A spacing trial was established near Thunder Bay, Ontario in Une plantation a kt6 kalisk B titre exphimental prbs de Thunder 1950. This trial consisted of black spruce (Picea rnariana (Mill.) Bay en Ontario en 1950. Cet essai portait sur l'kpinette noire B.S.P.), white spruce (Picea glauca (Moench) Voss.), and red pine (Picea mariana (Mill.) B.S.P.), l'kpinette blanche (Picea glauca (Pinus resinosa Ait.) each established at three different spacings:(Moench) Voss.), et le pin rouge (Pinus resinosa Ait.) chacune des 1.8 m, 2.7 m, and 3.6 m. This study examines the differences in e s e e s plant& selon trois espacements: 1.8 m, 2.7 et 3.6 m Cette growth and crown development as attributed to initial spacing, after ktude se penche sur les diffkrences en croissance et en dkveloppe-37 years. In addition, a benefivcost analysis was performed to evalment de la cime en fonction de l'espacement initial, 37 ans plus tard. uate the economic efficiency of the various species/spacing comDe plus, une analyse des Mnkfices en fonction des coats a kt6 effecbinations. Diameter at breast height, live crown length, and tuCe afin d'kvaluer l'efficacite kconomique de diffkrentes combicrown width, all exhibited significant (P < 0.001) increases as ini-tial spacing increased, irrespective of species, but, height demonpoitrine, la longueur de la cime vivante et le diambtre de la cime ont strated a decreasing trend (P < 0.020). Gross total and mertous dkmontd des augmentations significatives (P < 0.001) en foncchantable stem volume per tree increased for all species as initial tion de l'augmentation de l'espacement initial, pour toutes les spacing increased; however, volume production per unit area espbces, mais la hauteur suivait une tendance inverse (P < 0.020). decreased significantly for all species as spacing increased. The shift Le volume total et le volume marchand par arbre a augment6 pour to higher-valued products from the wider-spaced plantations toutes les esp2ces B mesure que s'accroissait l'espacement initial, appeared to provide the best economic return. As a result of both alors que le volume par unit6 de surface diminuait significativement greater merchantable volumes and greater percentages of these volpour toutes les esp&ces en fonction de l'augmentation de l'espaceumes available as a higher-valued product, benefitlcost ratios for ment. Le changement vers des produits de plus grande valeur tirks red pine (0.995 to 1.337) were greater than those for the spruces des plantations B espacement plus grand semble procurer le meilleur (0.595 to 0.866). Although red pine currently represents less than retour sur l'investissement. Les ksultats B la fois au niveau des vol-4% of Ontario's total regeneration effort, the results from this study umes marchands supkrieurs et du plus fort pourcentage de ces suggest it deserves further consideration on some boreal sites.volumes disponibles en tant que produit de valeur supkrieure ont permis d'obtenir des ratios des b6n6fices en fonction des coats pour Key words: spacing trial, plantat...
In 1986, a thinning trial was established in a 9-year-old jack pine stand near Dryden, Ontario. Four blocks consisting of five thinning regimes (1 m × 1 m, 1.5 m × 1.5 m, 2 m × 2 m, 2.5 m × 2.5 m, 3 m × 3 m) and a control plot were established using a randomized complete block design. Once thinned, a series of measurements were taken in 1986 and repeated in 1991 to determine growth and form responses. Results identified highly significant responses for DBH growth and individual stem volume growth. Height response did not vary among the spacing levels. Changes in crown dimensions and stem taper were used to evaluate form responses to thinning. A highly significant decline in all form variables was found in response to increased spacing. Although the increased growth in individual trees provides an opportunity to produce a wider array of products, it appears to be at a cost of reduced form characteristics. Specific management implications for the Dryden Crown Forest are discussed. Key words: jack pine, pre-commercial thinning, growth and form responses
Jack pine (Pinus banksiana Lamb.) is one of the most imporLe pin gris (Pinus banksiana Lamb.) constitue l'une des printant commercial species in northwestern Ontario and is the principales espbces commerciales du nord-ouest de l'ontario en cipal host of one of the most serious stem rusts, western gall rust plus d'&tre l'h6te de la plus importante des rouilles du tronc, la (WGR) caused by Endocronartium harhssii (J.P. Moore) Y. Hirat.rouille-tumeur globuleuse (RTG) provoquCe par Endocronartium In 1986 a trial was established to determine, in part, effects of preharknessii (J.P. Moore) Y. Hirat. Un essai a Ct C effectue en commercial thinning on the distribution and occurrence of WGR 1986 afin de determiner, d'une part, les effets de 1'Cclaircie prCin jack pine. A 9 year-old aerially seeded jack pine stand was thinned commerciale sur la distribution ainsi que la prCsence de la RTG to square spacings of 1 m, 1.5 m, 2 m, 2.5 m, 3 m and a control. dans les peuplements de pin gris. Un peuplement &gC de neuf ans Fifth-year results indicated that a significant quadratic trend issu d'un ensemencement aCrien a 6tC Cclairci selon des espace-( p = 0.014) existed between spacing and stem gall infection ments carrCs de 1 m, de 1.5 m, de 2 m, de 2.5 m, et de 3 m tout rate. The incidence of WGR (stem galls) increased as stand denen conservant une parcelle-tCmoin. Les rksultats aprks cinq ans sity decreased to a maximum at 1.5 m spacing, and then declined indiquent qu'une relation quadratique significative (P = 0.014) to roughly the infection rate of the control at the lowest density existe entre l'espacement et le taux d'infection par la rouille. Le (3 m). A significant relationship (0.084) between crown class and taux d'infection de la RTG (turneurs de tige) a augment6 alors que the rate of branch gall infection rate was also detected. The la densit6 du peuplement diminuait passant d'une valeur maxibranch gall infection rate decreased from 6.2% year1 for dommale ? i un espacement de 1.5 m, pour par la suite diminuer pour inant trees to 2.8% year1 for trees categorized as suppressed. Based atteindre B peu pr&s le taux d'infection du tCmoin au niveau de la on these results, pre-commercial thinning operations should tardensit6 la plus faible (3 m). Une relation significative (0.084) entre get those trees with main stem galls andlor numerous branch galls, la claw de cime et le niveau &infection ptn la tumeur sur les branchregardless of size and crown position, and then focus on the removal es a Cgalement Ct C dCtectCe. Le niveau d'infection par la tumeur of suppressed trees to meet the desired density target. This stratsur les branches a diminuC de 6.2% par an pour les arbres domegy should not only enhance growth of the remaining trees, but inants et de 2.8% par an pour les arbres de la classe dominee. En also reduce WGR inoculum levels and reduce future WGRfonction de ces rCsultats, les opCrations d'kclaircie prkcommerrelated mortality.ciale devraient viser les arbres dont le tronc principal etlou plusieurs branches sont infect& ...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.