Serpentine Galleries

Emerald Ash Borer, the iridescent green beetle feeding on the ash trees of Ontario, Quebec, and the eastern United States, carves winding paths beneath the bark of its host tree. These wandering lines (“serpentine galleries,” plant biologists call them11Kenneth R. Marchant, “City of Mississauga Emerald Ash Borer Management Plan,” City of Mississauga, 2012, http://www7.mississauga.ca/documents/parks/forestry/2014/Management_Plan_Final_22Jan12.pdf.) trace the fatal effects of the beetle, whose feeding inhibits the movement of nutrients throughout the tree.

The patterns cut by this invasive species have been used to aesthetic effect in woodworking projects made from reclaimed ash wood. Beginning in 2014, Mississauga’s Partners in Project Green and Sawmill Sid spearheaded a region-wide reuse project for dead ash that has yielded a wide variety of wood products, and similar efforts are underway across the GTA. Such upcycling aims to create positive outcomes from the infestation, and in some cases these projects symbolically retain the traces of the beetles’ movements.

Whereas reclamation projects take advantage of fine woodworking and carpentry, it is believed that a much humbler wood product originally transported the beetle to this continent. A wooden crate carrying Japanese car parts allegedly caused the infestation in the Windsor–Detroit area in the early 1990s.22Oliver Rackham, The Ash Tree (Dorset: Little Toller Books, 2014), 132–133. A passenger on the circuits of global trade, the Emerald Ash Borer owes its fortune to the mobility of commodities.

Mitigating the problem demands the opposite: a regional quarantine to prevent the further spread of the beetle. These regulations are most evident at national and provincial parks, where firewood is under strict scrutiny. Such constraint—where resources are compelled to remain near their place of origin—is rare in a world where plants and soils are transnational travellers among nurseries and plantations. Anthropologist Anna Tsing identifies the latter as a root cause of the devastating environmental effects of modernity. Plantations, she writes, “are machines of replication, ecologies devoted to the production of the same.”33Anna Tsing, “Earth Stalked by Man,” The Cambridge Journal of Anthropology 34, no. 1 (Spring 2016), 4. This phenomenon amplifies the destructive effect of invasive species, which can surge through monocultural plantations unimpeded by natural barriers to their advance.

Plantations and invasive species challenge the conventional understanding of ecosystems as cyclical and harmonic entities. As social scientist Nigel Clark argues, invasive species reveal the turbulence inherent to ecosystems: transplanted life provokes “disaster,” which “stimulates the pressures of selection, at once testing life’s tolerance and galvanizing its creativity.”44Nigel Clark, “The Demon-Seed: Bioinvasion as the Unsettling of Environmental Cosmopolitanism,” Theory, Culture & Society 19, no. 1–2 (Spring 2002), 113. Whereas environmental education often compartmentalizes ecosystems into distinct units (wetlands, forests, plains), movement and migration potentially dissolve and recompose ecosystems. As Clark writes: “If it is in the ‘nature’ of life to stick to its home turf, why exactly are there species from all across the taxonomic spectrum that seem so eager for relocation, and so well-disposed to it?”55Ibid., 112.

A fuller picture of the Emerald Ash Borer infestation requires an understanding of plantations and invasive species in the context of global commerce. The beetle, after all, is relatively benign in its places of origin: Asian ash trees evolved to resist its fatal effects. It is only in a new ecosystem—one intensively mediated by human activity—that the beetle’s devastation is made possible. In Mississauga, these factors converge: ash trees make up an estimated ten percent of the tree canopy, and all are at risk if left unattended.66“Emerald Ash Borer,” City of Mississauga, http://www.mississauga.ca/portal/residents/parks-emerald-ash-borer. As early growers in the forest life cycle, ash trees thrive in disturbed ecosystems, and they were historically planted as street trees during the city’s urbanization process.77Marchant, “City of Mississauga Emerald Ash Borer Management Plan,” 18.

Rattray Marsh Conservation Area, on the shore of Lake Ontario, forcefully testifies to the devastation wrought by the Emerald Ash Borer. The marsh was used as farmland from the nineteenth century through to the 1950s, and afterwards ash spread widely on the disused fields—thus the end of plantation agriculture laid the groundwork for another fragile ecosystem.88Ruth Hussey and Judith M. Goulin, Rattray Marsh Then and Now (Mississauga: Rattray Marsh Protection Association, 1990), 80–81. The 95-acre conservation area contained over 2,000 ash trees before hundreds of infested ones were recently removed.99Kevin DeMille, “Emerald Ash Borer Impact to Rattray Marsh Conservation Area,” presentation for Credit Valley Conservation, 2014, https://cvc.ca/wp-content/uploads/2014/05/Rattray-EAB-Meeting3.pdf. Mitigation and conservation practices at Rattray have necessitated dynamic, laborious, and techno-scientific processes. Tree pruning, removal, and wood-chipping, alongside ongoing treatments with biological insecticides for living trees, attest to the fact that conservation is largely a process of human intervention in human-caused situations.

In the challenges it poses to conservation practices and large-scale agriculture, the Emerald Ash Borer infestation raises important questions for the era of climate change. Itself a passenger in human affairs, this invader requires us to reckon with our beliefs about the natural environment. Its serpentine galleries map out paths of commerce, globalization, agriculture, and urban development. Tracing these lines, we are forced to ask: What constitutes a stable ecosystem? How can our ideas of conservation and preservation account for invasion, migration, and destruction? And which forms of life are being preserved at the expense of others?