Patterns of late-season photosynthate movement in sugar maple saplings
Bibliographic record
Abstract
A more detailed understanding of seasonal dynamics of carbon allocation between roots and shoots of temperate zone trees is needed. We labeled sapling stands of sugar maple ( Acer saccharum Marsh) with 13CO2 in four 3 m diameter chambers during a 3 week interval in September 2006 and traced the movement of this 13C pulse through trees and soil during autumn and spring. High enrichment of 13C in foliage was achieved (δ13C = 387‰ ± 16‰). Late-season photosynthate was strongly mobilized during leaf senescence and stored in twigs, wood, and roots. Very high 13C enrichment of soil CO2 emissions at this time (δ13C = 766‰ ± 82‰) indicated the role of late-season photosynthesis in supplying root metabolism after the growing season. Rhizosphere soil was weakly enriched in 13C during fall, and increased significantly over the winter. Earthworms were highly enriched in fall, indicating that they consumed roots. In spring, 13C was strongly mobilized to growing shoots but not to growing fine roots; apparently, fine root growth in spring was not supplied by late-season stored photosynthate. These results provide insights into the seasonal dynamics of temperate tree carbon allocation with implications for disruption of these dynamics by global warming.
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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) | 0.001 | 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".