A simple technique to measure stem respiration using a horizontally oriented soil chamber
Bibliographic record
Abstract
This paper introduces a simple technique, the horizontally oriented soil chamber (HOSC), to measure stem and branch respiration easily and accurately. We extend the function of the LI-6400-09 soil CO2 flux chamber by attaching a custom-built polyvinyl chloride (PVC) collar to the stem surface. For small trees and branches we use pipe bushings to connect the chamber to stem surface. Using this technique we measured stem respiration in a young ponderosa pine (Pinus ponderosa Dougl. ex Laws.) plantation in the Sierra Nevada Mountains near Georgetown, Calif., from June to December 1998. The diurnal and seasonal variations in respiration rate correlate well with the corresponding stem temperature variation. The Q10 values varied from 1.9 to 2.8, which are within the range of Q10 values (1.3-3.3) reported in previous studies. The range of our stem respiration results (3.5-7.2 µmol·m-2·s-1) compares favorably with previous studies on young ponderosa pine trees. This technique provides an alternative to measure stem respiration, which employs widely used, commercially available, portable respiration measurement equipment and requires almost no additional equipment, especially for current owners of LI-6400 systems. Thus, the HOSC technique is appropriate for examining spatial variation of stem respiration.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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".