A study of self-thinning using coupled allometric equations: implications for coastal Douglas-fir stand dynamics
Bibliographic record
Abstract
The 3/2 self-thinning rule was proposed with the hypothesis that in closed canopy stands, plant mass is proportional to the cube of a linear size dimension, and that density is proportional to the square of this dimension, thus defining the isometric model. To account for the morphological differences among species, the allometric model was proposed as a refinement of the isometric model, therefore linking the self-thinning exponent's dependence to species-specific allometric parameters. In this study, it is proposed that each stand has its own self-thinning trajectory boundary, determined by its own unique stand allometry. An S-system is used to facilitate coupled allometric relationships under the influence of self-thinning. Upon calibrating this model to Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) permanent sample plots, located throughout western Washington, western Oregon, and southwest British Columbia, the implications of coupled allometric equations are discussed and compared with the algebraic, isometric, and allometric models. The results support the use of simultaneous, coupled rate equations versus uncoupled static ones.
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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 | 0.007 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 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".