Plus-tree selection of black spruce in Northwestern Ontario for Superior growing space efficiency / by Laird Van Damme. --
Notice bibliographique
Résumé
Plus-tree selection of black spruce [Picea mariana (Mill.) B.S.P.) \nbased on increment of wood volume per unit of crown (growing space efficiency) has the potential to improve yield per hectare and avoid biased \nselection of trees that have a competitive advantage in natural stands. \nIn 1981, and again in 1983, 200 and 400 trees from two 60 year-old upland \nblack spruce stands located in Northwestern Ontario were scored for \nvarious growth parameters, crown dimensions and competition indices. \nRegression analysis showed that the competition indices were poorer indicators of basal area increment (b.a.i.) than the crown parameters. \nThe crown parameter that best predicted b.a.i. was crown area (c.a.); \nr[superscript] 2 values of 0.45 and 0.57 respectively were calculated for the two black spruce stands although the slopes differed significantly. To \ntest the effectiveness of baseline selection of black spruce based on \nthe regression of b.a.i. vs. c.a., the top 10 trees were selected from \nthe second stand by this method and compared to each of the top 10 trees \nchosen by a height vs, age baseline method and a purely random method. \nOnly one tree was selected in common by each of the baseline methods. \nTrees selected by b.a.i. vs. c.a. baseline were far more variable in \ntheir size than those selected by height vs. age. Scale drawings and \nstatistical analysis of the selected trees did not reveal any easily identified \ncrop ideotype of black spruce plus-trees expressing growing \nspace efficiency. Wind-pollinated seed of the 29 selected trees was \ncollected and used to establish a short-term and a long-term progeny \ntest to investigate heritability of growing space efficiency. The \nshort-term test was conducted in a greenhouse over one growing season \nand included light intensity as a treatment, while the long-term progeny \ntest was planted in 1984 and included spacing as a treatment. \nDiscriminant analysis of Marks Lake progeny helped to identify a weak \ntrend where the tallest progeny came from short-crowned parents. Results \nof the short-term progeny test demonstrated strong family differences, \nstrong family x light interaction, but no selection method \ndifferences. Some of the family differences in the progeny could be \naccounted for by the maternal effect of seed weight, although after \nremoval of this effect by analysis of covariance, still no differences \ncould be detected between selection methods. Parent and progeny correlations for height and crown features were weak and often negative, \nwhich suggests heritability estimates for characters related to growing \nspace efficiency are likely to be as low as estimates for growth \nin general. The premature results of this study imply that if trees \nselected for superior growing space efficiency have inherent advantages \nin lower light intensities within mature stands, their juvenile \nprogeny do not express these qualities. Characters responsible for \ngrowing space efficiency are not heritable or have not yet expressed \nthemselves.
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Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,002 | 0,001 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».