Impact studies on Nordic forests: effects of elevated CO<sub>2</sub> and fertilization on gas exchange
Bibliographic record
Abstract
The effects of rising atmospheric carbon dioxide concentration, [CO2], and fertilization on gas exchange of four field-grown tree species were examined using the branch bag technique (Picea abies (L.) Karst., Pinus sylvestris L., Fagus sylvatica L.) or whole tree chambers (Populus trichocarpa Torr. & Gray). Results are presented on changes in light-saturated rates of net photosynthesis (Asat), carboxylation efficiency (α), stomatal conductance (gs), and stomatal limitation of photosynthesis (Ls) after 24 years of CO2 exposure. Fertilization alone did not significantly change Asat, α, gs, or Ls for any of the species, but α and Asat were linearly related to foliage nitrogen content when compared across all treatments. No significant CO2 effects were detected for α, gs, or Asat when compared at the same intercellular [CO2], i.e., no downregulation of Asat was apparent. "Long-term" CO2 enrichment increased Asat significantly by 49, 53, 86, and 114% in Populus trichocarpa, Picea abies, F. sylvatica, and Pinus sylvestris, respectively. In all the species the relative CO2 effect on Asat increased linearly with temperature. Thus, application of a simple linear relationship could improve predictions of future tree growth responses to increasing CO2 and temperature in cool climates.
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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".