Effects of aerial strip spraying on mixedwood stand structure and tree growth

Abstract

Herbicide application in strips offers a cost-effective way to accelerate spruce growth in young mixedwood stands, while also retaining the mixedwood character of the stand. In June of 2006 data were collected to evaluate the effects of aerial strip spraying on subsequent growth of treated stands. These blocks had been planted in 1991 and treated in 2000 with Triclopyr ester herbicide applied in strips. Treated and untreated strips averaged 5.8 m and 8.4 m in width, respectively, with 38% of the block area being effectively treated. In 2006 aspen density, DBH, and height were significantly lower in the treated strips compared to either untreated strips or completely untreated blocks. Spruce growth was significantly larger in treated strips with diameter growth responses beginning in the first and height growth responses in the second growing season following treatment. Yield estimates from the Mixedwood Growth Model (MGM) indicate that the strip spray treatments result in the highest spruce yields. However, when understory protection (harvesting aspen at age 70 and spruce at 120) is applied, the untreated blocks provided higher total yield and net present value.Keywords: white spruce, trembling aspen, boreal mixedwoods, triclopyr, strip spray, yield , la densité, le dhp et la hauteur des trembles ont été significativement moindres dans les bandes traitées comparativement aux bandes intactes ou par rapport aux parcelles non traitées. La croissance des épinettes a été significativement plus importante dans les bandes traitées affichant des réactions au niveau de la croissance en diamètre en premier lieu et en hauteur à la deuxième année de croissance suivant le traitement. Les rendements estimés à partir du modèle de croissance des peuplements mélangés (MGM) indiquent que les traitements de pulvérisation par bandes permettent d' obtenir les plus forts rendements en épinette. Cependant, lorsque la protection du sousétage est retenue (récolte du tremble à l'âge de 70 ans et de l' épinette à 120 ans), les parcelles non traitées ont affiché un rendement total plus élevé et une valeur actualisée nette supérieure.Mots clés : épinette blanche, peuplier faux-tremble, peuplements mélangés nordiques, triclopyr

Plant Community Diversity and Tree Growth Following Single and Repeated Glyphosate Herbicide Applications to a White Spruce Plantation

“…However, the benefits of two herbicide treatments were evident, as diameter in this treatment was nearly double that of the untreated areas 11 years after planting. Other studies have reported consistent findings; for instance, Comeau [33] reported that spruce diameter increment following triclopyr herbicide treatment was 1.8 times that of control plots, while triclopyr treatment increased stem volume index by 1.7 times. Bell et al [28] reported similar increases in spruce volume ten years after aerial triclopyr treatment.…”

Lodgepole pine and trembling aspen mixedwoods: Growth and yield within 22 to 39 year old pine plantations of northern interior British Columbia

“…If aspen is allowed to "catch-up" after brushing, the inevitable competition impacts to planted pine growth and survival will return. Knowledge of how aspen responds to various brushing treatments can be used to help set acceptable thresholds of aspen size and frequency within mixedwood prescriptions (Comeau 2014). …”

Increased forest biomass production in the Nordic and Baltic countries – a review on current and future opportunities

“…and white spruce (Picea glauca (Moench.) Voss), also with 20 % transgressive over-yielding (Kabzems et al 2007;Comeau 2014). Additional gain is expected by combining this approach with e.g.…”