scholarly journals Estimating windthrow risk in balsam fir stands with the ForestGales model

2000 ◽  
Vol 76 (2) ◽  
pp. 329-337 ◽  
Author(s):  
J.-C. Ruel ◽  
S. Meunier ◽  
C. P. Quine ◽  
J. Suarez
Keyword(s):  
Wind Speed ◽  
Abies Balsamea ◽  
Threshold Value ◽  
Balsam Fir ◽  
Site Quality ◽  
Stand Age ◽  
Thinning Intensity ◽  
Wind Exposure ◽  
The Creation ◽  
Number Of Stems

Balsam fir (Abies balsamea (L.) Mill.) forests are inherently vulnerable to windthrow, especially when silvicultural treatments are applied. During recent years, it has become possible to model windthrow risk based on a good understanding of windthrow mechanics. In the present paper, the British ForestGales model has been adapted for balsam fir with data from a winching study in Quebec, Canada. This model calculates the threshold wind speed required to break or overturn the average tree in a stand and then calculates the probability of exceeding the threshold value. Modifications of the equations predicting crown characteristics and overturning resistance were introduced. The effects of age, site quality, wind exposure, thinning and the creation of new edges were assessed. The estimated critical wind speed for overturning and breakage decreases with age but the probability of damage remains low on sheltered sites. The creation of a new edge leads to an increased probability of damage, especially on exposed, highly productive sites. Thinning alone also increases the probability of damage and the magnitude of the increase varies with age and thinning intensity. On highly productive sheltered sites, the effect of thinning becomes especially important when thinning exceeds 35% of the number of stems or when stand age is greater than 70 years for a 35% thinning intensity. Thinning of new edges was also found to further increase the risk of windthrow on the most sheltered, high quality sites.

Estimating forest vulnerability to the next spruce budworm outbreak: will past silvicultural efforts pay dividends?

2015 ◽  
Vol 45 (3) ◽  
pp. 314-324 ◽  
Author(s):  
Guillaume B. Sainte-Marie ◽  
Daniel D. Kneeshaw ◽  
David A. MacLean ◽  
Chris R. Hennigar
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Stand Age ◽  
Disturbance History ◽  
Timber Supply ◽  
Silvicultural Treatments ◽  
Combined Use ◽  
Intensively Managed

Silvicultural treatments recommended to reduce damage by spruce budworm (SBW; Choristoneura fumiferana 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.

Recent impact of fire on high-altitude balsam fir forests in south-central Quebec1This article is one of a selection of papers from the 7th International Conference on Disturbance Dynamics in Boreal Forests.

2012 ◽  
Vol 42 (7) ◽  
pp. 1289-1305 ◽  
Author(s):  
Pierre-Luc Couillard ◽  
Serge Payette ◽  
Pierre Grondin
Keyword(s):  
High Altitude ◽  
Fire Regime ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Stand Age ◽  
Forest Types ◽  
Plant Composition ◽  
White Birch ◽  
South Central

The dynamics of high-altitude balsam fir ( Abies balsamea (L.) Mill.) forests is mainly driven by insect outbreaks and windthrows. However, very little work has been done on the role of fire on the development and maintenance of this ecosystem. In this study, we document the role of fire in the high-altitude balsam fir forests of the Réserve Faunique des Laurentides (RFL), southern Quebec. Sixteen sites were sampled among six different forest types described according to plant composition and fire evidence. At each site, the diameter structure was recorded and stand age was calculated based on tree-ring dating of individual trees and radiocarbon-dated surficial charcoal samples. Fire played a major role in the recent dynamics of high-altitude fir forests in the RFL. Over the last 250 years, nearly 50% of the study area burned during two fire conflagrations, i.e., around 1815 and in 1878. The fires triggered gradual changes in plant composition and forest structure, as shown by a succession of forest types ranging from white birch ( Betula papyrifera Marsh.) to spruce–fir types. Absence of surficial charcoal older than 300 years suggests that high-altitude forests of the RFL area were not subjected to a constant fire regime. It is possible that recent fires were caused by human activity.

Effects of precommercial thinning on the forest value chain in northwestern New Brunswick: Part 3 – Incidence of root and butt decay

2013 ◽  
Vol 89 (04) ◽  
pp. 464-473 ◽  
Author(s):  
Gary Warren ◽  
Patricia Baines ◽  
Jean Plamondon ◽  
Doug G. Pitt
Keyword(s):  
Forest Management ◽  
Value Chain ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Stand Age ◽  
Stem Form ◽  
Green River ◽  
Precommercial Thinning ◽  
Permanent Sample Plots ◽  
Butt Rot

The Green River precommercial thinning (PCT) trials were established between 1959 and 1961 in naturally regenerating balsam fir (Abies balsamea [L.] Mill.)-dominated stands an average of eight years after overstory removal. Three nominal spacings of 4 ft (1.2 m), 6 ft (1.8 m) and 8 ft (2.4 m) were compared to an unthinned control in six replicate blocks. In the fall of 2008, following completion of the ninth sequential evaluation of the study’s 48 permanent sample plots, three of the six replicates were clearcut harvested; butt rot data were collected immediately afterwards. To date, forest management research and goals have focused on the benefits of PCT, such as increased tree size and merchantable volume, shorter rotation ages, and better stem form and uniformity. Comparatively little attention has been placed on negative aspects of PCT, such as the incidence and development of root and butt rots, and their impact on fibre yields and wood product values. Results from the Green River study provide evidence that PCT may increase the incidence of butt rot in balsam fir, with incidence proportional to thinning intensity (p < 0.01). We also observed incidence and volume of butt rot to increase with stem diameter (p ≤ 0.05). The experiment suggests that factors such as stand age at time of thinning, and age at the time of harvest are important considerations when it comes to mitigating the impacts of butt rot through forest management.

Estimating coarse root biomass of balsam fir

2007 ◽  
Vol 37 (6) ◽  
pp. 991-998 ◽  
Author(s):  
M.B. Lavigne ◽  
M.J. Krasowski
Keyword(s):  
New Brunswick ◽  
Root Biomass ◽  
Abies Balsamea ◽  
Belowground Biomass ◽  
Root Diameter ◽  
Balsam Fir ◽  
Stand Age ◽  
Coarse Root ◽  
The Relationship ◽  
Diameter Classes

Root systems of 31 balsam fir ( Abies balsamea (L.) Mill.) trees were excavated at five sites in central New Brunswick. Sites ranged from 10 to >80 years in stand age; most had been thinned at least once, and densities ranged from 750 to 44 000 trees·ha–1. The relationship between diameter at breast height and coarse root biomass in the present investigation was similar to one reported for balsam fir in northern New Brunswick but differed from two other published biomass equations. Coarse root biomass per hectare ranged from 3 to 30 Mg·ha–1 among studied sites. Coarse root biomass in the smaller root diameter classes was similar at all sites, but biomass in diameter classes >50 mm increased with stand age. Precommercial thinning added 3 Mg coarse root biomass·ha–1 to the detrital pool. The ratio of coarse root biomass to stem biomass averaged 0.36 (±0.02 SE). These results show that there is more belowground biomass in balsam fir ecosystems than would be expected from the generic ratio of belowground to aboveground biomass often applied to coniferous ecosystems, pointing to a need for using ratios that are more specific.

Interactions among defoliation level, species, and soil richness determine foliage production during and after simulated spruce budworm attack

2020 ◽  
Vol 50 (6) ◽  
pp. 565-580
Author(s):  
Yuanyuan Wu ◽  
David A. MacLean ◽  
Chris Hennigar ◽  
Anthony R. Taylor
Keyword(s):  
Picea Glauca ◽  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
White Spruce ◽  
Shoot Length ◽  
Balsam Fir ◽  
Site Quality ◽  
Number Of Shoots

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.

Patterns of leaf area index during stand development in even-aged balsam fir – red spruce stands

2010 ◽  
Vol 40 (4) ◽  
pp. 629-637 ◽  
Author(s):  
R. Justin DeRose ◽  
Robert S. Seymour
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Abies Balsamea ◽  
Stand Density ◽  
Red Spruce ◽  
Balsam Fir ◽  
Research Network ◽  
Site Quality ◽  
Area Index ◽  
Commercial Thinning

Leaf area index (LAI) strongly controls forest stand production. Silviculturists can easily manage this biologically important variable by quantifying its relationship to more directly manageable stand elements, such as density. Hypothesized patterns of LAI development over relative stand density (RD) in even-aged stands of balsam fir ( Abies balsamea (L.) Mill.) and red spruce ( Picea rubens Sarg.) were examined using 78 plots from the Cooperative Forestry Research Unit’s Commercial Thinning Research Network located in the Acadian forest zone in Maine. Nonlinear regression indicated that LAI was significantly related to RD, site quality, and stand top height. LAI increased nonlinearly with increasing RD holding stand top height constant. At a given RD, LAI peaked at approximately 13 m in stand top height. Site quality positively and linearly influenced LAI, but this was only apparent after crown closure, which in turn was influenced by initial stand density. Five-year trajectories of LAI–RD remeasurement data showed an increase in LAI and RD for all stands that varied by stand top height and site quality. Taken together, RD, stand top height, and site quality are strong predictors of LAI and can be used by silviculturists to manage for LAI.

Soil drainage class, host tree species, and thinning influence host tree resistance to the spruce budworm

2012 ◽  
Vol 42 (10) ◽  
pp. 1771-1783 ◽  
Author(s):  
Alvaro Fuentealba ◽  
Éric Bauce
Keyword(s):  
Abies Balsamea ◽  
Spruce Budworm ◽  
White Spruce ◽  
Host Tree ◽  
Balsam Fir ◽  
Thinning Intensity ◽  
Drainage Class ◽  
Tree Resistance ◽  
Commercial Thinning ◽  
The Impact

Thinning has frequently been recommended for reducing damage caused by spruce budworm ( Choristoneura fumiferana (Clemens)). It is believed that this technique enhances the mechanisms of resistance of trees (antibiosis and tolerance) to this insect. However, various research projects that have focused upon effects of this silvicultural tool on host tree resistance have yielded equivocal results. A better understanding of the effects of this technique on host tree resistance and budworm performance can help us to reduce the impact of this insect while respecting the ecological integrity of the forests. We examined the effects of stand commercial thinning and drainage class on balsam fir ( Abies balsamea (L.) Mill.)), white spruce ( Picea glauca (Moench) Voss), and black spruce ( Picea mariana (Mill.) Britton, Sterns & Poggenb.) resistance to spruce budworm 3 years after thinning. We wanted to determine if this technique could be used as preventive tool against insect defoliators. Field-rearing experiments of spruce budworm were conducted, together with foliar chemical analyses, along a gradient of stand thinning intensity (0% (control), 25% (light), and 40% (heavy)) and drainage class (rapidly drained, class 2; mesic with seepage, class 3; subhygric, class 4; and hydric, class 5). Despite having favoured budworm performance (high pupal mass) and winter survival, heavy thinning increased balsam fir and white spruce tolerance (amount of current-year foliage remaining) to a level that resulted in overall increased host tree resistance to the insect. This response was caused by strong foliage production in reaction to the thinning treatment. Light thinning did not increase host tolerance, except in balsam fir and white spruce that were growing on hydric and subhygric sites, respectively, demonstrating the importance of this variable in determining host tree resistance. These results suggest that heavy thinning may be used as a preventive measure during the low-density phase of budworm populations, since this technique increased foliar production in balsam fir and white spruce, rendering them more resistant to attack by this insect.

Susceptibility of balsam fir to spruce budworm defoliation as affected by thinning

1979 ◽  
Vol 9 (3) ◽  
pp. 428-435 ◽  
Author(s):  
Gregory W. Crook ◽  
Paul E. Vézina ◽  
Yvan Hardy
Keyword(s):  
Forest Type ◽  
Coniferous Forest ◽  
Basal Area ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
Stand Age ◽  
Forest Types ◽  
Mixed Stands ◽  
Number Of Stems

Spruce budworm, Choristoneurafumiferana (Clemens), defoliation of balsam fir, Abiesbalsamea (L.) Mill., was studied in thinned stands of the Lower St. Lawrence region of Quebec. The object of the study was to quantify defoliation levels in treated and control plots in order to determine what effect, if any, thinning had on the susceptibility of balsam fir.Three main forest types were studied: (a) coniferous, (b) mixed, and (c) hardwood with a fir understory. The coniferous forest type was subdivided into three types: (1) pure balsam fir; (2) balsam fir – white spruce, Piceaglauca (Moench) Voss; (3) balsam fir – hardwoods. Defoliation levels were estimated using two current techniques: the Dorais–Hardy (1976) and the Fettes (1950) methods.Susceptibility of balsam fir to spruce budworm defoliation was not affected after thinning in coniferous and hardwood forest types; however, susceptibility was increased in mixed stands when part of the hardwood cover was removed. In any situation, defoliation of fir was found to be more intense with an increase of the basal area of the coniferous species (balsam fir, red spruce, Picearubens Sarg., and white spruce) while an increase of the basal area of hardwoods resulted in lower defoliation levels; likewise, a higher number of stems per hectare brought higher defoliation levels of fir. Defoliation was also found to vary with stand composition; susceptibility of fir in the three main cover types decreased in the following order: (a) coniferous, (b) mixed, (c) hardwood. Stand age was not a factor influencing the susceptibility of balsam fir for the two age classes studied (30 and 50 years).

Influence of stocking, site quality, stand age, low-severity canopy disturbance, and forest composition on sub-boreal aspen mixedwood carbon stocks

2014 ◽  
Vol 44 (3) ◽  
pp. 230-242 ◽  
Author(s):  
Michael Reinikainen ◽  
Anthony W. D’Amato ◽  
John B. Bradford ◽  
Shawn Fraver
Keyword(s):  
Populus Tremuloides ◽  
Abies Balsamea ◽  
Carbon Stocks ◽  
Forest Carbon ◽  
Site Quality ◽  
Forest Composition ◽  
Stand Age ◽  
Forest Tent Caterpillar ◽  
Canopy Disturbance ◽  
Tent Caterpillar

Low-severity canopy disturbance presumably influences forest carbon dynamics during the course of stand development, yet the topic has received relatively little attention. This is surprising because of the frequent occurrence of such events and the potential for both the severity and frequency of disturbances to increase as a result of climate change. We investigated the impacts of low-severity canopy disturbance and average insect defoliation on forest carbon stocks and rates of carbon sequestration in mature aspen mixedwood forests of varying stand age (ranging from 61 to 85 years), overstory composition, stocking level, and site quality. Stocking level and site quality positively affected the average annual aboveground tree carbon increment (CAAI), while stocking level, site quality, and stand age positively affected tree carbon stocks (CTREE) and total ecosystem carbon stocks (CTOTAL). Cumulative canopy disturbance (DIST) was reconstructed using dendroecological methods over a 29-year period. DIST was negatively and significantly related to soil carbon (CSOIL), and it was negatively, albeit marginally, related to CTOTAL. Minima in the annual aboveground carbon increment of trees (CAI) occurred at sites during defoliation of aspen (Populus tremuloides Michx.) by forest tent caterpillar (Malacosoma disstria Hubner), and minima were more extreme at sites dominated by trembling aspen than sites mixed with conifers. At sites defoliated by forest tent caterpillar in the early 2000s, increased sequestration by the softwood component (Abies balsamea (L.) Mill. and Picea glauca (Moench) Voss) compensated for overall decreases in CAI by 17% on average. These results underscore the importance of accounting for low-severity canopy disturbance events when developing regional forest carbon models and argue for the restoration and maintenance of historically important conifer species within aspen mixedwoods to enhance stand-level resilience to disturbance agents and maintain site-level carbon stocks.

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