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Defoliation level and site type are thought to influence tree response during spruce budworm (Choristoneura fumiferana (Clemens)) outbreaks. We determined the effects of four manual defoliation treatments (0%, 50%, 100%, and 100% + bud removal of current foliage) for 3 years on foliage production of balsam fir (Abies balsamea (L.) Mill.), black spruce (Picea mariana (Mill.) Britton, Sterns & Poggenb.), and white spruce (Picea glauca (Moench) Voss) trees on four site-quality classes. After 3 years of defoliation and 2 years of recovery, foliage biomass was reduced by 34%-98%. During defoliation, the number of shoots generally increased and shoot length of spruce generally decreased, especially on rich sites. During recovery, the number of shoots increased substantially, shoot length decreased, and bud destruction reduced the number of shoots by about 50% compared with that of trees that received the 100% defoliation treatment. Defoliation did not substantially affect needle length. Trees on rich sites had two- to fourfold greater foliage production than trees on poor sites. Effects of site and defoliation differed among species, but site quality, especially nutrition, played an important role in production of shoots and needles and the tree's ability to withstand defoliation. Black spruce had more limited ability to recover foliage biomass, only producing more shoots, whereas balsam fir and white spruce had stronger ability to recover needle and shoot length, respectively. Key words: Choristoneura fumiferana, manual defoliation, foliage biomass. On croit que l'intensite de la defoliation et le type de station influencent la reaction des arbres lors des epidemies de tordeuse des bourgeons de l'epinette (Choristoneurafumiferana (Clemens)). Nous avons determine les effets de quatre traitements de defoliation manuelle (0, 50,100% et 100% + destruction des bourgeons du feuillage de l'annee en cours) pendant trois ans sur la production de feuillage chez des tiges de sapin baumier (Abies balsamea (L.) Mill.), d'epinette noire (Picea mariana (Mill.) Britton, Sterns & Poggenb.) et d'epinette blanche (Picea glauca (Moench) Voss) sur des stations de quatre classes de qualite. Apres trois annees de defoliation et deux annees de recuperation, la biomasse du feuillage a ete reduite de 34 a 98%. Durant la periode de defoliation, le nombre de pousses a generalement augmente et la longueur des pousses de l'epinette a generalement diminue, particulierement sur les stations riches. Durant la periode de recuperation, le nombre de pousses a augmente de facon importante, la longueur des pousses a diminue et la destruction des bourgeons a reduit d'environ 50% le nombre de pousses comparativement au traitement de defoliation a 100%. La defoliation n'a pas eu d'impact important sur la longueur des aiguilles. Les arbres situes sur les stations riches ont produit deux a quatre fois plus de feuillage que sur les stations pauvres. Les effets de la station et de la defoliation differaient selon l'espece mais la qualite de la station, particulierement la nutrition, jouait un role important dans la production de pousses et d'aiguilles et la capacite des arbres a supporter la defoliation. L'epinette noire avait une capacite plus limitee de recuperer la biomasse foliaire; elle produisait seulement plus de pousses tandis que le sapin baumier et l'epinette blanche avaient respectivement une plus grande capacite de recuperer les aiguilles et la longueur des pousses. [Traduit par la Redaction] Mots-cles: Choristoneura fumiferana, defoliation manuelle, biomasse foliaire., 1. Introduction During spruce budworm (Choristoneura fumiferana (Clemens)) outbreaks, larvae repeatedly consume current-year foliage of balsam fir (Abies balsamea (L.) Mill.) and species of spruce (Picea A. Dietr.), leading to [...]

Measures of forest productivity generally rely on site index, which can be problematic for multicohort and mixed-species stands. Using stand growth and dominant tree height-age (i.e., site tree) measurements from ~10 900 plot locations from Maine, Nova Scotia, New Brunswick, and Prince Edward Island, a forest productivity model for the Acadian Forest Region was developed as a function of climate, lithology, soils, and topographic metrics. Approximately 65% of variation in observed aboveground dry-biomass growth rate (BG) was explained by a Chapman-Richards function of temperature, bedrock, soil root space, slope, and depth to water in combination with stand structure and species predictors. Productivity was then defined in terms of the predicted asymptote of BG, holding structure and species constant, which was termed biomass growth index (BGI), i.e., the site-influenced component of the BG relationship. BGI was mapped on a 20 m grid throughout the region. BGI explained 0%-30% of the variability in spruce (Picea sp.) and balsam fir (Abies balsamea (L.) Mill.) site index and had similar site index predictive performance (± 5%) when compared with existing land productivity classifications in each province. BGI provides a direct relationship between site variables and growth and can help guide forest management decisions and future research. Key words: productivity, mixed species, site index, Acadian Forest Region, biomass growth. Les mesures de productivite forestiere reposent generalement sur l'indice de qualite de station, ce qui peut etre complique dans le cas des peuplements comportant plusieurs cohortes ou especes d'arbres. A l'aide de mesures de croissance des peuplements et de la relation entre la hauteur et l'age de l'arbre dominant (c.-a-d. l'arbre de la station) prises dans 10 900 placettes du Maine, de la Nouvelle-Ecosse, du Nouveau-Brunswick et de l'ile-du-Prince -Edouard, un modele de productivite forestiere a ete mis au point pour la region forestiere acadienne en fonction de mesures portant sur le climat, la lithologie, les sols et la topographie. Environ 65 % de la variation observee du taux de croissance en biomasse seche aerienne (CB) etait explique par une fonction de Chapman-Richards prenant en compte la temperature, la roche mere, l'espace racinaire du sol, la pente et la profondeur de la nappe phreatique en combinaison avec des variables associees a la structure des peuplements et aux especes. La productivite a ensuite ete definie en termes d'asymptote predite de la CB, de la structure permanente et de la constante par espece pour former l'indice de croissance en biomasse (ICB). Cet indice correspond a la composante de la relation de la CB qui est influencee par la station. L'ICB a ete cartographie a une resolution de 20 m pour l'ensemble de la region. L'ICB expliquait de 0 a 30 % de la variation de l'indice de qualite de station pour les epinettes (Picea sp.) et le sapin baumier (Abies balsamea (L.) Mill.), et sa capacite predictive de l'indice de qualite de station etait similaire (± 5 %) a celle des classifications de productivite territoriale disponibles dans chaque province. L'ICB fournit une relation directe entre les variables de la station et la croissance, et peut aider a orienter les decisions d'amenagement forestier et les futures pistes de recherche. [Traduit par la Redaction] Mots-cles: productivite, especes mixtes, indice de qualite de station, region forestiere acadienne, croissance en biomasse., Introduction Determining site productivity is an important yet difficult issue for forest management and planning (e.g., Carmean 1975; Skovsgaard and Vanclay 2008, 2013). A variety of direct and indirect, as [...]

Silvicultural treatments recommended to reduce damage by spruce budworm (SBW; Choristoneurafumiferana Clemens) include reducing balsam fir (Abies balsamea (L.) Mill.) abundance and age and increasing spruce (Picea spp.) and hardwood content. To evaluate the effect of these measures on forest timber supply, we assessed stand characteristics, disturbance history, and timber supply for an intensively managed eastern Quebec forest from 1985 to 2004, encompassing a major SBW outbreak. During this time, mean stand age declined from 55 to 51 years, and proportions of areas in balsam fir stands declined (42% to 27%), spruce-fir stabilized (12% to 11%), and mixedwoods increased (32% to 52%). We estimated forest vulnerability using softwood volume reductions following simulated outbreak scenarios of different severity (low, moderate, and high) and different effects of hardwood content in reducing spruce-fir defoliation. Volume reductions for outbreaks simulated to begin in either 1985 or 2004 were similar, ranging from 15%-46% (no hardwood effect in reducing defoliation) to 13%-39% (given a maximum hardwood content effect) for light and severe outbreaks, respectively. Considering the net detrimental effect of increased hardwood content on softwood timber supply, we question the dividends of promoting hardwoods and recommend increasing the combined use of plantations and weeding treatments to increase spruce content. Key words: spruce budworm outbreak, silviculture, protective effects of hardwoods, softwood timber supply, forest protection. Les traitements sylvicoles recommandes pour reduire les dommages lors d'epidemies de la tordeuse des bourgeons de l'epinette (TBE; Choristoneurafumiferana Clemens) incluent la reduction de l'abondance et de l'age du sapin (Abies balsamea (L.) Mill.) et l'augmentation de l'abondance d'epinettes (Picea spp.) et de feuillus. Afin d'evaluer l'effet de ces mesures sur l'approvisionnement en bois, nous avons evalue de 1985 a 2004 les caracteristiques, l'historique des perturbations et l'approvisionnement en resineux d'une foret de l'est du Quebec sous amenagement intensif et pendant une epidemie majeure de TBE. Pendant cette periode, l'age moyen des peuplements a chute de 55 a 51 ans, la proportion de peuplements de sapin a chute (42 % a 27 %), celle d'epinette-sapin s'est maintenue (12 %a 11 %) et celle mixte a augmente (32 % a 52 %). La vulnerabilite des forets a ete estime a partir des reductions de volume resineux suivant des simulations d'epidemies de differentes severite (faible, moderee et severe) et effet des feuillus sur la reduction de la defoliation des hotes. Les pertes de bois des epidemies debutant en 1985 ou 2004 se sont averees similaires et s'elevaient de 15 %-46 % (aucun effet des feuillus) a 13 %-39 % (effet des feuillus maximal) pour les epidemies legeres et severes. Etant donne la difficulte d'augmenter l'abondance d'epinettes et les pertes nettes de production resineuse liees au contenu eleve en feuillus, nous remettons en question les benefices lies a la preservation des feuillus et recommandons une utilisation accrue du controle de la vegetation en plantation pour augmenter l'abondance d'epinette. Mots-cles : epidemie de tordeuse des bourgeons de l'epinette, sylviculture, effet de protection des feuillus, approvisionnement en bois resineux, protection des forets., Introduction The last spruce budworm (Choristoneura fumiferana Clemens; SBW) outbreak, which occurred from 1967 to 1992 in eastern Canada and in the United States (US), generated an estimated annual loss [...]

: We investigated the potential economic impacts of future spruce budworm (SBW) (Choristoneura fumiferana (Clemens)) outbreaks on 2.8 million hectares of Crown forest land in New Brunswick by coupling an advanced Spruce Budworm Decision Support System (SBW DSS) model with a dynamic computable general equilibrium model. A total of 16 alternative scenarios were evaluated, including two SBW outbreak severities (moderate versus severe), four SBW control program levels (protecting 0%, 10%, 20%, and 40% of susceptible Crown land forest area), and two pest management strategies ('without' versus 'with' replanning harvest scheduling and salvage). The 'without' replanning harvest scheduling and salvage strategy findings indicated that, under uncontrolled moderate and severe SBW outbreaks, total output in the New Brunswick economy over the 2012-2041 period would decline in present-value terms by CDN$3.3 billion and $4.7 billion, respectively. SBW control via aerial spraying was shown to reduce the negative impacts on output by up to 66% when protecting 40% of susceptible area. Combining SBW control with replanning harvest scheduling and salvage strategy under moderate and severe outbreaks would reduce the negative impacts on output by a further 1%-18% depending on the level of control implemented. These findings can help forest managers assess the direct and indirect economic effects of forest pest disturbances on regional economies and can also be used together with other sustainable forest management indicators to help broaden the scope of SBW and other forest pest management decision-making. Resume: Nous avons examine les impacts economiques potentiels de futures epidemies de tordeuse des bourgeons de l'epinette (TBE) (Choristoneura fumiferana (Clemens)) sur 2, 8 millions d'hectares de forets publiques au Nouveau-Brunswick en couplant un modele sophistique d'aide a la decision pour la TBE avec un modele dynamique d'equilibre general qui peut etre calcule. Un total de 16 scenarios differents ont ete evalues, incluant deux niveaux de severite d'epidemie de TBE (moderee versus severe), quatre intensites de programmes de lutte (protection de 0 %, 10 %, 20 % et 40 % de la superficie forestiere a risque sur les terres publiques) et deux strategies de gestion des ravageurs (avec et sans replanification du calendrier de recolte ni coupe de recuperation). Les resultats associes a la strategie qui ne comporte pas de replanification du calendrier de recolte ni de coupe de recuperation indiquent que, dans le cas d'epidemies moderees et severes non reprimees de TBE, la production totale de l'economie du Nouveau-Brunswick durant la periode 2014-2041 diminuerait en valeur actualisee de respectivement CDN3, 3 $ milliards et 4,7 $ milliards. Le recours aux arrosages aeriens pour lutter contre la TBE pourrait reduire jusqu'a 66 % les impacts negatifs sur la production en protegeant 40 % de la superficie a risque. En cas d'epidemies moderees et severes, la strategie qui combine la lutte contre la TBE avec la replanification du calendrier de recolte et la coupe de recuperation reduirait les impacts negatifs sur la production dans une proportion additionnelle de 1 % - 18 % dependamment du niveau de lutte mis en oeuvre. Ces resultats peuvent aider les amenagistes forestiers a evaluer les effets economiques directs et indirects des perturbations causees par les ravageurs forestiers sur les economies regionales et peuvent aussi etre utilises avec d'autres indicateurs d'amenagement forestier durable pour aider a elargir la portee du processus de prise de decision pour gerer la TBE et d'autre ravageurs forestiers. [Traduit par la Redaction], Introduction The forest sector plays a significant role in the Canadian economy. It directly contributes approximately CDN$51 billion in annual output (3% of total), directly or indirectly employs more than [...]

: An integrated forest management optimization model was developed to calculate potential spruce budworm (Choristoneura fumiferana Clemens) effects on forest and wood product carbon (C) from 2007 to 2057 and to evaluate potential C sequestration benefits of alternative management strategies (salvage, biological insecticide application). The model was tested using simulated spruce budworm outbreaks on a 210 000 ha intensively managed forest in northwestern New Brunswick, Canada. Under a severe spruce budworm outbreak scenario from 2007 to 2020, harvest volume and forest and wood product C storage in 2027 were projected to be reduced by 1.34 [Mm.sup.3], 1.48 Mt, and 0.26 Mt, respectively, compared with the levels under no defoliation. Under the same severe outbreak scenario, implementation of salvage and harvest replanning plus a biological insecticide applied aerially to 40% of susceptible forest area, reduced harvest, forest C, and wood product C impacts by 73%, 41%, and 56%, respectively. Extrapolation of these results to all of New Brunswick suggests that a future severe spruce budworm outbreak could effectively increase total provincial annual C emissions (all sources) by up to 40%, on average, over the next 20 years. This modeling approach can be used to identify to what extent insecticide application, as a forest-C-offset project, could result in additional C storage than without forest and pest management. Resume: Un modele integre d'optimisation de l'amenagement forestier a ete developpe pour calculer les effets potentiels de la tordeuse des bourgeons de l'epinette (Choristoneura fumiferana Clemens) sur le carbone (C) forestier et celui des produits du bois de 2007 a 2057 et evaluer les benefices de strategies alternatives d'amenagement (coupe de recuperation, application d'insecticide biologique) sur la sequestration potentielle du C. Le modele a ete teste en ayant recours a des epide mies simulees de tordeuse des bourgeons de l'epinette dans une foret de 210 000 ha amenagee de facon intensive dans le nord-ouest du Nouveau-Brunswick, au Canada. Comparativement a l'absence de defoliation, un scenario impliquant une epidemie severe de tordeuse des bourgeons de l'epinette de 2007 a 2020, reduirait de respectivement 1,34 [Mm.sup.3], 1,48 Mt et 0,26 Mt le volume de recolte et le stockage du C en foret et dans les produits du bois en 2027. Dans le meme contexte d'une epidemie severe, le recours a la coupe de recuperation et a la replanification de la recolte en plus de l'application aerienne d'un insecticide biologique sur 40 % de la superficie de foret vulnerable a reduit de respectivement 73, 41 et 56 % les impacts sur la recolte, le C forestier et celui des produits du bois. L'extrapolation de ces resultats a l'ensemble du Nouveau-Brunswick indique que dans l'avenir une epidemie severe de tordeuse des bourgeons de l'epinette pourrait effectivement augmenter jusqu'a 40 % en moyenne les emissions annuelles totales (toutes les sources) de C de la Province au cours des 20 prochaines annees. Cette approche de modelisation peut etre utilisee pour determiner dans quelle mesure l'application d'insecticide pour reduire les pertes de C forestier pourrait se traduire par un stockage additionnel de C comparativement a une situation ou il n'y aurait ni amenagement de la foret, ni gestion des ravageurs. [Traduit par la Redaction], Introduction Heightened pressure to reduce Canada's greenhouse gas emissions has amplified the need for reliable information to identify forest management and protection contributions toward forest carbon (C) sequestration. Conceivable contributions [...]

We describe a procedure to maximize carbon (C) sequestration and apply it to a 428 000 ha industrial forest management area in northern New Brunswick, Canada. Stand-specific C yield tables and C residency periods in harvested wood products were used as inputs to a linear programming model to maximize on- and off-site C sequestration in forest land. Five management scenarios were evaluated. A scenario that maximized on-site forest C sequestration for 80 years, respecting 'business-as-usual' harvest constraints, projected an extra 3 t C x [ha.sup.-1] across the forest management area compared with the business-as-usual scenario, with net C storage potential (forest C + forest C in products-emissions produced from decayed wood products) resulting in approximately 1 Mt C. A scenario to double softwood harvest led to a projected decrease in the forest C pool by approximately 5 t [C x [ha.sup.-1] from 2007 to 2082 and overall storage decrease of almost 2 Mt C from the base run. Other scenarios to increase or decrease harvest volumes by 10% resulted in overall C storage increases of 1.6 Mt C and almost 2.7 Mt C, respectively, above the base run. All scenarios resulted in net sinks of C after the 80 year simulation. Nous decrivons une procedure pour maximiser la sequestration du carbone (C) et nous 1' appliquons a une super-ficie de foret industrielle amenagee de 428 000 ha dans le nord du Nouveau-Brunswick, an Canada. Des tables de rendement en C specifiques a chaque peuplement et des periodes de residency de C dans les produits du bois recoltes ont ete utilisees comme intrants dans un modele de programmation lineaire pour maximiser la sequestration de C dans et a 1'exterieur des sites sur un territoire forestier. Cinq scenarios d' amenagement ont ete evalues. Un scenario qui maximise la sequestration de C sur place en foret pendant 80 ans, ce qui respecte les contraintes courantes de recolte, a produit 3 t de C x [ha.sup.-1] supplementaires dans la zone d' amenagement forestier, comparativement an scenario habituel, avec une possibilite de stockage nette de C (C en foret + C dans les produits forestiers--les emissions dues a la decomposition des produits du bois) d'environ 1 Mt de C. Un scenario consistant a doubler la recolte des resineux a entrame une diminution projetee des reserves de C en foret d'environ 5 t de C x [ha.sup.-1] de 2007 a 2082 et une diminution globale du stockage de presque 2 Mt de C par rapport an scenario de reference. Les autres scenarios qui consistaient a augmenter on diminuer le volume de recolte de 10% ont entraine des augmentations globales du stockage de respectivement de 1,6 Mt de C et de presque 2,7 Mt de C par rapport an scenario de reference. Tons les scenarios ont engendre un puits net de C apres la periode de simulation de 80 ans. [Traduit par la Redaction], Introduction With recent international treaties aimed at reducing greenhouse gases, forests and forest products and their roles in global carbon (C) cycle have gained importance in terms of public awareness [...]

Abstract: Spruce budworm (Choristoneura fumiferana Clem.) severely defoliates balsam fir (Abies balsamea (L.) Mill.) and spruce (Picea spp.) in large periodic outbreaks and represents one of Canada's most damaging and [...]

Aerial survey records of defoliation by spruce budworm (Choristoneura fumiferana (Clem.)) in New Brunswick, Canada taken annually from 1965 to 1992, were analyzed at four scales (66 x 66 km, 10 x 10 km, 2 x 2 km, 1 x 1 km) to determine patterns and spatial variability of defoliation. Spruce budworm defoliated 92% of the 7.4 million ha study area in at least one year. Cluster analysis was used to group similar defoliation patterns, and 51% of the variation in the 28-year record was described by 28 representative defoliation patterns, at 1 x 1 km cell size. Individual defoliation patterns were grouped into five spruce budworm outbreak classes (termed A-E), which each covered 12-27% of the area. These differed substantially in defoliation duration and severity: classes A-B had only 1-3 years of moderate-severe defoliation and 42-75% cumulative defoliation; class C had 8 years and 127% cumulative defoliation; and classes D-E had 13-16 years and 170-208% cumulative defoliation. Given the degree of 'averaging out' of high defoliation occurrences that cause the largest impacts, larger 10 x 10 km and 66 x 66 km cells were inappropriate for impact analysis. Defoliation variability was highest at 20-60% mean defoliation than at lower or higher defoliation levels. Distributions of area in each class in 1 x 1 km cells for 66 x 66 km areas throughout the province showed that with the exception of several small coastal areas, four or five of the above outbreak classes occurred in all areas. The wide variation in spruce budworm outbreak patterns is important in making management decisions that differentiate insecticide or salvage treatments based on defoliation severity, and emphasizes the importance of accurate annual aerial survey or remote sensing-based defoliation assessment. [ABSTRACT FROM AUTHOR]

Spruce budworm (SBW) infestations and defoliation in forests of eastern North America (e.g., 1910s, 1940s, and 1970 -1980s) have had significant negative impacts on growth and survival of spruce and fir. The Spruce Budworm Decision Support System (SBWDSS), originally developed by the Canadian Forest Service, can assist with SBW management planning by estimating the marginal timber supply (in cubic meters per hectare) benefits of protecting stands against budworm defoliation. We applied the SBWDSS to Maine and for two private forests (≈10,000-ha townships) to assess potential spruce-fir losses. Application of the approach across diverse forest types and data sets revealed dramatic differences in potential volume impacts between the two townships. The statewide analysis suggested that over 4 million ha of Maine's forest are vulnerable to the budworm. Projections of moderate and severe intensity outbreaks reduced statewide spruce-fir inventories by 20 -30% over the next 10 years. [ABSTRACT FROM AUTHOR]