Adventive-root development in mature black spruce and balsam fir in the boreal forests of Quebec, Canada
Bibliographic record
Abstract
Black spruce (Picea mariana (Mill.) BSP) and balsam fir (Abies balsamea (L.) Mill.) are the two main tree species in the boreal forests of Quebec, Canada, and both show adventive-root formation. Little is known about the dynamics of adventive-root initiation and the pattern of length growth. To gain a better understanding of root growth, the root systems of 30 mature black spruce and 30 mature balsam fir were excavated until the root diameter had decreased to 2 cm. Tree ages ranged from 100 to more than 250 years. All trees showed only adventive roots; this was confirmed by dating the rootshoot interface. The youngest lateral roots were located close to ground level, whereas the oldest ones occurred lower in the stump, suggesting a process of renewal for the latter. Reconstruction of the development of the root system revealed a specific root-growth pattern. Adventive roots grew, on average, more than 60% of their total length in the year of initiation, whereas more than 93% of lateral-root elongation was recorded in the first 10 years after adventive roots were initiated. This growth pattern was found to be similar in the two tree species in terms of lateral-root development (p = 0.68). More variability was observed for the ramified adventive roots. However, two patterns emerged. First, around 10% of total elongation was completed in the same year as that of the corresponding lateral roots. Second, several ramified adventive roots were initiated in the same calendar year but delayed by several years relative to lateral adventive root initiation. No significant differences were observed between black spruce and balsam fir (p = 0.1).
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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 | 0.002 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".