Establishment of drip-irrigated poplar in semi arid British Columbia
Notice bibliographique
Résumé
The need for research into systems that augment diminishing wood fibre supplies is underscored by escalating pressures on primary forests. In semi-arid forest plantations, small-scale site preparation can reduce competition from non-crop species, but interplanting amongst existing vegetation may create favorable establishment conditions including altered soil water content and hindered deer browsing. The objectives of this thesis are to determine: (1) the impact of mechanical site preparation versus interplanting on the survival and initial growth of Populus cuttings, (2) differences in survival and initial growth between four different selectively-bred Populus clones and (3) whether there is an interaction between the establishment treatments and the different clones in an intensively managed plantation. In 2016, a drip irrigation system was constructed to deliver approximately 2.5 l day-1 of water to cuttings of 4 selectively-bred poplar (Populus deltoides x petrowskyana (P. laurifolia x P. nigra)) clone types (Green Giant, Griffin, Hill, Walker) planted across 6 blocks in a 10-hectare plantation on Skeetchestn Reserve west of Kamloops, BC. Before planting, 50% of each block was treated with mechanical site preparation, and 50% was not mechanically site prepared to allow for interplanting of the cuttings with existing vegetation. Watering took place from July-September 2016 and from May-September 2017. In 2016, trees were watered for 48 days, totaling 1.06 x 106 l. In 2017, trees were watered for 96 days, totaling 2.12 x 106 l. At the end of each growing season, non random sampling including measurements of basal diameter, total height and length of longest stems as well as counts of tree survival were conducted. Generalized linear models were constructed to investigate responses of survival, diameter, height and volume index to establishment treatment, clone type and initial cutting size predictors. Significant differences in tree survival, basal diameter, basal diameter increment, total tree height, total tree height increment, volume index and volume index increment were found between clones (p<0.05) but not between establishment treatments after the first (2016) and second growing season (2017). No significant treatment*clone interactions were detected. By fall 2017, the best performing clone was Green Giant with 75% survival, 15.6 mm basal diameter, 0.6 mm two-year diameter increment, 43.6 cm height, 14.3 cm two-year height increment, 0.10 dm3 volume index and 0.06 dm3 two-year volume index increment. The worst performing clone was Griffin with 32% survival, 12.0 mm basal diameter, 0.2 mm two-year diameter increment, 38.7 cm height, 4.9 cm two-year height increment, 0.06 dm3 volume index and 0.03 dm3 two-year volume index increment. Cuttings with larger initial diameters exhibited significantly better (p<0.05) survival, diameter increment, height increment and volume index increment in the first year after planting. With first year survival being paramount to establishment success, cuttings planted in similar conditions should be selected for large basal diameters. The mechanical site preparation establishment treatment showed consistent improvement of establishment and growth parameters over the interplanting treatment, but mixed significant (p<0.05) and non-significant (p>0.05) results did not support recommending it for future use.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
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 | 0,001 | 0,001 |
| Études des sciences et des technologies | 0,002 | 0,001 |
| Communication savante | 0,001 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 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 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 ».