Effectiveness of spruce budworm spraying in New Brunswick in protecting the spruce component of spruce–fir stands

1984 ◽  
Vol 14 (2) ◽  
pp. 163-176 ◽  
Author(s):  
David A. MacLean ◽  
A. Wayne Kline ◽  
Daniel R. Lavigne
Keyword(s):  
New Brunswick ◽  
Tree Mortality ◽  
Black Spruce ◽  
Minor Component ◽  
Spruce Budworm ◽  
Total Sample ◽  
Site Characteristics ◽  
Spruce Stands ◽  
Spruce Mortality ◽  
A Minor

Tree mortality and defoliation were examined in 45 spruce (Picea sp.) stands protected against damage by spruce budworm (Choristoneurafumiferana (Clem.)) and in 27 unprotected spruce stands in New Brunswick, and were related to tree, stand, and site characteristics. The "protected" and "unprotected" classes of stands were defined on the basis of any spraying in the last 5 years (1978–1982), but we also estimated the spray and budworm hazard history from 1973 to 1982 for each stand. Based on this total sample of about 17 000 trees, there was little difference in mortality levels of spruce or combined spruce–fir (Abiesbalsamea (L.) Mill.) between protected and unprotected stands. Spruce mortality was relatively low in both protected and unprotected stands, averaging about 13 and 20% of the total volume, respectively. Fir mortality was higher in unprotected than in protected stands, although fir formed only a minor component of most of the sampled stands. Both average mortality and range were similar among the four spruce types present in New Brunswick: black spruce (Piceamariana (Mill.) B.S.P.), red spruce (Picearubens Sarg.), hybrid red–black spruce, and white spruce (Piceaglauca (Moench) Voss). In examining the relation of tree mortality to stand and site characteristics, the strongest correlations were found between dead spruce–fir volume (cubic metres per hectare) and total stand volume (r = 0.85), and between dead fir volume and total fir volume (r = 0.75). No apparent relationships were observed between mortality levels and various indices of protection and budworm hazard. It should be emphasized in presenting these results that the spray program in New Brunswick has historically been designed to protect fir, so that any protection afforded to spruce would be entirely an incidental benefit from attention to the fir problem. Although our results do not reflect a failure of a clearly defined effort to protect spruce, we do recommend that further protection efforts for spruce in New Brunswick be reevaluated.

Causality in mortality patterns of spruce trees during a spruce budworm outbreak

1989 ◽  
Vol 19 (5) ◽  
pp. 632-638 ◽  
Author(s):  
Akira Osawa
Keyword(s):  
Species Complex ◽  
Close Relationships ◽  
Tree Mortality ◽  
Black Spruce ◽  
Basal Area ◽  
Spruce Budworm ◽  
Red Spruce ◽  
Hybrid Index ◽  
The Mean ◽  
Spruce Mortality

Patterns of tree mortality in the species complex of red spruce (Picearubens Sarg.), black spruce (Piceamariana (Mill.) B.S.P.) and their possible hybrids that developed during a spruce budworm (Choristoneurafumiferana (Clem.)) outbreak in Maine, U.S.A., were analyzed in relation to five hypotheses of their causal mechanisms. The observed patterns of spruce mortality were primarily a result of the phenotypic variation among the spruces. Close relationships among the mean hybrid index of spruce trees in a plot and such stand variables as balsam fir (Abiesbalsamea (L.) Mill.) basal area and drainage index are likely to have created coincidental correlations between tree mortality and those variables that do not necessarily reflect causality.

scholarly journals Success Factors for Experimental Partial Harvesting in Unmanaged Boreal Forest: 10-Year Stand Yield Results

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1199
Author(s):  
Louiza Moussaoui ◽  
Alain Leduc ◽  
Miguel Montoro Girona ◽  
Annie Claude Bélisle ◽  
Benoit Lafleur ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Tree Mortality ◽  
Stand Structure ◽  
Black Spruce ◽  
Organic Layer ◽  
Stand Development ◽  
Partial Harvesting ◽  
Site Characteristics ◽  
Spruce Stands ◽  
Stand Yield

Over the past two decades, partial harvesting has been increasingly used in boreal forests as an alternative to clearcutting to promote irregular stand structures and maintain a balance between biodiversity preservation and continued timber production. However, relatively little is still known about the silvicultural potential of partial harvesting in Canada’s boreal forest, especially in areas prone to organic matter accumulation (paludification), and most prior research has focused on biodiversity responses. In this study, we assess the effects of partial harvesting on stand development (recruitment, growth, and mortality) ten years after harvesting in previously unmanaged black spruce stands and quantify its effectiveness in reducing the impacts on ecosystem structures. Our analyses revealed that pre-harvest stand structure and site characteristics, especially initial basal area, sapling density, tree diameter, and organic layer thickness (OLT) were major factors involved in stand development ten years following these partial harvesting treatments. Depending on pre-harvest structure and site characteristics, partial harvesting can result in either an increase in post-harvest tree recruitment and growth or a loss of stand volume because of standing tree mortality. To increase the chances of partial harvesting success in ensuring an increase in decennial stand yield after harvest in black spruce forest stands, sites prone to paludification (i.e., where OLT >17 cm) should be left unharvested. This study illustrates the importance of taking into account pre-existing structure and site characteristics in the selection of management strategies to maximize the potential of partial harvesting to achieve sustainable forest management in black spruce stands.

scholarly journals Sample Sizes Required To Estimate Defoliation of Spruce and Balsam Fir Caused by Spruce Budworm Accurately

1998 ◽  
Vol 15 (3) ◽  
pp. 135-140 ◽  
Author(s):  
David A. MacLean ◽  
Wayne E. MacKinnon
Keyword(s):  
Black Spruce ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Sample Sizes ◽  
Preliminary Assessment ◽  
Travel Costs ◽  
Host Trees ◽  
Sampling Protocols ◽  
Spruce Stands ◽  
Number Of Branches

Abstract Data from the assessment of current defoliation levels on 172,000 individual shoots from 6890 midcrown branches sampled from balsam fir and spruce stands were used to define sampling protocols for assessing defoliation caused by spruce budworm. The method was based on sampling one midcrown branch from each of x host trees per stand, and assessing defoliation of y individual shoots per branch. Both the number of shoots per branch and the number of branches required per stand varied with host species (balsam fir, white spruce, or red-black spruce) and with average defoliation level. Sample sizes required to estimate mean defoliation with 90% confidence that the confidence interval is ±10% ranged from 7 to 24 branches per stand and from 17 to 58 shoots per branch, with the largest samples required at moderate (31-70%) defoliation levels. Estimated costs of shoot and branch sampling and processing ranged from $40-110/stand, based on a 90% confidence level salary rate of $12(Can.)/hr, and excluding travel costs. Results can be applied using a preliminary assessment to determine the general defoliation level, which along with species, determines the required sample size. North. J. Appl. For. 15(3):135-140.

scholarly journals SPRUCE BUDWORM DAMAGE TO BALSAM FIR IN IMMATURE STANDS, QUEBEC

1964 ◽  
Vol 40 (3) ◽  
pp. 372-383 ◽  
Author(s):  
R. J. Hatcher
Keyword(s):  
Minor Component ◽  
Basal Area ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Hardwood Forest ◽  
Cover Type ◽  
Area Reduction ◽  
A Minor ◽  
Very High ◽  
Diameter Classes

A study was made of the effect of the 1945-1957 spruce budworm infestation on 1,800 acres of spruce-fir and spruce-fir-hardwood forest logged for pulpwood about 15 years prior to the infestation.The number of fir trees was reduced 64 per cent between 1951 and 1961 in the main cover type representing 69 per cent of the forest; fir was reduced from a major stand component of 45 per cent by volume to a minor component of 11 per cent. The basal area reduction of fir varied directly with the fir basal area at the time of the outbreak. Losses were very high in stands containing over 20 sq. ft. of fir per acre.These young stands did not exhibit the degree of resistance to damage often observed in young stands elsewhere. But in spite of heavy losses through all diameter classes, the amount of spruce and fir regeneration that survived to 1961 is believed adequate to produce a pulpwood crop within 60 years.

Predicting Tree Mortality Induced by Spruce Budworm: A Discussion

1983 ◽  
Vol 59 (6) ◽  
pp. 294-297 ◽  
Author(s):  
J. R. Blais
Keyword(s):  
Regional Differences ◽  
Tree Mortality ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Reliable Prediction ◽  
Spruce Stands ◽  
Term Management ◽  
Forest Managers

Forest managers have expressed the need for guidelines that would predict, up to 5 years, the annual spruce budworm damage on a stand basis. Reasons why reliable prediction is generally not possible are discussed. It is suggested that long-term management programs, that would take into consideration periodic losses resulting from recurring budworm outbreaks and that would be based on regional differences in the vulnerability of fir-spruce stands, should be implemented. Key words: Spruce budworm, Choristoneura fumiferana; forest management; tree mortality; defoliation; stand vulnerability, balsam fir, Abies balsamea.

scholarly journals Vulnerability of Conifer Regeneration to Spruce Budworm Outbreaks in the Eastern Canadian Boreal Forest

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 850 ◽  
Author(s):  
Janie Lavoie ◽  
Miguel Montoro Girona ◽  
Hubert Morin
Keyword(s):  
Boreal Forests ◽  
Black Spruce ◽  
Choristoneura Fumiferana ◽  
Management Strategies ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Insect Outbreaks ◽  
Spruce Stands ◽  
Canadian Boreal Forest

Spruce budworm (Choristoneura fumiferana) is the main defoliator of conifer trees in North American boreal forests, affecting extensive areas and causing marked losses of timber supplies. In 2017, spruce budworm affected more than 7 million ha of Eastern Canadian forest. Defoliation was particularly severe for black spruce (Picea mariana (Mill.) B.S.P.), one of the most important commercial trees in Canada. During the last decades, intensive forest exploitation practices have created vast stands of young balsam fir (Abies balsamea (L.) Mill.) and black spruce. Most research focused on the impacts of spruce budworm has been on mature stands; its effects on regeneration, however, have been neglected. This study evaluates the impacts of spruce budworm on the defoliation of conifer seedlings (black spruce and balsam fir) in clearcuts. We measured the cumulative and annual defoliation of seedlings within six clearcut black spruce stands in Quebec (Canada) that had experienced severe levels of defoliation due to spruce budworm. For all sampled seedlings, we recorded tree species, height class, and distance to the residual forest. Seedling height and species strongly influenced defoliation level. Small seedlings were less affected by spruce budworm activity. As well, cumulative defoliation for balsam fir was double that of black spruce (21% and 9%, respectively). Distance to residual stands had no significant effect on seedling defoliation. As insect outbreaks in boreal forests are expected to become more severe and frequent in the near future, our results are important for adapting forest management strategies to insect outbreaks in a context of climate change.

Accuracy of aerial sketch-mapping estimates of spruce budworm defoliation in New Brunswick

1996 ◽  
Vol 26 (12) ◽  
pp. 2099-2108 ◽  
Author(s):  
David A. MacLean ◽  
Wayne E. MacKinnon
Keyword(s):  
Decision Support ◽  
New Brunswick ◽  
Decision Support Systems ◽  
Tree Mortality ◽  
Support Systems ◽  
Spruce Budworm ◽  
Weather Conditions ◽  
Balsam Fir ◽  
Small Aircraft

The accuracy of aerial sketch-mapping estimates of spruce budworm (Choristoneurafumiferana (Clem.)) defoliation was evaluated from 1984 to 1993 in 222–325 sample plots in spruce (Picea sp.)–balsam fir (Abiesbalsamea (L.) Mill.) stands in New Brunswick. Operational aerial defoliation estimates were used, wherein all productive forest in known budworm infestation zones was surveyed each year from small aircraft with flight lines 2–5 km apart, and rated in classes of nil (0–10%), light (11–30%), moderate (31–70%), and severe (71–100%). Aerial defoliation estimates were compared with ground-based binocular estimates of current defoliation for an average of 10 trees/plot (range 5–20). Overall, 56% of plots were correctly rated by aerial sketch mapping in four classes (nil, light, moderate, and severe), with 37% of the plots underestimated and 7% overestimated. The predominant error (26% of plots) was rating defoliation as nil (0–10%) from the air when it was actually light (11–30%). This error was deemed not important in terms of predicting tree response, since data from the literature indicated that defoliation less than 30% did not cause tree mortality, although if continued, it would reduce growth. Using three defoliation classes (by combining nil and light, 0–30%), 82% of the plots were correctly classified by aerial sketch mapping. The probability of correct aerial classification of defoliation was significantly affected by defoliation class, weather conditions prior to and during observation flights, and the defoliation class × weather interaction. It was concluded that aerial sketch mapping of spruce budworm defoliation is a viable technique that can be used for both surveys and decision support systems that estimate forest response to budworm outbreaks and management activities.

Rate and causes of decline of mature and overmature balsam fir and spruce stands in New Brunswick, Canada

2005 ◽  
Vol 35 (10) ◽  
pp. 2479-2490 ◽  
Author(s):  
Sarah Lesley Taylor ◽  
David A MacLean
Keyword(s):  
New Brunswick ◽  
Tree Mortality ◽  
Abies Balsamea ◽  
Species Group ◽  
Balsam Fir ◽  
Insect Outbreak ◽  
Permanent Sample Plots ◽  
Dead Trees ◽  
Spruce Stands ◽  
Species Groups

Data from 585 balsam fir (Abies balsamea (L.) Mill.) and spruce (Picea spp.) permanent sample plots (PSPs) >50 years old in New Brunswick, Canada, measured between 1987 and 1998, were used to quantify the timing, magnitude, and causes of decline in stand growth, measured as negative net volume increment. Plots were subdivided into classes based on species group, ecoregion, and volume-development pattern (decreasing, fluctuating, stable, or increasing volume with time). Decline began at an earlier age in balsam fir – spruce (BFSP) PSPs (~70 years old) than in spruce – balsam fir (SPBF) PSPs (~120 years). One-third of plots (29%) fell into the decreasing volume-development category. Variation in the proportion of decreasing plots occurred among ecoregions (range 0%–60%) and, to a lesser extent, among species groups (26%–33%). Decreasing BFSP plots exhibited double the rate of volume loss of their SPBF counterparts (–7.4 and –3.9 m3·ha–1·year–1, respectively). Decline was caused by an increased rate of mortality, which was highest in the decreasing volume-development classes (7.5 m3·ha–1·year–1) and lowest in the increasing volume-development classes (1.4 m3·ha–1·year–1). Growth of surviving trees remained relatively stable (2.5–4.2 m3·ha–1·year–1) among volume-development classes. Blowdown was the biggest cause of tree mortality, accounting for approximately 50% of dead trees in BFSP and SPBF plots. The rate of mortality was influenced by ecoregion, species, and the combined effect of previous insect-outbreak and wind disturbances.

Dynamics and morphology of giant circular patterns of low tree density in black spruce stands in northern Quebec

2001 ◽  
Vol 79 (4) ◽  
pp. 420-428 ◽  
Author(s):  
Jean-François Giroux ◽  
Yves Bergeron ◽  
Jean J Veillette
Keyword(s):  
Surface Water ◽  
Picea Mariana ◽  
Black Spruce ◽  
Mineral Soil ◽  
Tree Density ◽  
Surface Elevation ◽  
Organic Layer ◽  
Spruce Stands ◽  
Spruce Mortality ◽  
Soil Measurements

Giant circular patterns of low tree density in black spruce (Picea mariana) stands were investigated in the Abitibi region of Quebec. We used dendrochronological techniques to test the hypotheses that ring patterns of low tree density are caused either by radial changes in spruce mortality or productivity. Seven circles were sampled. We found no gradient in the age of spruce along circle radii suggesting that rings of low tree density do not expand radially, that is, they are not spatially dynamic entities. The results indicate, however, that spruce trees were less dense and productive within the rings due to excessive moisture in the soil. Measurements of surface elevation, thickness of the organic layer and elevation of the mineral substrate across the circles revealed that a depression in the mineral soil beneath the rings traps the surface water and this area of poor drainage seems to prevent the establishment of black spruce within the rings. The origin of the ring-shaped depressions was attributed to geological or geomorphological causes.Key words: black spruce, Picea mariana, mortality, productivity, rings, geomorphology.

Densities of breeding birds and changes in vegetation in an Alaskan boreal forest following a massive disturbance by spruce beetles

2001 ◽  
Vol 79 (9) ◽  
pp. 1678-1690 ◽  
Author(s):  
Steven M Matsuoka ◽  
Colleen M Handel ◽  
Daniel R Ruthrauff
Keyword(s):  
Picea Glauca ◽  
Tree Mortality ◽  
Black Spruce ◽  
Bird Species ◽  
Tamiasciurus Hudsonicus ◽  
Forest Stands ◽  
Dendroctonus Rufipennis ◽  
Individual Bird ◽  
Large Outbreak ◽  
Spruce Mortality

We examined bird and plant communities among forest stands with different levels of spruce mortality following a large outbreak of spruce beetles (Dendroctonus rufipennis (Kirby)) in the Copper River Basin, Alaska. Spruce beetles avoided stands with black spruce (Picea mariana) and selectively killed larger diameter white spruce (Picea glauca), thereby altering forest structure and increasing the dominance of black spruce in the region. Alders (Alnus sp.) and crowberry (Empetrum nigrum) were more abundant in areas with heavy spruce mortality, possibly a response to the death of overstory spruce. Grasses and herbaceous plants did not proliferate as has been recorded following outbreaks in more coastal Alaskan forests. Two species closely tied to coniferous habitats, the tree-nesting Ruby-crowned Kinglet (Regulus calendula) and the red squirrel (Tamiasciurus hudsonicus), a major nest predator, were less abundant in forest stands with high spruce mortality than in low-mortality stands. Understory-nesting birds as a group were more abundant in forest stands with high levels of spruce mortality, although the response of individual bird species to tree mortality was variable. Birds breeding in stands with high spruce mortality likely benefited reproductively from lower squirrel densities and a greater abundance of shrubs to conceal nests from predators.

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