Boundary-Line Approach to Determine Standards of Nutrition for Mature Trees From Spatial Variation of Growth and Foliar Nutrient Concentrations in Natural Environments
Bibliographic record
Abstract
Optimum nutritional standards for most tree species of eastern Canada are unknown. This can be attributed to the fact that controlled conditions typically required to develop such standards are impractical and prohibitive to obtain with mature trees. In this study, a boundary-line approach was developed for determining standards of optimum nutrition for forest trees based on natural variation in tree growth and nutritional status. The study site was located in the unmanaged forest of the Station de Biologie de l’Université de Montréal, 90 km north of Montreal in the Lower Laurentians in Quebec. As many as 87 dominant to codominant sugar maples were sampled (foliage, increment cores) and measured (live-crown ratio, dendrometer bands) over the 1995–2001 period. Leaves were analyzed for nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and manganese (Mn), and radial growth was converted to basal-area growth for use with the boundary-line approach to determine standards of nutrition. An algorithm was developed to select boundary points to be used in quadratic models describing the relationships between leaf-nutrient concentration and basal-area growth. Eight, 10, and 20 intervals (points) and an index based on the live-crown ratio of the trees to correct for forest density were tested. The application of the boundary line on raw data without correction for outliers or live-crown ratio generally produced models that were significant. Correction of outliers and the use of 10 intervals generally improved the models. Critical and optimum leaf N, P, K, Ca, Mg, and Mn concentrations derived from the boundary-line approach were generally similar to published values. These results suggest that the approach is particularly well suited for the determination of critical and optimum nutrient concentrations and is less so for the determination of toxic concentrations.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.004 | 0.015 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".