Land‐use conversion effects on CO <sub>2</sub> emissions: from agricultural to hybrid poplar plantation
Bibliographic record
Abstract
Abstract Land‐use changes such as deforestation have been considered one of the main contributors to increased greenhouse gas emissions, while verifiable C sequestration through afforestation projects is eligible to receive C credits under the Kyoto Protocol. We studied the short‐term effects on CO 2 emissions of converting agricultural land‐use (planted to barley) to a hybrid poplar ( Populus deltoids × Populus × petrowskyana var. Walker) plantation in the Parkland region in northern Alberta, where large areas are being planted to hybrid poplars. CO 2 emissions were measured using a static gas chamber method. No differences were found in soil temperature, volumetric moisture content, or soil respiration rates between the barley and Walker plots. The mean soil respiration rate in 2005 was 1.83 ± 0.19 (mean ± 1 SE) and 1.89 ± 0.13 μmol CO 2 m −2 s −1 in the barley and Walker plots, respectively. However, biomass production was higher in the barley plots, indicating that the agricultural land‐use system had a greater ability to fix atmospheric CO 2 . The C balance in the land‐use systems were estimated to be a small net gain (before considering straw and grain removal through harvesting) of 0.03 ± 0.187 Mg C ha −1 year −1 in the barley plots and a net loss of 3.35 ± 0.080 Mg C ha −1 year −1 from the Walker poplar plots. Over the long‐term, we expect the hybrid poplar plantation to become a net C sink as the trees grow bigger and net primary productivity increases.
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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) | 0.002 | 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".