Stand density in the last millennium at the upper tree-line ecotone in the Polar Ural Mountains
Bibliographic record
Abstract
Significant spatiotemporal changes in the establishment, mortality, and abundance of trees have taken place in the upper tree-line ecotone in the Polar Ural Mountains over the last millennium. Until now, these forests have developed mainly under the influence of natural factors. A large number of well-preserved tree remains can be found up to 6080 m above the current tree line, some dating to as early as a maximum of 1300 years ago. The research reported here extends the work begun by S.G. Shiyatov, who examined evidence of tree growth dynamics along a transect on the eastern slope of the Polar Ural Mountains in the 1960s. For this study, 769 discs from dead trees and 378 increment cores from living trees were collected along an altitudinal transect 860 m long and 80 m wide. The positions of all living trees, fallen dead trees, and wood remains were mapped. Dimensions of each living tree, including saplings and understory plants, were measured: basal diameter, diameter at breast height, crown diameter, and height of stems. Calendar years of tree germination and death were estimated using dendrochronological techniques. The earliest distinct maximum in stand density occurred in the 11th to 13th centuries, coincident with Medieval climate warming. Climate warming in the 18th century appears to have resulted in a second stand-density maximum. The recent temperature increase observed in the 20th century is reflected in the high number of young trees observed.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 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) | 0.000 | 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".