A new paleoecological approach to reconstruct long-term history of spruce budworm outbreaks

2002 ◽  
Vol 32 (3) ◽  
pp. 428-438 ◽  
Author(s):  
Isabelle Simard ◽  
Hubert Morin ◽  
Bruno Potelle

A new paleoecological indicator was used for retracing the long-term history of spruce budworm (Choristoneura fumiferana Clem.) outbreaks from forest humus. Macrofossil analyses were performed on 28 forest soil profiles (10–20 cm) collected in four balsam fir (Abies balsamea (L.) Mill.) stands located north of Lake Saint-Jean, Quebec. Direct evidence of the presence of spruce budworm was found. Few pupa fragments were present in the profiles, but the most abundant and well-preserved macrofossils collected were spruce budworm feces. The feces found were associated in part with the three outbreaks that occurred during the last century around 1914, 1952, and 1979. Good correspondence was obtained between the macrofossil results and the known dynamics of two stands, Lib20 and Lib23. However, the method failed to detect specific outbreaks in the other two stands, Lib21 and Lib24. A complementary macrofossil study was conducted on deeper humus profiles (47–70 cm) collected on two islands of Mingan Archipelago. The outbreak history of the last century was retraced, and it was established that spruce budworm was present in the Mingan Archipelago since at least 1520 years BP. The greatest numbers of spruce budworm feces were found in the first 20 cm of the humus profiles corresponding approximately to the 20th century period. Afterward, an important reduction in numbers of feces was observed. This may be attributable to lower levels of spruce budworm populations before the 20th century or the intensification of decomposition with increasing humus depth.

1977 ◽  
Vol 109 (9) ◽  
pp. 1239-1248 ◽  
Author(s):  
O. N. Morris

AbstractBacillus thuringiensis (Dipel® 36B) mixed with a sublethal concentration of acephate (Orthene®) (O, S-dimethyl acetylphosphoramidothioate), an organophosphorous insecticide, was applied at 2.35–14 l./ha to white spruce (Picea glauca) and balsam fir (Abies balsamea) trees infested with spruce budworm, Choristoneura fumiferana (Clem.). The treatment rate was 20 Billion International Units of B. thuringiensis (B.t.) activity with or without 42 g of active ingredient of acephate/ha.The ground deposit of the standard Dipel wettable powder formulation was 12% of emitted volume compared with 21–32% for the Dipel 36B flowable. The viability of B.t. spores was drastically reduced after 1 day of weathering but a high level of biological activity by the spore–crystal complex persisted for up to 20 days post-spray due probably to crystal activity.The addition of about 10% of the recommended operational rate of acephate to the B.t. suspension increased larval mortality by 34% when applied at 4.7 l./ha. Reductions in budworm populations were 97–99% in B.t. + acephate plots and 86–90% in B.t. alone plots.Plots with moderate budworm densities of up to 27 larvae/100 buds on white spruce and 36/100 on balsam fir were satisfactorily protected from excessive defoliation in the year of spray by B.t. with or without acephate. Plots with higher population densities were not satisfactorily protected based on the branch sample examination but aerial color photographs indicated good protection to the top third of the trees. Population declines were greater and defoliation and oviposition were lower in the treated plots than in the untreated checks 1 year later without further treatment. Two years later the larval population densities in all plots were low but the density was twice as high in the untreated check as in the treated plots, indicating long term suppression by the treatments. Defoliation was negligible in all plots.The treatments had no deleterious effect on spruce budworm parasitism. The data indicate that the integrated approach using Bacillus thuringiensis – chemical pesticide combinations is a viable alternative to the use of chemical pesticides alone in spruce budworm control. Large scale testing is now warranted.


1983 ◽  
Vol 59 (6) ◽  
pp. 294-297 ◽  
Author(s):  
J. R. Blais

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.


1983 ◽  
Vol 13 (4) ◽  
pp. 539-547 ◽  
Author(s):  
J. R. Blais

The history of spruce budworm (Choristoneurafumiferana (Clem.)) outbreaks for the past 200 to 300 years, for nine regions in eastern Canada, indicates that outbreaks have occurred more frequently in the 20th century than previously. Regionally, 21 outbreaks took place in the past 80 years compared with 9 in the preceding 100 years. Earlier infestations were restricted to specific regions, but in the 20th century they have coalesced and increased in size, the outbreaks of 1910, 1940, and 1970 having covered 10, 25, and 55 million ha respectively. Reasons for the increase in frequency, extent, and severity of outbreaks appear mostly attributable to changes caused by man, in the forest ecosystem. Clear-cutting of pulpwood stands, fire protection, and use of pesticides against budworm favor fir–spruce stands, rendering the forest more prone to budworm attack. The manner and degree to which each of these practices has altered forest composition is discussed. In the future, most of these practices are expected to continue and their effects could intensify, especially in regions of recent application. Other practices, including large-scale planting of white spruce, could further increase the susceptibility of forest stands. Forest management, aimed at reducing the occurrence of extensive fir–spruce stands, has been advocated as a long-term solution to the budworm problem. The implementation of this measure at a time when man's actions result in the proliferation of fir presents a most serious challenge to forest managers.


1983 ◽  
Vol 115 (4) ◽  
pp. 431-434
Author(s):  
O. N. Morris ◽  
A. Moore

AbstractLarval biomass of the spruce bud worm, Choristoneura fumiferana (Clem.), in balsam fir, Abies balsamea L., stands was significantly reduced following aerial applications of commercial Bacillus thuringiensis (B.t.) (Thuricide 16B®, 24B and 32BX and Dipel 85®). Treatment with Dipel vehicle (Dipel 88® without B.t.) did not affect larval biomass. Biomass reduction following the Thuricide treatment was directly related to feeding activity. These findings support published observations on the long-term effect of B.t. on budworm populations.


2012 ◽  
Vol 42 (7) ◽  
pp. 1264-1276 ◽  
Author(s):  
Yan Boulanger ◽  
Dominique Arseneault ◽  
Hubert Morin ◽  
Yves Jardon ◽  
Philip Bertrand ◽  
...  

It is argued that spruce budworm ( Choristoneura fumiferana (Clemens)) (SBW) outbreaks have tended to be more frequent, severe, and spatially synchronized since the beginning of the 20th century. However, few studies have assessed the long-term (>200 years) variations in SBW outbreak dynamics. We reconstructed the SBW outbreak history at the northern limit of the temperate forest in southern Quebec using dendrochronological material from old buildings and five old-growth stands. Our regional tree-ring chronology (1551–1995) represents one of the longest and most replicated insect outbreak reconstructions in North America. Nine potential outbreaks were identified (1976–1991, 1946–1959, 1915–1929, 1872–1903, 1807–1817, 1754–1765, 1706–1717, 1664–1670, and 1630–1638) with three additional uncertain outbreaks (1647–1661, 1606–1619, and 1564–1578). Results suggested that southern Quebec has experienced frequent and synchronized outbreaks throughout the last 400 years. Although outbreak frequency was higher during the 20th century (approximately 30 years) as compared with the 1660–1850 period (approximately 50 years), similar or even higher outbreak frequency might have occurred prior to 1660 (approximately 28 years). We did not find any evidence that the recent outbreak dynamics in southern Quebec is outside its historical range of the last 400 years. Previous studies based on living trees may have underestimated outbreak frequency and synchrony prior to 1900.


1961 ◽  
Vol 93 (2) ◽  
pp. 118-123 ◽  
Author(s):  
J. G. Pilon ◽  
J. R. Blais

Nearly all forest regions in the Province of Quebec where balsam fir (Abies balsamea (L.) Mill.) is an important tree component have been subjected to severe defoliation by the spruce budworm, Choristoneura fumiferana (Clem.), during the past 20 years. These outbreaks have followed an easterly direction beginning near the Ontario-Quebec border in 1939 and ending in the Gaspé Peninsula in 1958.


1986 ◽  
Vol 62 (2) ◽  
pp. 96-100 ◽  
Author(s):  
D. J. McRae

Recent spruce budworm (Choristoneura fumiferana [Clem.]) infestations have resulted in widespread areas of balsam fir (Abies balsamea [L.] Mill.) mortality in Ontario, and there is growing interest in reestablishing these areas quickly as productive forests. One technique being used is prescribed fire after a salvage and bulldozer tramping operation. A 445-ha prescribed burn was carried out under moderate fire danger conditions in northern Ontario. The site, which was covered by balsam fir fuel that had been killed by spruce budworm, was tramped to improve fire spread. Weather, fuel consumption, and fire effects are reported. The burn effectively reduced heavy surface fuel loadings and consequently planting on the site was easier. Key words: Prescribed burning, fire, spruce budworm. Choristoneura fumiferana, balsam fir, Abies balsamea, fuel consumption, site preparation, tramping, stand conversion.


1996 ◽  
Vol 128 (6) ◽  
pp. 1109-1113 ◽  
Author(s):  
Harald Piene

AbstractDetailed estimates of defoliation caused by spruce budworm [Choristoneura fumiferana (Clem.)] over the crown length of young balsam fir [Abies balsamea (L.) Mill.] were made throughout a spruce budworm outbreak from 1976 to 1984 in the Cape Breton Highlands, Nova Scotia. The results show no clear tendency for a particular level of the crown to be damaged more heavily than any other. Thus, there is no reason to continue the common practice of taking samples from the mid-crown level on the assumption that they represent an ‘average’ level of defoliation either for high or low populations. Sampling from the bottom of the crown should provide a more convenient and cost-effective approach for estimating defoliation.


1961 ◽  
Vol 93 (5) ◽  
pp. 360-379 ◽  
Author(s):  
F. E. Webb ◽  
J. R. Blais ◽  
R. W. Nash

The spruce budworm (Choristoneura fumiferana (Clem.)) is a forest pest in all Canadian Provinces and Territories, and in the northeastern, midwest, and northwestern Unired States. It is by iar the most destructive insect affeiting the extensive balsam fir-spruce forest types in Ontario, Quebec, the Maritime Provinces, and Maine. Outbreaks of varying extent have been reported from these regions almost every year for the past half-century (deGryse, 1947). Periods in which outbreaks were particularly severe and widespread occurred from about 1909 to 1920 and in the 1940's and 1950's. In both periods, outbreaks showed a tendency to shift from west to east, intensifying first in parts of northern Ontario and Quebec and dying out in the Atlantic region south of the St. Lawrence River.


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