Reduction in branch sapwood hydraulic permeability as a factor limiting survival of lower branches of lodgepole pine
Bibliographic record
Abstract
Branch sapwood hydraulic permeability, tracheid size, and earlywood to latewood ratio of annual rings were examined in lower and upper branches of closed-canopy and open-grown lodgepole pine (Pinus contorta Dougl. ex Loud.) trees. Hydraulic permeability, expressed on either a leaf area or sapwood area basis, was lower in lower branches (0.16 × 10-5 and 5.82 × 10-5 m2, respectively) than upper branches (0.26 × 10-5 and 10.47 × 10-5 m2, respectively) and was related to narrower tracheids in the sapwood of lower branches. Earlywood/latewood ratio declined in the lower branches of shaded trees. The hydraulic conductivity of upper and lower branches in closed canopy trees was reduced by drilling small holes radially through the stem. Stomatal conductance was lower, and after a growing season there was greater foliage mortality in drilled lower crown branches than in similarly treated upper branches, suggesting that the hydraulic conductivity of lower branches was closer to the lower limit required to maintain foliage than in upper branches. These data suggest that high foliage mortality and eventual death of lower branches does not occur solely because of low light but also from reduced stomatal conductance and photosynthesis resulting from shade-initiated reductions in earlywood, tracheid diameter, and branch hydraulic conductivity.
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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 | 0.000 |
| 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 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".