Application of process-based modelling for interpretation of stable isotope variations in tree rings
Bibliographic record
Abstract
Tree-ring width and stable isotopes (carbon, oxygen, and hydrogen) in tree-ring cellulose are widely used to reconstruct environmental conditions. The application of models capable to describe a variation of stable isotopes in annual tree rings can be a powerful tool for interpretation of environmental changes at the eco-physiological level. In this paper, we modelled carbon (delta13C), oxygen (delta18O), and hydrogen (delta2H) variations at the tree-ring level and compared results with measured data, obtained from the Mackenzie Delta River (68°30′ N, 133°48′ W) for the common period from 1901 to 2009. Using a process-based model (LPX), we were able to simulate carbon isotope values, which significantly (r = 0.29; p = 0.002) correlate with measured carbon isotope values. The model calculations for oxygen and hydrogen require further modifications and improvements, in particular the inclusion of the source of water used by the trees in the Canadian subarctic, as well as delta18O and delta2H in the water.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".