Testing an individual tree wind damage risk model in a naturally regenerated balsam fir stand: potential impact of thinning on the level of risk

Author(s):  
Marine Duperat ◽  
Barry Gardiner ◽  
Jean-Claude Ruel

Abstract Widely distributed in Quebec, balsam fir (Abies balsamea (L.) Mill.) is highly vulnerable to wind damage. Recently, there has been a trend in forest management to increase the use of partial cuttings in naturally regenerating stands, leaving the remnant trees at increased risk of wind damage. In order to limit wind damage after partial cuttings, it is therefore important to find silvicultural practices that minimize the risk of wind damage in these fir stands. Our main objective was to find balsam fir-specific values of parameters to integrate into the wind risk model ForestGALES, in order to simulate the impact of different types of commercial thinning on wind damage risk, and to determine which practice potentially minimizes the risk in a naturally regenerated stand. An anemometer placed at canopy height and strain gauges attached to the trunks of balsam firs allowed us to measure the wind-induced bending moments experienced by a sample of balsam fir trees. This enabled the calculation of the turning moment coefficients specific to each of the trees in order to compare them with the ForestGALES model predictions and to adapt the model for balsam fir stands. The model was tested first with only tree diameter and height as input variables to calculate the turning moment coefficient, then with the addition of a competition index, and finally with the addition of crown dimensions. Wind climate parameters for prediction of the probability of damage were calculated using the Wind Atlas Analysis and Application Program airflow model. The model with the highest accuracy was then used to simulate two types of thinning and determine the impact on wind damage risk for each tree in the stand. According to the model’s predictions, thinning from below has a reduced risk of wind damage compared with thinning from above.

2012 ◽  
Vol 42 (10) ◽  
pp. 1771-1783 ◽  
Author(s):  
Alvaro Fuentealba ◽  
Éric Bauce

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.


2007 ◽  
Vol 22 (4) ◽  
pp. 285-296 ◽  
Author(s):  
Scott D. Roberts ◽  
Constance A. Harrington ◽  
Karl R. Buermeyer

Abstract Silvicultural treatments designed to enhance stand structural diversity may result in increased wind damage. The ability to avoid conditions that might lead to excessive wind damage would benefit forest managers. We analyzed wind damage following implementation of a variable-density thinning at four sites on the Olympic National Forest in northwest Washington. The prescription created small canopy gaps and retained unthinned patches within a uniformly thinned matrix, thus creating substantial amounts of internal edge. Our objective was to determine whether variable-density thinning resulted in elevated wind damage and whether the damage was spatially related to elements of the treatment, i.e., canopy gaps and uncut patches. Wind damage on the thinned plots averaged slightly more than 8.0 trees/ha. Although precise determinations of residual stem densities were not available, we estimate that total wind damage amounted to 1.3% of total stems remaining following treatment. Approximately 80% of the wind damage was blowdown, the remaining damage being stem breakage, leaning, or bowing. Nearly 54% of the damaged stems were less than 20 cm dbh. The maximum amount of damage observed was 51 trees/ha, but only 3 of 13 thinned plots had wind damage exceeding 7 trees/ha. The overall level of wind damage across all thinned plots after two growing seasons was not statistically greater than on unthinned control plots. Internal edges created by gaps, skid trails, and unthinned patches did not inherently increase wind damage risk; however, where gaps were located in topographically vulnerable positions, greater wind damage did occur. Overall wind damage was not excessive on any of the plots, and after 2 years, all residual stands remained intact and in a manageable condition. Our preliminary results suggest that variable-density thinning that includes creation of small canopy gaps does not necessarily predispose stands to greater risk of wind damage than uniform thinning. However, care must be taken in locating gaps and skid trails away from topographically vulnerable positions.


1990 ◽  
Vol 68 (11) ◽  
pp. 2235-2242 ◽  
Author(s):  
Rhonda L. Millikin

The impact of fenitrothion on the arthropod food of songbirds was measured using white birch (Betula papyrifera Marsh.) and balsam fir (Abies balsamea (L.) Mill.) branch sample and drop trays. Following ground application of fenitrothion at 293 g active ingredient/ha, there was a significant decrease in the biomass of arthropods as determined using branch samples from both tree species, but not until 5 days after the application (29% reduction for balsam fir, 35% for white birch). Samples from drop trays indicated an immediate kill of arthropods not associated with the tree. Most remaining arthropods on treated balsam fir trees were dead. These dead arthropods would not be suitable food for birds that require movement to detect their prey. There was no significant relationship between amount of deposit (treated trees only) and the reduction of arthropods for either tree species.


1998 ◽  
Vol 28 (5) ◽  
pp. 703-710 ◽  
Author(s):  
Erhard John Dobesberger

A stochastic simulation model was developed to derive a damage function for the spruce budworm, Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae), and balsam fir, Abies balsamea (L.) Mill., herbivore interaction at the stand level for open-grown trees. Both aggregated and uniform models of attack pattern by late-instar larvae based on k of the negative binomial were evaluated to determine the impact of larval density and attack pattern on the loss in stemwood volume increment of young, thinned balsam fir stands in Newfoundland. Percentage loss in stemwood increment was a nonlinear, negative exponential function of initial larval density. Implementation of control measures to prevent 50% defoliation that is caused by about 14 larvae/branch tip would result in saving 24% of the annual stemwood increment after 1 year of defoliation and about 32% after 2 years of cumulative defoliation. Aggregation of spruce budworm larvae among trees within a forest stand results in less growth loss compared with a uniform pattern of attack. The nonlinear damage function may suggest tolerance and possibly compensatory growth after herbivory by low population levels of the spruce budworm.


2020 ◽  
Author(s):  
Tom Locatelli ◽  
Sophie Hale ◽  
Bruce Nicoll ◽  
Barry Gardiner

<p>Wind disturbance to forests extends across spatial and temporal scales and encompasses direct and indirect wind effects on the dynamics of forest ecosystems. It is detrimental to the provision of ecosystem services and reduces forest resistance and resilience to future natural disturbances. Historically, in the ecological and land-use scientific communities, forecasting the extent and probability of wind disturbance to forests has represented a serious challenge, with most studies electing to adopt qualitative or statistical approaches. The low degree of portability of statistical assessments of vulnerability to wind has limited their applicability and use, but it is recognised that they have a role in building hypotheses of the processes involved in wind damage that can be subsequently tested under experimental conditions. Results from tree stability experiments have contributed, in the last two decades, to the development of a mechanistic model of wind damage - ForestGALES. This is a process-based wind risk model that was originally created to inform the management of commercial forest plantations in the UK. Built on principles of forest science, physics, and ecology, ForestGALES requires a simple set of inputs and it has now been expanded to cover more than 20 common conifer species from across three continents, and multiple broadleaved species (e.g. Oak, Beech, Birch, and Eucalypts). Two methods of assessing vulnerability to wind damage are available in ForestGALES, one designed for application at stand level, and a novel approach that estimates vulnerability to wind at the individual tree within a stand – the latter allowing for use in complex forest stands, and for the effect of competition between trees in a stand. Until recently, ForestGALES was only available as desktop software and as an online tool as part of forest decision support systems (only for selected countries and species). These formats can be limiting for research and academic projects that aim to model and understanding wind disturbance dynamics across diverse landscapes, and that require a bespoke approach with a high degree of flexibility. To accommodate these broader requirements, ForestGALES has recently been redeveloped and released as a FOSS R package (“<em>fgr</em>”) that is fully customisable and easily integrated in R and modelling workflows and FOSS GIS frameworks. With this poster we present two exemplar studies of assessing wind damage risk to forested landscapes, one for each ForestGALES method (stand- and individual trees level), to showcase the capabilities and flexibility of the model in working with e.g. climate projection data, with other process-based models (e.g. 3PG) within an R modelling framework, and with LiDAR data, at the individual tree level.</p>


1996 ◽  
Vol 72 (4) ◽  
pp. 393-398 ◽  
Author(s):  
Éric Bauce

Field rearing experiments of spruce budworm, Choristoneura fumiferana (Clem.), were conducted in conjunction with foliar chemical analyses, one and two years after a commercial thinning (removal of 25% stand basal area) in a 50-year-old balsam fir, Abies balsamea (L.) Mill., stand. The first year after thinning, spruce budworm larvae reared on the residual trees developed five days faster and removed 43% more foliage than those reared on control trees, but in the second year they developed two days faster and removed 37% more foliage. The increase in larval development rate was related to an increase in foliar soluble sugars while a reduction in foliar monoterpenes caused by the thinning apparently accounted for the greater amount of foliage ingested by the larvae. The first year after thinning, trees were more vulnerable to spruce budworm because there was no increase in foliage production and the trees were more heavily defoliated. However, in the second year trees were less vulnerable to the insect because there was an increase in foliage production that exceeded the increase in defoliation, hence a net gain in foliage. Results from this study showed that commercial thinning could reduce the vulnerability of balsam fir trees to spruce budworm if thinning is conducted two years prior to budworm outbreak, but the same silvicultural procedure could increase the vulnerability to the insect if it is conducted during an outbreak. Key words: spruce budworm, balsam fir, chemistry, thinning, defoliation


2000 ◽  
Vol 76 (4) ◽  
pp. 653-663 ◽  
Author(s):  
Vincent Laflèche ◽  
Jean-Claude Ruel ◽  
Louis Archambault

The effect of careful logging to preserve advance growth was studied in mixedwood stands of the balsam fir (Abies balsamea (L.) Mill.) - yellow birch (Betula alleghaniensis Britton) eco-climatic domain in eastern Quebec, Canada. The study is based on 19 sites harvested five years earlier. In each cutover, 50 sample plots have been established to quantify the abundance of regeneration five years after logging. This cutting method proved to be ineffective in limiting the invasion of competiting species such as mountain maple (Acer spicatum Lam.) and pin cherry (Prunus pensylvanica (L.), which fully occupied the sites with 25 092 and 5619 stems ha−1 respectively. Balsam fir was abundant after five years in the study area with 13 500 stems ha−1 but two thirds of the seedlings were smaller than 30 cm. Soil disturbance was minimal, probably limiting the establishment of yellow birch, which reached a density of 1416 stems ha−1 five years after logging. Height growth projection of regeneration over five years showed that competiting species should still dominate the sites. Commercial species should improve their position but would still account for only 40% of dominant stems. It is therefore unlikely that this regeneration method will be successful in bringing back the initial stand composition in a short period of time. The next stands will probably contain a high proportion of intolerant species with a dominance of paper birch (Betula papyrifera Marsh.) over yellow birch. In the near future, cleaning operations should be conducted to reduce the impact of competing vegetation and make sure that balsam fir will remain in the main canopy.


2004 ◽  
Vol 34 (7) ◽  
pp. 1436-1443 ◽  
Author(s):  
Chantal Lemieux ◽  
Louise Filion

Most mature balsam fir trees (Abies balsamea (L.) Mill.) growing at the top of Mount Mégantic (Quebec) exhibit multiple leaders in the upper crown section, an indication of stressful conditions for tree development in this high-altitude stand. We report here on a detailed dendroecological analysis of windthrown trees showing that multiple stem development was linked to spruce budworm activity during the 1970s. In spite of severe defoliation, damaged trees temporarily restored their vegetative structure by forming reiterated axes. About 9% of all leaders sampled died during a 3-year period (1996-1998), which represents 60% of dead leaders sampled, with tree morbidity and mortality also peaking in 1996. Tree-ring dating of growth anomalies indicated the impact of major snow and (or) ice storms during the 1996 and 1998 winters, two events validated by field observations from the Mount Mégantic conservation area authorities. Biotic (defoliators) and extreme climatic events have a combined influence in the dynamics of high-altitude balsam fir forests.


2016 ◽  
Vol 148 (4) ◽  
pp. 466-475 ◽  
Author(s):  
Richard Berthiaume ◽  
Christian Hébert ◽  
Georges Pelletier ◽  
Conrad Cloutier

AbstractThe balsam twig aphid, Mindarus abietinus Koch (Hemiptera: Aphididae), is one of the most important pests of balsam fir (Abies balsamea (Linnaeus) Miller; Pinaceae) grown as Christmas trees in eastern North America. Aphid feeding on the current-year shoots results in needle distortion and shoots stunting, which reduces the aesthetic value of balsam fir trees and can have substantial economic impact. Syrphidae (Diptera) fly predators attacking this aphid are poorly known. We identified four species attacking the balsam twig aphid. Syrphus torvus Osten Sacken (Diptera: Syrphidae) was the most abundant species followed by Eupeodes lapponicus (Zetterstedt) (Diptera: Syrphidae) and Eupeodes americanus (Wiedemann) (Diptera: Syrphidae). We described the seasonal natural history of the two most abundant syrphids feeding on this aphid and we studied their synchrony with their prey. Syrphid larval density on balsam fir shoots increased rapidly and closely followed density of the balsam twig aphid. We also reported heavy parasitism of syrphid pupae by two Hymenoptera on tree foliage but lower parasitism on pupae in the soil under trees. Several cases of multiple parasitism and hyperparasitism were observed in syrphid pupae under trees. Abundance of predaceous syrphid species was higher in untreated balsam fir plantations compared with treated plantations. More research is needed to understand the role and the impact of these predators on balsam twig aphid population dynamics.


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