Chemical, grazing, and manual cutting treatments in mixed herb–shrub communities have no effect on interior spruce survival or growth in southern interior British Columbia

For public lands in Canada, the free-to-grow (FTG) standards are part of regulatory surveys of post-harvest juvenile stands that are designed to assess the level of competition on conifer trees. In this paper we analyzed two data sets to test the ability of FTG standards to predict growth of white spruce saplings. Using data from juvenile permanent sample plots, FTG was assessed at age 13 and subsequent diameter increment and height increment were assessed in the measurement interval after year 18. If the growth of trees was adjusted for differences in height at age 13, FTG status made no difference in predicting subsequent growth. A second data set from operational regeneration surveys of 49, 13-year-old boreal mixedwood stands was also evaluated for evidence of competition across a range of cutblock with different percentages of plots classed as FTG. There was no evidence of an increase in variation in size or growth of leading trees in stands when the plots in a cutblock were evenly split between FTG and not-FTG trees, compared to cutblocks with either few plots FTG or nearly all plots FTG. Height attained at year 13 was a sufficient indicator of future growth. Key words: regeneration, standard, free, grow, productivity, mixedwoods

Section: Interceptmentioning

confidence: 99%

Free-to-grow regeneration standards are poorly linked to growth of spruce in boreal mixedwoods

Lieffers¹,

Stadt²,

Zhang³

2007

“…by vegetation management limit conifer growth (Heineman et al 2005). Although this information provides evidence that effective conifer release treatments will consistently increase conifer survival and growth when competition for resources is a limiting factor, it is insufficient for forest managers to predict future stand yields.…”

Section: Introductionmentioning

confidence: 99%

Longer-Term Volume Trade-offs in Spruce and Jack Pine Plantations Following Various Conifer Release Treatments

Wayne

DacostaJennifer

PennerMargaret³

et al. 2011

We assessed growth responses 10 years post treatment for 31 combinations of site, species, and treatments from six studies in Ontario, Canada, to determine if conifer release treatments increase gross total conifer volumes but decrease gross total stand volumes in boreal forests. Treatments included single and multiple herbicide application or motor-manual and mechanical conifer release. Treatment effects on 10 th -year gross total preferred conifer and total stand volumes ranged from -49% to +556% and -71% to +116%, respectively, compared to the untreated controls. We projected net merchantable stand volumes (NMV) from 10 years post treatment to 60 years of age. These projections indicate that NMV of preferred conifers at age 60 could range from 7.4 m 3 ha -1 to 232.4 m 3 ha -1 . The variation in observed and predicted volumes can be attributed to site characteristics, tree species, ecology, and treatment efficiency.Keywords: forest vegetation management, growth and yield, Picea mariana, Picea glauca, Pinus banksiana, herbicides, motor manual cutting résumé Nous avons analysé les réactions, en termes de croissance 10 ans après traitement, décrites dans six études effectuées en Ontario, au Canada, totalisant 31 combinaisons de stations, d' espèces et de traitements, afin de déterminer si les traitements de dégagement des conifères ont permis, en forêt boréale, un accroissement du volume brut total des conifères mais une diminution du volume brut total des peuplements. Les traitements comportaient une application simple et une application multiple de phytocide ou un dégagement au moyen d' outil motorisé individuel et un dégage-ment mécanisé. Les effets des traitements sur le volume brut total des conifères sélectionnés et sur le volume total des peuplements à la 10e année ont varié respectivement de -49% a +556% et de -71% à +116%, comparativement aux superficies témoins non traitées. Nous avons projeté les volumes marchands nets (VMN) des peuplements 10 ans après traitement jusqu'à l'âge de 60 ans. Ces projections indiquent que les VMN des conifères sélectionnés à l'âge de 60 ans pourraient varier de 7,4 m3 ha-1 à 232,4 m3 ha-1. Les variations entre les volumes mesurés et prédits peuvent être attribuées aux caractéristiques de la station, à l' espèce, à l' écologie et à l' efficacité du traitement.

“…Forest vegetation management practices include several alternatives (Wiensczyk et al 2011, this issue) and results from experimental studies on growth rates and volume production are highly variable among these alternative treatments (Comeau et al 1999;Simard et al 2001;Heineman et al 2005;Bell et al 2011a, this issue). The costs associated with the various treatments also vary greatly , Dampier et al 2006.…”

Section: Introductionmentioning

confidence: 99%

Benefit–cost Analysis of Vegetation Management Alternatives: An Ontario Case Study

Luckai

Homagain

Shahi

et al. 2011

Vegetation management practices are an integral component of forest management. In this paper, we report results of stand-level benefit-cost analyses of 12 vegetation management treatments applied at six study sites in northern Ontario. Forest Vegetation Simulator (FVS Ontario ) was used to project gross total and merchantable volumes to 70 years of age, and BUCK-2 was used to optimize potential products. Net present value (NPV), benefit-cost ratio (BCR), and internal rate of return (IRR) were calculated using 2009 constant dollars and variable real discount rates. Aerial herbicide treatments produced the highest NPV, BCR, and IRR. Internal rates of return of 4.32%, 2.90%, 2.82% and 2.50% for aerial herbicide, manual brush cutting, ground-applied herbicide, and brush cutting plus herbicide treatments, respectively, indicated that all of the vegetation management alternatives evaluated are economically viable.Key words: aerial herbicides, brush saw, forest economics, Forest Vegetation Simulator (FVS Ontario ), ground herbicides, internal rate of return, net present value RÉSUMÉ Les pratiques de contrôle de la végétation font partie intégrante de l'aménagement forestier. Dans cet article, nous reportons des résultats obtenus par des analyses de coût-bénéfice effectuées au niveau du peuplement pour 12 traitements de contrôle de la végétation appliqués sur six sites d' études du nord de l'Ontario. Le Forest Vegetation Simulator (FVSOntario) a été utilisé pour projeter le volume total et le volume marchand à l'âge de 70 ans et le BUCK-2 a été utilisé pour optimiser les produits potentiellement obtenus. La valeur actuelle nette (VAN), le ratio coût-bénéfice (RCB) et le taux de rentabilité interne (TRI) ont été calculés en dollars constants de 2009 et selon des taux variables de profitabilité réelle. L' épandage aérien de phytocide a généré les VAN, RCB et TRI les plus importants. Les taux de rentabilité interne de 4,32 %, 2,90 %, 2,82 % et de 2,50 % respectivement pour l' épandage aérien, le débroussaillage manuel, l'application terrestre de phytocide et le débroussaillage manuel suivi de traitements de phytocide, ont démontré que toutes les alternatives de contrôle de la végétation évaluées sont économiquement viables.Mots clés : épandage aérien de phytocide, débroussailleuse, économie forestière, Forest Vegetation Simulator (FVSOntario), épandage terrestre de phytocide, taux de rentabilité interne, valeur actuelle nette