Tree ring width and isotope ratios show that high temperatures exceed pollution effects on urban trees: evidence in Pinus pinea in Firenze and Pisa, Central Italy
Bibliographic record
Abstract
Abstract Urban areas typically experience higher temperatures and reduced precipitation compared to periurban environments, conditions that may strongly influence tree performance. To assess these effects, we studied Pinus pinea in Firenze and Pisa, integrating dendroecological and stable isotope analyses. Ring-width index data did not reveal significant differences in radial growth between urban and periurban trees, suggesting that growth responses alone may underestimate urban stress. In contrast, isotopic analyses provided clearer evidence: δ 13 C and δ 18 O values indicated marked water stress in urban trees, particularly in Firenze, while δ 15 N and F 14 C suggested minimal incorporation of traffic-derived nitrogen or fossil CO 2 , likely due to the protective role of urban parks. These findings highlight an apparent discrepancy, where tree growth suggests resilience, while physiological signals reveal stress linked to urban microclimates. This emphasizes the value of combining multiple indicators to capture tree responses in complex environments. Overall, our results suggest that urban climate exerts a stronger influence on P. pinea than localized traffic emissions, with implications for tree vitality and ecosystem services. Species selection for urban forestry should therefore account for microclimatic constraints to ensure long-term tree performance under ongoing urbanization and climate change.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".