Reaching new heights: Chemical signatures of lodgepole pine trees change with elevation, but not with latitude
Bibliographic record
Abstract
The lodgepole pine (Pinus contorta var. latifolia) is Alberta’s provincial tree and critical to the forest industry. This pine species is the historical host for mountain pine beetle (Dendroctonus ponderosae Hopkins, Coleoptera: Curculionidae, Scolytinae). In western Canada, mountain pine beetle is expanding its range facilitated, in part, by climate-change, and has invaded areas that were historically climatically unsuitable to its survival. As a result, novel lodgepole pine stands in Alberta are being invaded. Thus, it is timely to predict if the vulnerability of lodgepole pine trees varies across the province’s elevational and latitudinal gradients. Elevation or latitude can be used as space-for-time gradients in climate change studies. Host susceptibility to bark beetles is usually assessed via tree defenses. The primary defenses of lodgepole pine against bark beetles are the constitutive concentration of oleoresin terpenoids. Production of these defense chemicals relies in part on tree reserves, and non-structural carbohydrates (sum of total sugars and starch). I investigated whether the concentration of monoterpenes, diterpene resin acids, and non-structural carbohydrates of lodgepole pine trees change as a function of elevation or latitude. I characterized the chemical profile of trees along an elevational gradient of 1,251m, and a latitudinal gradient of 736 km. I also determined age, growth rates, basal area index values, stand density, and basal area. I found that concentrations of terpenes increased with elevation while soluble sugars decreased. Latitude had no effect. Overall, this project shows that pine trees occurring at higher elevations have a greater concentration of constitutive defense compounds, and a lower concentration of glucose and sucrose. These findings call for future research to determine inducibility of the same defense compounds at high elevations, and stress the importance of considering plant defenses against range expanding insect herbivores in forest pest management.
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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 | 0.001 | 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".