Dendrochronological reconstruction of spruce budworm (<i>Choristoneura fumiferana</i>) outbreaks in southern Quebec for the last 400 years<sup>1</sup>This article is one of a selection of papers from the 7th International Conference on Disturbance Dynamics in Boreal Forests.
Bibliographic record
Abstract
It is argued that spruce budworm ( Choristoneura fumiferana (Clemens)) (SBW) outbreaks have tended to be more frequent, severe, and spatially synchronized since the beginning of the 20th century. However, few studies have assessed the long-term (>200 years) variations in SBW outbreak dynamics. We reconstructed the SBW outbreak history at the northern limit of the temperate forest in southern Quebec using dendrochronological material from old buildings and five old-growth stands. Our regional tree-ring chronology (1551–1995) represents one of the longest and most replicated insect outbreak reconstructions in North America. Nine potential outbreaks were identified (1976–1991, 1946–1959, 1915–1929, 1872–1903, 1807–1817, 1754–1765, 1706–1717, 1664–1670, and 1630–1638) with three additional uncertain outbreaks (1647–1661, 1606–1619, and 1564–1578). Results suggested that southern Quebec has experienced frequent and synchronized outbreaks throughout the last 400 years. Although outbreak frequency was higher during the 20th century (approximately 30 years) as compared with the 1660–1850 period (approximately 50 years), similar or even higher outbreak frequency might have occurred prior to 1660 (approximately 28 years). We did not find any evidence that the recent outbreak dynamics in southern Quebec is outside its historical range of the last 400 years. Previous studies based on living trees may have underestimated outbreak frequency and synchrony prior to 1900.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".