Spatial patterns and competition of tree species in a Douglas‐fir chronosequence on Vancouver Island
Bibliographic record
Abstract
While the successional dynamics and large‐scale structure of Douglas‐fir forest in the Pacific Northwest region is well studied, the fine‐scale spatial characteristics at the stand level are still poorly understood. Here we investigated the fine‐scale spatial structure of forest on Vancouver Island, in order to understand how the three dominant species, Douglas‐fir, western hemlock, and western redcedar, coexist and partition space along a chronosequence comprised of immature, mature, and old‐growth stands. We quantified the changes in spatial distribution and association of the species along the chronosequence using the scale‐dependent point pattern analyses pair‐correlation function g(r) and Ripley's L‐function. Evidence on intra‐ and inter‐specific competition was also inferred from correlations between nearest‐neighbor distances and tree size. Our results show that 1) the aggregation of Douglas‐fir in old‐growth was primarily caused by variation in local site characteristics, 2) only surviving hemlock were more regular than their pre‐mortality patterns, a result consistent with strong intra‐specific competition, 3) inter‐specific competition declined rapidly with stand age due to spatial resource partitioning, and (4) tree death was spatially randomly distributed among larger overstory trees. The study highlights the importance of spatial heterogeneity for the long‐term coexistence of shade‐intolerant pioneer Douglas‐fir and shade‐tolerant western hemlock and western redcedar.
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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 | 0.001 | 0.001 |
| 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".