An 1800-year record of the spatial and temporal distribution of fire from the west coast of Vancouver Island, Canada
Bibliographic record
Abstract
Charcoal records from lake sediments may show changes in fire frequency over thousands of years, but such records are ambiguous with regard to the actual locations of fires. Using a comparison of fire dates from an 1800-year lake sediment record from the west coast of Vancouver Island (British Columbia, Canada) and dates of last fire from 38 sites in the same watershed using tree-ring and soil-charcoal 14 C dates, we estimated the source area that contributes to charcoal peaks and determined the degree to which fires were biased to certain locations. Twenty-three charcoal peaks, likely corresponding with individual fire events, were objectively identified from the sediment record. Comparison of fire dates from charcoal peaks in the sediment record with fire dates from points near the lake suggests that the charcoal source area is within 500 m of the lake edge. Fire occurrence within this charcoal source area increased sharply at AD 1100 from ca. 50 to ca. 300 years between charcoal peaks, coeval with the first "Little Ice Age" cooling. Soil-charcoal radiocarbon dates revealed that 37% of the charcoal source area had not burned over the last 1800 years and that the 23 fires identified in the sediment record were restricted to south-facing slopes near the lake. This spatial pattern may result only if fire is >25 times more likely to occur on susceptible sites (south-facing slopes) than on less susceptible sites. This strong bias in fire location ensured the millennial-scale persistence of large areas of late-successional forest through past climatic periods.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.003 |
| 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) | 0.001 | 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".