Dynamics of an old-growth, fire-initiated, subalpine forest in southern interior British Columbia: tree-ring reconstruction of 2 year cycle spruce budworm outbreaks
Bibliographic record
Abstract
Tree-ring width chronologies of three species from a 330-year-old subalpine forest were used to reconstruct outbreaks of 2 year cycle spruce budworm (Choristoneura biennis Freeman). The growth of host species, Engelmann spruce (Picea engelmannii Parry ex Engelm.) and subalpine fir (Abies lasiocarpa (Hook.) Nutt.), was compared with that of the nonhost, lodgepole pine (Pinus contorta Dougl. ex Loud.) with and without the removal of the effects of climate on growth. Seven periods, 19891991, 19431957, 19111927, 18691875, 18391861, 18231829, 17851801, were identified in which the growth of both host species was reduced relative to the non-host; this includes the single known outbreak from 1944 to 1956. Spectral analysis indicated a periodicity for growth reduction of the host relative to non-host species of ca. 45 years for both spruce and fir. For three periods, the known outbreak in the 19401950s, and two inferred outbreaks in the 19101920s and 18401850s, we calculated the four measures of radial growth first proposed by Brubaker and Greene (L.B. Brubaker and S.K. Greene. 1979. Can. J. For. Res. 9: 95105): the maximum rate of growth loss, 1-year and 5-year losses, and the rate and time to recovery. Growth losses were greater for fir than for spruce during all three periods. During the 19401950s, growth losses were severe, but losses were less in the 19101920s. The impact of C. biennis has varied among outbreak periods but, overall, has made a pronounced contribution to present stand conditions. Our work suggests that budworms have been a frequent agent of disturbance with major effects on forest dynamics in southern British Columbia, especially in sprucefir forests when long periods occur between fires.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 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".