Foliar respiration in an old-growth <i>Pseudotsuga-Tsuga</i> forest
Bibliographic record
Abstract
Old-growth forest ecosystems accrue carbon at small mean rates and may function as carbon sinks in some years and as carbon sources in others. Foliar respiration is a large component of stand carbon balance and could be variable enough to substantially affect sourcesink behaviors. However, foliar respiration has not been well studied in old-growth canopies. We examined seasonal, interannual, spatial, and interspecific variation of foliar respiration in an old-growth PseudotsugaTsuga stand in Washington, USA, with measurements made on three species at 3-month intervals, for 4+ years. There were strong seasonal differences, with rates being much larger in June than in December. Rates in March were significantly (p ≤ 0.0001) larger than expected for all species. For data pooled across seasons, the exponential respiration-temperature relationship indicated that a seasonal temperature increase of 10 °C caused rates to increase by 1.78 times. For respiration based on leaf area, but not on leaf mass, rates varied strongly with canopy position (p ≤ 0.0001). Temperature-corrected rates were compared among four consecutive years and declined from 1999 to 2001. Correlation with eddy covariance measurements suggests that interannual changes in foliar respiration did not cause the decline in net ecosystem productivity observed at the site through the same period, but may have instead partially offset a trend toward decreasing net ecosystem productivity caused by other factors.
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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".