Regional variation in the proportion of red heartwood in sugar maple and yellow birch
Bibliographic record
Abstract
Stems of sugar maple (Acer saccharum Marsh.) and yellow birch (Betula alleghaniensis Britt.) trees often contain a column of discoloured wood known as red heartwood, which reduces lumber value. To quantify the regional-scale variation in red heartwood, 192 trees of each species were sampled in 12 locations across the temperate forest zone of southern Québec, Canada. Large regional variation in the radial proportion of red heartwood (RHP) at breast height (1.3 m) was observed in both species. Statistical modeling showed that such variation was mainly attributable to factors related to tree development. Cambial age had a strong positive effect on RHP in both species, suggesting that the occurrence of red heartwood ultimately might be unavoidable. There was also a positive effect of ring area increment at the limit of the discoloured zone. In the case of sugar maple, there was an added effect of the trend in ring area increments observed in the same zone, with a negative trend being generally indicative of a larger RHP. Further variability in this species was also associated with the annual minimum temperature of the sampling locations. The models developed for each species explained around 60% of the variance in RHP and could be used to improve forest management and wood procurement decisions.
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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 | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 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".