Documenting a Heritage Tree: Digital Preservation of Calgary’s Stampede Elm

Editor’s note: Digital documentation of the Stampede Elm was conducted by Dr. Peter Dawson and Madisen Hvidberg from the Department of Anthropology and Archaeology at the University of Calgary, in partnership with the City of Calgary. A digital archive post of the Stampede Elm, created by University of Calgary archaeology PhD students Christina Robinson and Madisen Hvidberg, can be found here.

Written by: Madisen Hvidberg, MA

When asked to think of something that is “heritage,” what comes to mind? Most likely you will think of things like grand monuments, temples and old buildings. Maybe you know some specific UNESCO World Heritage Sites, or you think of archaeological heritage like excavations and artifacts. No matter what you think of, I would guess that it is probably unlikely that your first thought was…a tree.

Biological and living heritage sites can also be testaments to history. Gardens, parks and trees can represent past initiatives for beautification or utilitarian uses of the plants, and can be just as much of a part of the heritage of a place as buildings or objects. In North America much of the biological heritage within major cities is related to European settler aesthetic for planted trees and gardens, a desire to add more wind breaks in open areas, and the City Beautiful Movement of the 1890s and 1900s. The City Beautiful Movement was a reform philosophy popular in the early development of North American cities, which suggested beautification would promote social harmony and as such led to the establishment of many parks, gardens and tree-lined boulevards.

Calgary’s History of Trees

Calgary was no exception to the influences of this movement, which were largely brought to the city by William Pearce who envisioned Calgary as a “city of trees”. Pearce was a surveyor, engineer and statistician, and when appointed as an inspector for the Dominion Land Agencies in 1884, he used his position to reserve land along the north side of the Bow River. That land today is Calgary’s landmark boulevard Memorial Drive. Pearce reserved other lands for parks and started a local tree farm to find different types of trees that could grow in Calgary’s climate, with the goal of encouraging Calgarians to plant their own gardens and groves.

William Pearce, ca 1880. Source: Glenbow Archives, NA-339-1.

Pearce was not the only person dedicated to vegetative beauty of the city. In 1913, William Reader became Calgary’s third Superintendent of Parks and Cemeteries. Until his tenure ended in 1942, Reader dedicated himself to public improvement projects that planted trees, created boulevards and beautified the city. During that time, Reader created numerous streetscapes that have since been added to Calgary’s Inventory of Historic Resources.

An American Elm Tree in Calgary

Resulting from these types of early efforts, Calgary today has 73 identified locations of historic trees. One of the more famous and cherished trees in the city is the Victoria Park American elm tree, also known as the Stampede Elm. American elms (Ulmus americana) were exceptionally popular trees during the City Beautiful Movement. Unfortunately, due to the susceptibility of these trees to Dutch elm disease, they are no longer recommended as species for urban forests and are now infrequently planted within urban cityscapes.

The Stampede Elm is only one of five of this species listed on the historic tree inventory for the City of Calgary. It is located in the Northwest parking lot of the Stampede Grounds near the location of Calgary’s first hospital, now the site of the Rundle Ruins. No one knows how old the tree is except that it was likely planted in the early 1900s. At this time, the area was residential and it is likely that the tree may have been planted in someone’s yard.

The “Stampede Elm” one of Calgary’s American elm heritage trees, located on the northern side of the Calgary Stampede grounds. Source: Capture2Preserv project.

No matter who planted it, the Stampede Elm has preexisted even the notion of the infamous Calgary Stampede, which started in 1912. The tree has witnessed the drastic changes and development that Calgary’s Victoria Park area has undergone in the last century, including the construction of the Saddledome arena in 1980. Despite its longevity in its original spot, the Stampede elm sits in the location slated for the development of Calgary’s new replacement events arena. The fate of the elm during this development is currently unknown, but digital documentation took place in an effort to preserve this tree no matter what the future holds.

Digital documentation of the Stampede Elm

Digital documentation of the Stampede Elm was completed by Dr. Peter Dawson’s digital heritage research group from the Department of Anthropology and Archaeology, University of Calgary with the City of Calgary. Documentation took place on January 7, 2021 and was done with a Z+F 5010X terrestrial laser. Terrestrial laser scanning (TLS) is a form of ground-based LiDAR used to capture phenomena in 3D. Used widely in other fields, TLS is finding many applications in the field of heritage and archaeology to document built heritage structures, archaeological excavations and individual objects. The Capture2Preserv project has used this technology to document a variety of heritage sites throughout Alberta.

Z+F terrestrial laser scanner set up on tripod during documentation of the Stampede Elm. Source: Capture2Preserv project.

TLS works by firing millions of lasers out of a rotating machine; as the laser scanner itself turns in a horizontal 360o rotation on top of a tripod, a sensor rotating vertically sends out over 1,000,000 laser points per second. When these laser points hit an object, they are reflected back to the sensor. Based on the speed which light travels and the orientation of the sensor, the location of where the laser hit an object is recorded in 3D space. This process repeated over and over again generates a full 3D capture of the object in a dataset called a “point cloud”.

To capture the entirety of an object, several scanning locations are positioned around it. For the Stampede Elm, 12 scanning locations were placed in a staggered circular shape around the tree. Placing the scanner not only around the tree but at nearer and further intervals allowed for the most inclusive capture of the complicated geometry of branches.

Image showing top-down view of point cloud with scanning locations marked and numbered in red.

The resulting point cloud data is then cleaned up within a 3D editing software Autodesk ReCap. During cleaning, unwanted items such as tripods, birds and random noise picked up by the scanner can be removed. Within this program, what was captured can also be queried to within submillimeter accuracy. This means sophisticated biometrics of the tree can be taken from the data, such as volume, canopy density and trunk size.

If the tree is relocated, these data can be invaluable to arborists for planning the process of moving the tree, assessing the suitability of a new location, and comparing the health of the tree back to its pre-move status after relocation. If the tree cannot be moved, it will survive into perpetuity through the digital replica.

Sources:

City of Calgary. 2021. Calgary’s Urban Forest. Electronic document, https://www.calgary.ca/content/dam/www/csps/parks/documents/planning-and-operations/tree-management/calgarys-urban-foresty-history.pdf, accessed January 26, 2021.

Walkers, Asia. 2021. Heritage Calgary: Calmoral Circus, the City Beautiful Movement, & Calgary’s Everyday Heritage. Electronic resources, https://www.heritagecalgary.ca/heritage-calgary-blog/balmoralcircus, accessed March 30, 2021.

Breen, D. Pearce, William. Dictionary of Canadian Biography 15. University of Toronto. Electronic document, http://www.biographi.ca/en/bio/pearce_william_15E.html., accessed January 26, 2021.

The Morton Arboretum. 2021. American Elm. Electronic document, https://www.mortonarb.org/trees-plants/tree-plant-descriptions/american-elm, accessed January 26, 2021.

Babych, Stephanie. 2019. Calgary Herald, “If Only Trees If only trees could tell us stories’: Calgary’s iconic Stampede Elm could get the ax.” August 3. Electronic document, https://calgaryherald.com/news/local-news/if-only-trees-could-tell-us-stories-calgarys-iconic-stampede-elm-could-get-the-ax, accessed January 26, 2021.

Pearson, H. Global News. “How will this decades-old Calgary elm tree be impacted by the new arena?” August 2. Electronic document, https://globalnews.ca/news/5720443/calgary-old-elm-tree-stampede-grounds-new-arena/, accessed January 26, 2021.

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