Effect of competition on the growth and crown form of lodgepole pine
Notice bibliographique
Résumé
Tree growth and crown form of 131 open-grown and 63 forest-grown lodgepole pine were investigated. Areas sampled included representative sites in the Interior, Lower Mainland and Vancouver Island in British Columbia. Both graphical and multiple regression analyses were used. The best, but still inadequate, estimator of either radial or basal area growth for the last five years was the growth for the period six to ten years ago. Standard errors of estimate ranged from 21.4 percent for basal-area growth of individual open-grown trees to 43.5 percent for basal-area growth of individual forest-grown trees. More than 90 percent of the total variation in the crown width of open-grown lodgepole pine was accounted for by d.b.h. alone. For forest-grown trees only 56.8 percent was accounted for by d.b.h. This percentage may be increased to 81.1 percent by the addition of height-crown width (H/CW), and to 68.4 percent by the addition of crown width/diameter (CW/D). Average value for CW/D was 0.99 for the forest-grown, and 2.13 for 90 open-grown trees ten years of age or older. Both H/CW and CW/D are significantly related to site index and age. However, when d.b.h. is taken into account, only six percent of the variation in CW/D is affected by site index. Almost 50 percent of the height to the lowest dead branch, and over 90 percent of the height to the lowest live branch could be accounted for by tree age, d.b.h. and height. One of four "competition factors", all related to distance to, and size of, competing trees, accounted for an additional 13.7 percent of the variation in height to dead branches. However, basal area, H/CW, and CW/D were of little importance after the effects of age, d.b.h. and height were accounted for. The maximum growth rate for open-grown trees was determined graphically for ages from 30 to 50 years by site index classes. Comparison with normally grown trees showed that at least twice the normal yield-table-estimate of growth rate may be expected from open-grown trees. Using regression equations developed from the data, a theoretical conversion to lumber was made for a butt log from an open-grown tree. For boards, graded under the Western Pine Association's rules, it was shown that large knots may degrade lumber grown at the maximum rate. Therefore, use of an open-to-normal density model, which allows crowns to compete before excessive knot formation occurs, would be a desirable objective for management of lodgepole pine.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| 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 | 0,000 | 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) | 0,000 | 0,000 |
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 tête enseignante, 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 ».