Effects of Biomass Removal Levels on Soil Carbon and Nutrient Reserves in Conifer‐Dominated, Coarse‐Textured Sites in Northern Ontario: 20‐Year Results
Bibliographic record
Abstract
Core Ideas Biomass removal trials targeted soils sensitive to nutrient removal (shallow to bedrock and infertile sands). 14 long‐term sites (42 plots per treatment) were used to evaluate C and nutrient reserves 20 years post‐harvest. After 20 years, soil C, N, and K reserves did not differ between pre‐harvest levels and SO and FT. Soil reserves of FTB treatments remained significantly lower than the pre‐harvest levels. Jack pine and black spruce declined in height on FTB on sandy sites; there were no differences between SO and FT. Here we report on 20‐yr soil (forest floor plus the upper 20 cm of mineral soil) carbon and nutrient reserves from 14 biomass removal trials established on coarse‐textured, nutrient poor sites. Harvest treatments included stem only (SO, delimbed at the stump), full‐tree (FT, entire trees with boles and branches removed), and full‐tree plus forest floor blading (FTB, full‐tree harvest followed by removal of the forest floor and approximately the upper 5 cm of mineral soil). After 20 yr, there were no significant differences in soil C, N, and K reserves between pre‐harvest levels and the SO and FT treatments. Only the soil reserves of the FTB treatment remained significantly lower than the pre‐harvest levels. Extractable soil Ca and Mg reserves increased in Year 5 in all treatments, followed by slow declines, but all treatments remained comparable to or exceeded pre‐harvest levels at Year 20. For P, harvesting (SO and FT) resulted in significant declines that remain after 20 yr. Both jack pine and black spruce showed reduced top height growth on FTB, but only on some of the sandy sites. There were no differences in top height for either species between SO and FT across all 14 study sites. Current results suggest there is no need for restrictions on full‐tree harvesting for traditional wood products on these nutrient poor sites. However, from a cautionary perspective, it seems prudent at this time to restrict more intensive bioenergy harvests to deep, finer‐textured sites that have larger soil C and nutrient reserves.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| 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".