by helped with the preparation of this article. untrained but immensely enthusiastic archiv- Macdonald & Lawrence Timber Framing Ltd. ist/collector, did not document material that he and several other firms. collected. Notes 26. Stanley Park Hollow Tree Conservation 15. Quoted in Stanley, 28. Society, Conservation Plan for Stanley Park’s 1. Meg Stanley, “Stanley Park’s Big Hollow 16. City of Vancouver, Vancouver Heritage Hollow Tree, Oct. 2008; http://www.savethe Tree,” The Beaver 77, no. 4 (Aug.-Sept. 1997): Register, rev. April 2006, p. 32, http:// hollowtree.com/id2.html. 27–29. vancouver.ca/commsvcs/Guidelines/V001.pdf. 27. Harold Kalman et al., Interpretation Plan 2. Nancy J. Turner, School of Environmental Registration identifies historic places but does for the Hollow Tree, Vancouver, 2010, http:// Studies, University of Victoria, communication not provide protection. www.savethehollowtree.com/id2.html. to Harold Kalman, Aug. 10, 2010. Additional 17. Parks Canada, Stanley Park National information from Turner, “‘Trees for Life’: The 28. The landscape and interpretation design Historic Site of Canada: Commemorative Cultural Roles of Western Red Cedar and Yel- were provided pro bono by Phillips Farevaag Integrity Statement, 2002, p. 17, http://www low Cedar for First Peoples of Northwestern Smallenberg, landscape architects and planners. .stanleyparkecology.ca/programs/conservation North America,” presentation at First Interna- The graphic design was produced pro bono by /research/CommemorativeIntegrityStatement tional Cedar Symposium, Univ. of Victoria, Christina Lazar-Schuler, graphic artist. 2002.pdf. 2010. 29. Robin Inglis kindly suggested the first- 18. At the time of writing, the video could be 3. Bruce Macdonald, “The Tallest Trees in the person voice. viewed at http://www.youtube.com/watch?v World Grew in Vancouver?” unpublished essay, =lnSncdPP8VY. It had been available on the 30. The installation of the interpretative pave- 2009. Robert Van Pelt, author of Forest Giants web site of the Vancouver Olympic Organizing ment remained incomplete at the time of of the Pacific Coast (: Univ. of Washing- Committee (VANOC), which has been removed writing this article. ton Press, 2001), 34, 46-47, lists the largest from the Internet. The image includes an inter- Douglas fir (by volume) as being British Co- pretive panel to the left of the tree. lumbia’s Red Creek Tree, and British Colum- bia’s Cheewhat Lake Cedar as being the second 19. The theme of the International Day for The APT Bulletin is published by the largest and second tallest red cedar. It is impos- Monuments and Sites in April 2007 was Cul- Association of Preservation Technol- sible to know what stood before many of the tural Landscapes and Monuments of Nature; ogy International, an interdisciplinary old-growth trees in the Northwest — and see the introduction by Dinu Bumbaru, Secre- organization dedicated to the prac- virtually all in urban areas — were logged in tary General of ICOMOS, at http://www tical application of the principles and the late nineteenth century. .international.icomos.org/18thapril/2007/18th techniques necessary for the care and wise use of april2007-4.htm. Resolution 28 of ICOMOS’s the built environment. A subscription to the 4. The presumed height is extrapolated from 16th General Assembly in Québec in 2008 Bulletin and free online access to past articles are other western red cedars of similar circumfer- member benefits. For more information, visit directed that the theme of monuments of nature ence and age; the tallest recorded by Van Pelt is www.apti.org. should be explored further; Dinu Bumbaru to 195 feet tall. Harold Kalman, May 19, 2010. 5. Lori D. Daniels, Tree-Ring Laboratory, Dept. 20. Van Pelt, Forest Giants of the Pacific Coast, of Geography, Univ. of British Columbia, 30–31. e-mail to Bruce Macdonald, Aug. 16, 2010.