Historical drivers of street tree species selection: A comparative archival study of Canadian prairie cities
Bibliographic record
Abstract
• We examined archival documents on street trees from five Canadian cities. • Desirable species were limited by their natural and nursery availability. • Aesthetics have evolved from large tree-lined streets to ornamental species. • Species-specific ecosystem disservices resulted in the shift from poplar to elm and ash. • Conflict with utilities contributed to the use of ornamental species over elm and ash. There is a long history of planting trees along streets in cities around the world. In many cases, only a few species were used at any given time, leading to localized monocultures that increase urban forest vulnerabilities. In North America, elm and ash were historically among the most dominant tree species, yet only a nascent body of literature has examined the factors that influenced their dominance. In this study, we examine historical street tree species selection in five Canadian prairie cities, an underrepresented geography in urban environmental history literature. Using grounded theory and inductive coding, we developed a conceptual framework that explains historical biophysical and socio-political drivers of tree species dominance. The first driver is desired tree species traits. These traits, in turn, are related to the second and third drivers , species-specific ecosystem services and disservices, which influence what species are planted, avoided, or removed once they reach maturity. The fourth and fifth drivers are species availability and species-specific pests and pathogens, which were the ultimate drivers determining what species were planted on city streets. In the five study cities, Winnipeg and Regina planted American elm and green ash soon after their planting programs began because they were readily available. Calgary, Edmonton, and Lethbridge originally planted native Populus species, but later shifted to the non-native American elm and green ash due to the ecosystem disservices of Populus species at maturity, including the production of fluff and conflicts between roots and underground utilities. Today’s street tree composition reflects these legacy planting decisions.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.005 | 0.013 |
| Science and technology studies | 0.008 | 0.002 |
| Scholarly communication | 0.003 | 0.001 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".