A nonparametric survival model for balsam fir during a spruce budworm outbreak

1988 ◽  
Vol 18 (6) ◽  
pp. 789-795 ◽  
Author(s):  
Gregory A. Reams ◽  
Thomas B. Brann ◽  
William A. Halteman
Keyword(s):  
Basal Area ◽  
Spruce Budworm ◽  
Rate Of Change ◽  
Balsam Fir ◽  
Nonparametric Model ◽  
Base Line ◽  
Individual Tree ◽  
Instantaneous Rate ◽  
Force Of Mortality ◽  
General Mortality

A nonparametric model that relates spruce budworm (Choristoneurafumiferana (Clem.)) and blowdown-caused mortality of balsam fir trees (Abiesbalsamea (L.) Mill.) to individual tree and stand characteristics is presented. Estimation of the annual base-line hazard, λ0(t), also known in epidemiological research as the force of mortality or the instantaneous rate of death, provides an explicit estimate of the rate of change (accelerating or decelerating) of cause-specific mortality during the spruce budworm outbreak. Interpretation of the spruce budworm mortality model indicates that suppressed trees are more likely to survive than the other crown classes. In general, mortality caused by spruce budworm increased with increasing cumulative plot defoliation, increasing spruce (Picea spp.) and balsam fir basal area per hectare, and decreasing hardwood basal area per hectare. Interpretation of the blowdown model indicates that blowdown mortality generally increases with increasing balsam fir, spruce, and percent balsam fir basal areas per hectare and decreasing cumulative plot defoliation.

scholarly journals Spatial-Temporal Patterns of Spruce Budworm Defoliation within Plots in Québec

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 232 ◽  
Author(s):  
Mingke Li ◽  
David MacLean ◽  
Chris Hennigar ◽  
Jae Ogilvie
Keyword(s):  
Spatial Autocorrelation ◽  
Hot Spot ◽  
Basal Area ◽  
Temporal Patterns ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Tree Level ◽  
Cold Spot ◽  
Individual Tree ◽  
Tree Defoliation

We investigated the spatial-temporal patterns of spruce budworm (Choristoneura fumiferana (Clem.); SBW) defoliation within 57 plots over 5 years during the current SBW outbreak in Québec. Although spatial-temporal variability of SBW defoliation has been studied at several scales, the spatial dependence between individual defoliated trees within a plot has not been quantified, and effects of defoliation level of neighboring trees have not been addressed. We used spatial autocorrelation analyses to determine patterns of defoliation of trees (clustered, dispersed, or random) for plots and for individual trees. From 28% to 47% of plots had significantly clustered defoliation during the 5 years. Plots with clustered defoliation generally had higher mean defoliation per plot and higher deviation of defoliation. At the individual-tree-level, we determined ‘hot spot trees’ (highly defoliated trees surrounded by other highly defoliated trees) and ‘cold spot trees’ (lightly defoliated trees surrounded by other lightly defoliated trees) within each plot using local Getis-Ord Gi* analysis. Results revealed that 11 to 27 plots had hot spot trees and 27% to 64% of them had mean defoliation <25%, while plots with 75% to 100% defoliation had either cold spot trees or non-significant spots, which suggested that whether defoliation was high or low enough to be a hot or cold spot depended on the defoliation level of the entire plot. We fitted individual-tree balsam fir defoliation regression models as a function of plot and surrounding tree characteristics (using search radii of 3–5 m). The best model contained plot average balsam fir defoliation and subject tree basal area, and these two variables explained 80% of the variance, which was 2% to 5% higher than the variability explained by the neighboring tree defoliation, over the 3–5 m search radii tested. We concluded that plot-level defoliation and basal area were adequate for modeling individual tree defoliation, and although clustering of defoliation was evident, larger plots were needed to determine the optimum neighborhood radius for predicting defoliation on an individual. Spatial autocorrelation analysis can serve as an objective way to quantify such ecological patterns.

scholarly journals Spruce Budworm Defoliation and Growth Loss in Young Balsam Fir: Estimation of Volume Growth Based on Stem Analysis and Increment Cores at Breast Height

1996 ◽  
Vol 13 (2) ◽  
pp. 73-78 ◽  
Author(s):  
Harald Piene ◽  
Janine D'Amours ◽  
Alan A. Bray
Keyword(s):  
Volume Growth ◽  
Basal Area ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Stem Analysis ◽  
Individual Tree ◽  
Breast Height ◽  
Individual Tree Growth ◽  
Growth Loss ◽  
Changes Over Time

Abstract Comparisons of estimates of volume and volume increment, based on increment cores sampled at breast height and on stem analysis, were made in a young balsam fir stand that had been defoliated by spruce budworm. Use of increment cores is not recommended to estimate individual tree growth, because large errors, ranging from 20.9 to 57.2%, and error variability can be expected. The inability, when using increment cores, to estimate basal area is the major source of this variation. Although large uncertainties are associated with future growth predictions, on a per ha basis, changes over time based on increment cores may in some instances give comparable results to those based on stem analysis due to the canceling effect of trees being approximately equally overestimated and underestimated. However, a prerequisite is that the defoliation history and the year of individual tree death are known in detail to aid in the correct dating of ring widths. North. J. Appl. For. 13(2):73-78.

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.

One and two years impact of commercial thinning on spruce budworm feeding ecology and host tree foliage production and chemistry

1996 ◽  
Vol 72 (4) ◽  
pp. 393-398 ◽  
Author(s):  
Éric Bauce
Keyword(s):  
Choristoneura Fumiferana ◽  
Soluble Sugars ◽  
Abies Balsamea ◽  
Basal Area ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
First Year ◽  
Commercial Thinning ◽  
Mill Stand ◽  
Second Year

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

Balsam fir mortality following the last spruce budworm outbreak in northwestern Quebec

1995 ◽  
Vol 25 (8) ◽  
pp. 1375-1384 ◽  
Author(s):  
Yves Bergeron ◽  
Alain Leduc ◽  
Claude Joyal ◽  
Hubert Morin
Keyword(s):  
Stand Structure ◽  
Management Strategies ◽  
Basal Area ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Forest Composition ◽  
Regression Analyses ◽  
Site Characteristics ◽  
Forest Mosaic ◽  
Independent Effects

Balsam fir (Abiesbalsamea (L.) Mill.) mortality caused by the last spruce budworm (Choristoneurafumiferana (Clem.)) outbreak (1970–1987) was studied in 624 sites belonging to a complex natural forest mosaic originating from different fires in northwestern Quebec. Multiple regression analyses were used to assess the respective effects of stand structure, species composition, site characteristics, and the forest composition surrounding the stand on observed stand mortality. Mortality was observed to increase in relation to diameter of the trees, basal area of balsam fir, and the number of stands dominated by conifers in the forest mosaic. All of these factors showed significant independent effects, but 60% of the variance remained unexplained. Site characteristics, however, did not show a significant relationship to stand mortality. The results suggest that forest composition at both the stand and the forest mosaic levels may be responsible for differing degrees of defoliation that result in differences in stand mortality. Forest management strategies that favor the presence of mixed compositions both at the stand level and at the mosaic level may contribute to decreased stand vulnerability.

scholarly journals Forest Succession Following a Spruce Budworm Outbreak in Minnesota

1985 ◽  
Vol 61 (2) ◽  
pp. 75-80 ◽  
Author(s):  
Harold O. Batzer ◽  
Michael P. Popp
Keyword(s):  
Forest Succession ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Basal Area ◽  
Spruce Budworm ◽  
White Spruce ◽  
Balsam Fir ◽  
Red Maple ◽  
Shrub Species ◽  
Before And After

Plots in 24 spruce-fir stands in northeastern Minnesota studied throughout the period 1957 to 1962 at the time of a spruce budworm outbreak were remeasured in 1979. Composition of the overstory changed from an average of 79% of the basal area in host species before to 31% after the budworm outbreak. Twelve percent of the stands showed growth in nonhost species that more than offset the loss in balsam fir and white spruce. The understory was minimally stocked with balsam fir in two-thirds of the stands. Only 4% of the regeneration was spruce. Even so, some well-established white spruce seedlings were found in two-thirds of the stands. Red maple was the most abundant hardwood invader. Raspberry, hazel and mountain maple were the principal shrub species limiting balsam fir reproduction Shrubs were most abundant in stands where balsam fir mortality had exceeded 80%. Half of the stands had seedlings that originated both before and after the outbreak; 45% had seedlings that originated only after the outbreak; and 5% had seedlings that originated only before the outbreak. Stands having moderate mixture of nonhost species in the over-story prior to the budworm outbreak had the most balsam fir regeneration. This resulted from seed produced by surviving balsam fir trees after the outbreak. Key words: Choristoneura fumiferana, Abies balsamea, Balsam fir, spruce-fir shrubs

Relationships between balsam fir mortality caused by the spruce budworm and stand, site, and soil variables in Michigan's Upper Peninsula

1985 ◽  
Vol 15 (1) ◽  
pp. 141-147 ◽  
Author(s):  
Ann M. Lynch ◽  
John A. Witter
Keyword(s):  
Sugar Maple ◽  
Basal Area ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
National Forests ◽  
Red Maple ◽  
Upper Peninsula ◽  
Soil Variables ◽  
Stand Type ◽  
Northern White Cedar

The association of various stand, site, and soil variables with impact of the spruce budworm, Choristoneurafumiferana (Clemens), on balsam fir, Abiesbalsamea (L.) Mill., was examined in the Hiawatha and Ottawa National Forests of Michigan's Upper Peninsula. Geographic differences in impact were due, at least in part, to differences in the duration of the budworm outbreak. Impact was extremely variable between stands. Linear relations observed between impact variables and stand, site, and soil variables were weak. The quantity of balsam fir in the stand (basal area per hectare or proportion of stocking) was positively correlated with dead basal area per hectare but not with percent basal area mortality. Increased impact was associated with increased quantities of white pine (Pinusstrobus L.), northern white-cedar (Thujaoccidentalis L.), eastern hemlock (Tsugacanadensis (L.) Carr.), sugar maple (Acersaccharum L.), and red maple (Acerrubrum L.) in one or both of the National Forests. Drainage and soil moisture appeared to play a role in determining the amount of spruce budworm impact in individual stands. Principal components extracted from the stand data accounted for variability between different stand types. However, the between-stand variability in impact did not coincide with the between-stand-type variability described by the components.

Spruce Budworm Damage in Aspen/Balsam Fir Stands Affected by Cutting Methods

1987 ◽  
Vol 4 (2) ◽  
pp. 73-75 ◽  
Author(s):  
Harold O. Batzer ◽  
John W. Benzie ◽  
Michael P. Popp
Keyword(s):  
Basal Area ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Early Release ◽  
Growth Loss ◽  
Maximum Protection

Abstract An aspen/balsam fir study area in Wisconsin with several replicated cutting treatments dating from 1950 when the stand was 36 years old became infested by the spruce budworm in 1976. Remeasurement in 1981 revealed that balsam fir mortality and growth loss were directly related to the amount of aspen removed from the overstory. Complete and commercial clearcutting of the overstory aspen produced 60% more balsam fir basal area than uncut plots by 1975. However, mortality from budworm defoliation averaged 98% of the basal area in these plots. Thinning from above best achieved the objective of early release and provided near maximum protection from the spruce budworm. North. J. Appl. For. 4:73-75, June 1987.

The historical reconstruction of growth efficiency and its relationship to tree mortality in balsam fir ecosystems affected by spruce budworm

1994 ◽  
Vol 24 (11) ◽  
pp. 2208-2221 ◽  
Author(s):  
Marie R. Coyea ◽  
Hank A. Margolis
Keyword(s):  
Leaf Area ◽  
Tree Mortality ◽  
Basal Area ◽  
Spruce Budworm ◽  
Growth Efficiency ◽  
Balsam Fir ◽  
Tree Age ◽  
Basal Area Growth ◽  
Annual Growth Rings ◽  
Area Growth

The growth efficiencies (E; stemwood growth per unit leaf area) of balsam fir (Abiesbalsamea (L.) Mill.) trees from 20 stands were reconstructed over the 30-year period from 1960 to 1989 in order to determine if E could be used to predict tree mortality occurring during and after an epidemic of eastern spruce budworm (Choristoneurafumiferana (Clem.)). Growth efficiencies were reconstructed based on the relationship between age and the number of annual growth rings in the cross-sectional area of heartwood at breast height (R2 = 0.97) and on the previously demonstrated relationship between sapwood area and leaf area of balsam fir across a wide geographic area. Profile and logistic regression analyses demonstrated that apparent E (i.e., the historically reconstructed E) of surviving trees was greater than that of dead trees for every year of the 30-year analysis period. For trees in the 25- to 35-year age-class in 1960, apparent E was the only variable measured prior to the epidemic that was significantly related to balsam fir mortality. For all trees (aged 11 to 46 years in 1960), both tree age and apparent E were significant factors prior to the epidemic. During and following the epidemic, several of the more standard mensurational variables (e.g., diameter and basal area growth) were also significantly associated with balsam fir mortality, but apparent E had the highest levels of significance. Using logistical regression, critical E values below which trees would be predicted to die were calculated as 5-year running averages for the period prior to the epidemic (1960–1968). These were stable at around 0.17 × 10−4 m2 basal area growth•(m2 leaf area)−1•year−1. Following the epidemic, critical E values were again stable but at a lower level of around 0.07. There was a negative exponential relationship between apparent E and leaf area. Furthermore, for the same level of leaf area, surviving trees had a higher apparent E than trees that died, up to approximately 30 m2 of leaf area. These results suggest that growth efficiency should be considered as part of standard forest inventories in the balsam fir zone because of its ease of measure and its apparent ability to provide a sensitive, physiologically based index of forest health. Furthermore, the technique of historically reconstructing E demonstrated in this study may be of interest for other types of dendrochronological research.

scholarly journals Impact of a spruce budworm outbreak in balsam fir and subsequent stand development over a 40-year period

2008 ◽  
Vol 84 (1) ◽  
pp. 60-69 ◽  
Author(s):  
David A MacLean ◽  
Allison R Andersen
Keyword(s):  
Stand Structure ◽  
Abies Balsamea ◽  
Basal Area ◽  
Stand Density ◽  
Spruce Budworm ◽  
Balsam Fir ◽  
Stand Development ◽  
Wide Range ◽  
Break Up ◽  
The Impact

Nine 0.04-ha plots were established in 1956 (age 35 years) in a balsam fir (Abies balsamea [L.] Mill.) stand in northwestern New Brunswick, Canada to determine the impact of an uncontrolled spruce budworm (Choristoneura fumiferana [Clem.]) outbreak on stand development. The plots were measured annually from 1956 to 1961 and at five-year intervals from 1965 to 1995. Moderate to severe defoliation occurred from 1951 to 1957 and again in 1975 to 1977, 1981, and 1986 to 1988. Budworm-caused mortality from 1956 to 1961 (age 35 to 40 years) varied considerably among plots, reducing volume by 35 to 113 m3/ha (34%-84%), and resulting in a wide range of post-outbreak plot densities. Plots were grouped into three post-budworm outbreak (1965, age 45 years) basal area classes, of ≤ 20 m2/ha, 21 to 27 m2/ha, and ≥ 28 m2/ha, to examine stand recovery. Recovery of volume up to age 60 years ranged from 72 to 132 m3/ha, in the lowest to highest basal area classes, respectively. From age 60 to 75 years, five plots declined in volume due to the onset of stand break-up and four plots increased in volume. By age 60 years, survivor growth was greatest in the high basal area plots, ranging from 6.2 to 9.0 m3/ha/yr in seven plots, versus 2.6 to 3.2 m3/ha/yr in two low basal area plots. From age 60 to 75 years, survivor growth averaged only 2.8 to 5.2 m3/ha/yr, and the stand exhibited major decline, with 63%, 74%, and 78% mortality of fir ≤ 15 cm DBH in the low to high basal area plots, respectively. Budworm-caused "thinning" in the 1950s largely determined subsequent stand development and the rate of stand break-up 25 to 35 years later. The timing and rate of natural stand decline was strongly influenced by post-outbreak stand density. Key words: budworm-caused mortality, stand structure, stand development, growth, mortality, stand density

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