Regeneration of Picea engelmannii and Abies lasiocarpa in high-elevation forests of south-central British Columbia depends on nurse logs
Bibliographic record
Abstract
We studied the regeneration niche of Picea engelmannii and Abies lasiocarpa in wet sub-zones of the Engelmann spruce-subalpine fir (ESSF) zone of southern British Columbia. We characterized the niche on transects from clearcuts into adjacent old-growth stands, in terms of aspect, elevation, micro-relief, light, seedbed, canopy cover, and competing vegetation. Fourteen transects were sampled at four watersheds. The sampling design ensured similar representation of small (130 cm), medium (31100 cm) and tall (101300 cm) saplings, and of both species. In total, 465 Picea and 623 Abies saplings were sampled. For every third sapling, an adjacent microsite with no sapling was selected using a random procedure and correspondingly characterized, enabling a pairwise comparison of microsites with and without saplings. Recruitment of both species was related to rotten wood seedbeds, i.e., mainly logs, but also stumps and root plates. This effect was stronger for Picea saplings, and it decreased with increasing sapling size, suggesting lower survival on rotten wood seedbeds. A higher occurrence of tall Abies saplings, in comparison to small ones, under the cover of canopy trees suggests higher survival under canopy than in gaps. Levels of direct light did not generally differ either between microsites with and without regeneration, or between Picea and Abies saplings. The microsite effects on sapling occurrence were quite consistent across gentle south- and north-facing slopes, upper and lower ESSF forests, sites, and along clearcut old-growth gradients. The results suggest a strong dependence of Picea and Abies establishment on logs in ESSF forests. Key words: seedling establishment, microsite, seedbed, nurse logs, direct light, advance regeneration, ecological niche
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| 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 teacher head, 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".