The effects of spacing and genetic factors on growth and tree form quality traits of plantation-grown jack pine
Bibliographic record
Abstract
Overall tree form ofjack pine (Pinus banksiana Lamb.) growing in natural stands \nvaries from straight slender trees with compact crowns to broad, limby and even multi-stemed \ntrees. Jack pine grown in plantations at conventional spacings of 2 m develops \nform traits undesirable for forestry utilization. The goal of this study was to investigate \nthe effects and interaction of spacing and genetic factors on plantation-grown jack pine to \ndetermine the potential benefit of a selection program based on form traits. Ten wind-pollinated \nfamilies were collected from each of six natural fire-origin stands from east \nand west of Lake Nipigon in northwestern Ontario that had been subjectively rated as \ngood, average and poor in form. These sixty families making up six form-quality groups, \ntogether with an additional twenty plus tree families making up two more form-quality \ngroups, were established at two planting sites with contrasting soil texture and fertility at \nspacings of 1, 2 and 3 m. Eight tree form quality traits?branch length, branch diameter, \nbranch angle, branch number, relative branch diameter, relative crown width, number of \ncrooks, and taper were measured and analyzed together with two growth traits?height \nand diameter at breast height (DBH) at age eight. General linear models were used to \nevaluate the effects of site, spacing, form-quality group, family and the relevant \ninteractions on all traits except number of crooks which was not normally distributed. All \njack pine growth and form traits except branch number were greatly affected by spacing. \nMost of the change in form traits occurred when spacing increased from 1 to 2 m with \nlesser change from 2 to 3 m. This effect was more pronounced at the more fertile test site. \nForm-quality groups were significantly different for only two of the form traits?branch \nlength and branch angle with this effect again being more evident at the fertile test site. \nHowever, the family effect was significant for all seven tested form traits as well as the \ntwo growth traits suggesting that any of these traits would readily respond to family \nselection. A definite provenance effect was demonstrated for growth traits and stem \ntaper; the western sources grew faster with more favourable taper. None of the form quality \ngroup X spacing nor the family x spacing interactions were significant. \nHeritabilities and genetic correlations were determined for all traits separately for each \nspacing at each test site. Traits height, branch angle and taper had the highest \nheritabilities, with individual heritabilities of greater than 0.15, and the traits branch \ndiameter, relative branch diameter and relative crown width had values less than 0.05. \nThe two growth traits together with growth-related form traits tended to be strongly \npositively correlated with the exception of height and relative crown width. However, \nbranch angle and branch number showed no strong correlations with any other tree form \nand growth traits. Both heritabilities and genetic correlations were more meaningful for \nthe more fertile test site due to larger components of family variance.
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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 | 0.000 | 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".