Preventing crown collisions increases the crown cover and leaf area of maturing lodgepole pine
Bibliographic record
Abstract
Summary Crown collisions induced by tree sway are hypothesized to reduce crown closure and leaf area in maturing cold temperate forests. These declines are thought to lead to the decline in productivity when a stand ages. We tethered groups of lodgepole pine ( Pinus contorta Dougl. Ex Loud. Var. latifolia Engelm.) trees in a web pattern at 10 m height, in four 15‐m tall stands in western Alberta, Canada, to determine whether preventing crown collisions would increase crown cover and leaf area. The stands all had less than 65% crown closure at the beginning of study. Photographs of the canopy were taken in each control and webbed plot in 1998 and at the same point in 2004. Six years after webbing, crown cover had increased by 14.4%, compared to a 2.1% increase for the control plots. Webbing also resulted in significant increases in mean branch length, leaf area per branch and foliage density of individual branches from top and middle sections of the crown. Polishing of branches, caused by chronic contact with adjacent trees, was three times as common on control trees compared to webbed trees. The mean leaf area per tree was larger for the webbed trees. Crowns of webbed trees were more symmetrical than those of control trees. Trees from webbed plots, however, had a decline in leaf area density. The branches of control trees were typically curved upward with twigs pointed inward, making the crowns more compact compared to the outwardly expanding crowns of trees from the webbed plots. The fact that crowns expanded laterally after webbing, despite little change in light regime, provides strong evidence against the hypothesis that loss of crown closure in maturing stands is caused by a lack of light. The study indicates that the decline in crown closure and leaf area in maturing and tall stands is at least partly related to wind‐induced sway of trees abrading the edges of crowns.
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 | 0.000 | 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 | 0.000 | 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".