Impact of precommercial thinning in balsam fir stands on soil nitrogen dynamics, microbial biomass, decomposition, and foliar nutrition
Bibliographic record
Abstract
Precommercial thinning is being tested in Quebec as a preventive silvicultural treatment to reduce vulnerability of young balsam fir (Abies balsamea (L.) Mill.) stands to spruce budworm (Choristoneura fumiferana (Clem.)) damage and to shorten rotations. As part of a larger study of ecosystem response to thinning, we have examined the impact of this treatment on soil nitrogen dynamics, microbial biomass, cellulose decomposition, and foliar nutrition across a range of drainage conditions (good, imperfect, and poor). In the first year after thinning, initial early season ammonium (NH 4 + -N) pools in the mineral horizon were significantly higher in the thinned plots (P = 0.019), while net nitrogen mineralization (NH 4 + -N plus NO 3 - -N) decreased in these same plots (P = 0.052). The thinning treatment significantly increased microbial biomass nitrogen (N mic ) in the organic horizon (P = 0.051). Simple regression analysis indicated the importance of soil temperature in controlling N mic . Decomposition of cellulose substrate in the organic horizon was significantly increased by thinning, and mass loss was related to soil temperature. Increased decomposition and nutrient availability after thinning were reflected in improved N, P, and K nutrition in current, 1- and 2-year-old balsam fir needles. The temporal extent of this improved fertility will be verified by longer term monitoring.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 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 teacher head, 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".