Évolution de la structure diamétrale et production ligneuse des pessières noires issues de coupe et de feu
Bibliographic record
Abstract
The widespread use of careful logging in the province of Quebec raises many questions about the effects of this practice on the structure and productivity of boreal black spruce (Picea mariana (Mill.) BSP) stands compared with fire-origin stands that are currently being harvested. The objective of this study is to describe and compare the evolution pattern of the diameter structure of stands originating from fire or logging dating back to the first half of the 20th century. The dendrochronological approach allowed the reconstitution of the dynamics of 40- to 96-year-old stands. Second-growth stands differ from fire-origin stands by their highly hierarchized initial structure. After the recruitment period, the degree of hierarchy of the structure of second-growth and fire-origin stands is comparable. After logging, the diameter structure of black spruce stands keeps a higher skewness index than that of stands originating from fire. For both stand types the skewness decreases or remains constant with time, which invalidates the model proposed by Mohler et al. (C.L. Mohler, P.L. Marks, and D.G. Sprugel. 1978. J. Ecol. 66: 599614). This observation questions the existence of a strong asymmetric competition among trees in black spruce stands. Results indicate that the yield of black spruce stands originating from clearcuts from the early 20th century is higher than or equal to fire-origin stands mainly because (i) basal area was maintained to levels higher than or equal to fire-origin stands and (ii) most advanced growth was taller that 1 m at the time of logging.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".