Episodic recruitment of the seedling banks in balsam fir and white spruce

2012 ◽  
Vol 99 (12) ◽  
pp. 1942-1950 ◽  
Author(s):  
Sergio Rossi ◽  
Hubert Morin ◽  
François Gionest ◽  
Danielle Laprise
Keyword(s):  
White Spruce ◽  
Balsam Fir ◽  
Episodic Recruitment

Root rot damage in naturally regenerated stands of spruce and balsam fir in Ontario

1989 ◽  
Vol 19 (3) ◽  
pp. 295-308 ◽  
Author(s):  
R. D. Whitney
Keyword(s):  
Root Rot ◽  
Black Spruce ◽  
Basal Area ◽  
Ground Level ◽  
White Spruce ◽  
Balsam Fir ◽  
Tree Age ◽  
Stand Age ◽  
Root Decay ◽  
Forest Region

In an 11-year study in northern Ontario, root rot damage was heaviest in balsam fir, intermediate in black spruce, and least in white spruce. As a result of root rot, 16, 11, and 6%, respectively, of dominant or codominant trees of the three species were killed or experienced premature windfall. Butt rot, which resulted from the upward extension of root rot into the boles of living trees, led to a scaled cull of 17, 12, and 10%, respectively, of gross merchantable volume of the remaining living trees in the three species. The total volume of wood lost to rot was, therefore, 33, 23, and 16%, respectively. Of 1108 living dominant and codominant balsam fir, 1243 black spruce, and 501 white spruce in 165 stands, 87, 68, and 63%, respectively, exhibited some degree of advanced root decay. Losses resulting from root rot increased with tree age. Significant amounts of root decay and stain (>30% of root volume) first occurred at 60 years of age in balsam fir and 80 years in black spruce and white spruce. For the three species together, the proportion of trees that were dead and windfallen as a result of root rot increased from an average of 3% at 41–50 years to 13% at 71–80 years and 26% at 101–110 years. The root rot index, based on the number of dead and windfallen trees and estimated loss of merchantable volume, also increased, from an average of 17 at 41–50 years to 40 at 71–80 years and 53 at 101–110 years. Death and windfall of balsam fir and black spruce were more common in northwestern Ontario than in northeastern Ontario. Damage to balsam fir was greater in the Great Lakes–St. Lawrence Forest region than in the Boreal Forest region. In all three tree species, the degree of root rot (decay and stain) was highly correlated with the number of dead and windfallen trees, stand age, and root decay at ground level (as a percentage of basal area) for a 10-tree sample.

LONG TERM STUDY OF THE EFFECTIVENESS OF AERIAL APPLICATION OF BACILLUS THURINGIENSIS – ACEPHATE COMBINATIONS AGAINST THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1977 ◽  
Vol 109 (9) ◽  
pp. 1239-1248 ◽  
Author(s):  
O. N. Morris
Keyword(s):  
Bacillus Thuringiensis ◽  
Choristoneura Fumiferana ◽  
Larval Mortality ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
Population Densities ◽  
Long Term Study

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.

scholarly journals Splitting in Fire-Killed Trees in the Boreal Forest of Alberta

2003 ◽  
Vol 20 (4) ◽  
pp. 167-174
Author(s):  
Nobutaka Nakamura ◽  
Paul M. Woodard ◽  
Lars Bach
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Black Spruce ◽  
Lodgepole Pine ◽  
White Spruce ◽  
Balsam Fir ◽  
Crown Fire ◽  
In Fire ◽  
Solar Angle

Abstract Tree boles in the boreal forests of Alberta, Canada will split once killed by a stand-replacing crown fire. A total of 1,485 fire-killed trees were sampled, 1 yr after burning, in 23 plots in 14 widely separated stands within a 370,000 ha fire. Sampling occurred in the Upper and Lower Foothills natural subregions. The frequency of splitting varied by species but averaged 41% for all species. The order in the frequency of splitting was balsam fir, black spruce, white spruce and lodgepole pine. The type of splitting (straight, spiral, or multiple) varied by species, as did the position of the split on the tree bole. Aspect or solar angle was not statistically related to the type or occurrence of splitting.

The Sensitivity of Young White Spruce to Spruce Budworm Defoliation

1991 ◽  
Vol 8 (4) ◽  
pp. 168-171 ◽  
Author(s):  
Harald Piene
Keyword(s):  
Volume Growth ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
First Year ◽  
Average Volume ◽  
Shoot Production ◽  
Prolific Shoot

Abstract Relationships between defoliation and volume growth were determined for 68 young white spruce trees in a 20-year-old plantation defoliated over a 2-year period by the spruce budworm. In the first year of defoliation, intensities ranging from 7 to 89% of the current foliage did not influence volume growth significantly. Two consecutive years of defoliation, averaging over the 2-year period from 0-33, 34-66, and 67-100% of the current foliage, reduced average volume growth by about 6, 11, and 27%, respectively. White spruce is much less sensitive to defoliation than balsam fir. This is partly due to white spruce's ability to compensate for even moderate defoliation intensities by a prolific shoot production. North. J. Appl. For. 8(4):168-171.

OPTIMAL SAMPLE SIZE FOR THE ESTIMATION OF SPRUCE BUDWORM (LEPIDOPTERA: TORTRICIDAE) POPULATIONS ON BALSAM FIR AND WHITE SPRUCE

1983 ◽  
Vol 115 (12) ◽  
pp. 1621-1626 ◽  
Author(s):  
Jacques Régnière ◽  
C. J. Sanders
Keyword(s):  
Population Density ◽  
Sample Size ◽  
Host Species ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
Larval Population ◽  
Optimal Sample Size ◽  
Optimal Sample

AbstractAn equation is presented for the determination of sample sizes needed to estimate with a given precision the larval population density of spruce budworm on balsam fir and white spruce branch tips in Ontario. This equation is primarily applicable to low densities, but is valid to a density of 50 larvae/branch tip. The distribution of budworm larvae at densities below 0.1/branch tip is nearly random, and is aggregated at higher densities. Their distribution is the same on the two host species.

Histoire récente des épidémies de la Tordeuse des bourgeons de l'épinette au nord du lac Saint-Jean (Québec): une analyse dendrochronologique

1990 ◽  
Vol 20 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Hubert Morin ◽  
Danielle Laprise
Keyword(s):  
Population Dynamics ◽  
White Spruce ◽  
Balsam Fir ◽  
Growth Rings ◽  
The Past ◽  
The North ◽  
Host Trees ◽  
Dendrochronological Analysis ◽  
Wildlife Reserve ◽  
Ecological Disturbances

The chronology of spruce budworm (Choristoneurafumiferana (Clem.)) oubreaks for the past 200 years has been reconstructed by dendrochronological analysis of balsam fir (Abiesbalsamea (L.) Mill.) and white spruce (Piceaglauca (Moench) Voss) samples from virgin forests, unaffected by insecticide spraying programs and recently protected against fires in the north and northwest of Lac Saint-Jean. Outbreaks began around 1974, 1944, 1909, and possibly, 1832. They are closely linked with those described in the Laurentide wildlife reserve. The frequency, duration and severity of growth rings suppression associated with outbreaks are similar to those registered during outbreaks in the southern forests, except for the 1974 outbreak, which was shorter and less severe. Other outbreaks registered in southern regions, where the proportion of balsam fir is higher, have reached this region where balsam fir populations are marginal. These results underline the importance of these ecological disturbances in the population dynamics of the host trees of the region.

Résistance comparée de l'épinette blanche et du sapin baumier au renversement

2002 ◽  
Vol 32 (4) ◽  
pp. 642-652 ◽  
Author(s):  
S Meunier ◽  
J -C Ruel ◽  
G Laflamme ◽  
A Achim
Keyword(s):  
Tree Species ◽  
Picea Glauca ◽  
Abies Balsamea ◽  
White Spruce ◽  
Diameter Ratio ◽  
Balsam Fir ◽  
Species Vulnerability ◽  
Mesic Site ◽  
Linear Regressions ◽  
Tree Characteristics

Information on eastern Canadian tree species vulnerability to windthrow is scarce. Some statements on relative species vulnerability have been made but they rely on empirical observations, which are often difficult to generalize. In this context, a study was conducted to compare the overturning resistance of balsam fir (Abies balsamea (L.) Mill.) and white spruce (Picea glauca (Moench) Voss) on a mesic site. To establish which tree characteristics would best explain the critical turning moment, simple linear regressions were calculated using tree dendrometric data. The best regressions were obtained with stem weight. With this variable, resistance to overturning did not differ between the two species. Only regressions involving total height showed a significantly greater resistance for white spruce. This difference can be explained by a difference between the species in height–diameter relationships. For a similar height, spruce has a greater diameter, involving a higher stem weight and thus a greater resistance. Decay did not play a major role in our experiment as trees with external defects were excluded. Our results suggest that to minimize losses from windthrow, silvi cultural treatments on mesic sites should try to increase the proportion of trees of either species with the lowest height/diameter ratio.

Tree growth response to climate change at the deciduous–boreal forest ecotone, Ontario, Canada

2005 ◽  
Vol 35 (11) ◽  
pp. 2709-2718 ◽  
Author(s):  
D Goldblum ◽  
L S Rigg
Keyword(s):  
Climate Change ◽  
Boreal Forest ◽  
Sugar Maple ◽  
White Spruce ◽  
Balsam Fir ◽  
Northern Limit ◽  
Monthly Temperature ◽  
Temperature And Precipitation ◽  
The Future ◽  
Forest Ecotone

We consider the implications of climate change on the future of the three dominant forest species, sugar maple (Acer saccharum Marsh.), white spruce (Picea glauca (Moench) Voss), and balsam fir (Abies balsamea (L.) Mill.), at the deciduous–boreal forest ecotone, Ontario, Canada. Our analysis is based on individual species responses to past monthly temperature and precipitation conditions in light of modeled (general circulation model) monthly temperature and precipitation conditions in the study area for the 2080s. We then consider the tree species sensitivity to past climate with predicted conditions for the 2080 period. Sugar maple, located at its northern limit in the study area, shows the greatest potential for increased growth rates under the predicted warming and altered precipitation regime. White spruce is likely to benefit less, while the understory dominant balsam fir is likely to experience a decrease in growth potential. These projected changes would enhance the future status of sugar maple at its northern limit and facilitate range expansion northward in response to global warming.

Variations in the foliar amino acid composition of flowering and non-flowering balsam fir (Abies balsamea (L.) Mill.) and white spruce (Picea glauca (Moench) Voss) in relation to outbreaks of the spruce budworm (Choristoneura fumiferana (Clem))

1971 ◽  
Vol 49 (7) ◽  
pp. 1005-1011 ◽  
Author(s):  
J. P. Kimmins
Keyword(s):  
Amino Acids ◽  
Picea Glauca ◽  
Host Plants ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
Apparent Correlation

The amino acids of new and old foliage of flowering and non-flowering balsam fir (Abies balsamea (L.) Mill.) and white spruce (Picea glauca (Moench) Voss) were investigated using two-dimensional descending paper chromatography. The data were analyzed for variation associated with age of foliage, age of tree, and flowering condition. The concentration of foliar amino acids was greater in balsam fir than in white spruce, and greater in new foliage than old foliage.The difference in concentration between foliage of flowering and non-flowering trees was smaller. However, the new foliage of flowering fir had higher levels of most of the amino acids examined than any other foliage category. This appears to reflect the known suitability of these foliage categories for spruce budworm larvae. While the data presented do not quantify the ecological significance of this apparent correlation, they do support the theory that variations in the nutritional quality of host plants play a very important role in the dynamics of herbivore populations.

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