scholarly journals Development of a New TRIPLEX-Insect Model for Simulating the Effect of Spruce Budworm on Forest Carbon Dynamics

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 513 ◽  
Author(s):  
Zelin Liu ◽  
Changhui Peng ◽  
Louis De Grandpré ◽  
Jean-Noël Candau ◽  
Xiaolu Zhou ◽  
...  

The spruce budworm (SBW) defoliates and kills conifer trees, consequently affecting carbon (C) exchanges between the land and atmosphere. Here, we developed a new TRIPLEX-Insect sub-model to quantify the impacts of insect outbreaks on forest C fluxes. We modeled annual defoliation (AD), cumulative defoliation (CD), and tree mortality. The model was validated against observed and published data at the stand level in the North Shore region of Québec and Cape Breton Island in Nova Scotia, Canada. The results suggest that TRIPLEX-Insect performs very well in capturing tree mortality following SBW outbreaks and slightly underestimates current annual volume increment (CAI). In both mature and immature forests, the simulation model suggests a larger reduction in gross primary productivity (GPP) than in autotrophic respiration (Ra) at the same defoliation level when tree mortality was low. After an SBW outbreak, the growth release of surviving trees contributes to the recovery of annual net ecosystem productivity (NEP) based on forest age if mortality is not excessive. Overall, the TRIPLEX-Insect model is capable of simulating C dynamics of balsam fir following SBW disturbances and can be used as an efficient tool in forest insect management.

1989 ◽  
Vol 19 (9) ◽  
pp. 1087-1095 ◽  
Author(s):  
David A. MacLean ◽  
Donald P. Ostaff

Tree mortality caused by spruce budworm (Choristoneurafumiferana (Clem.)) defoliation was assessed annually from 1976 to 1985 in 20 mature balsam fir (Abiesbalsamea (L.) Mill.) stands on Cape Breton Island, Nova Scotia, and was related to defoliation and to tree, stand, and site characteristics. Ten to 12 years after the start of the budworm outbreak, fir mortality averaged 87% of the merchantable volume (range 60–100%) among the stands. Timing of mortality was similar to that found in studies of previous outbreaks. In the first 4 years of the outbreak, virtually all the trees that died had more than 90% cumulative defoliation but, overall, 64, 21, and 14% of the dead trees had cumulative defoliation >90, 76 to 90, and 51 to 75%, respectively. Early in the outbreak, fir mortality was generally negatively correlated with tree vigor, relative crown position, or diameter at breast height, but in later years, trees were killed irrespective of these factors. Fir mortality was evenly distributed among different sized trees, and 73 to 86% of the trees in each 5 cm diameter at breast height class died. A linear regression equation between dead fir volume and total fir volume explained 89% of the variability in mortality among stands. Percent fir mortality was correlated (r = 0.84) with visual estimates of cumulative defoliation (including all age-classes of foliage) in 1981, but mortality was not correlated with cumulative current annual defoliation or with site characteristics. Using regression equations, fir mortality during this budworm outbreak was predicted to within ±6 m2/ha in 14 of 18 (78%) of the stands, with a relative accuracy of 17.7%.


1983 ◽  
Vol 59 (1) ◽  
pp. 17-20 ◽  
Author(s):  
J. Robert Blais

Quebec's North Shore is a vast region comprising about one third of productive forests in the province. The impact of the spruce budworm (Choristoneura fumiferana (Clem.)) in this remote region was not welt known. In the summer of 1981, ground and aerial surveys were conducted to determine the extent to which fir stands had been affected during the current bud-worm outbreak. It was possible to confirm that defoliation had been severe for several successive years prior to 1978, and that since then, insect populations had diminished considerably. Available information on balsam fir mortality indicated only two areas: one in Saguenay River region in the extreme southwest of the study area, and the other in the vicinity of Baie Comeau. The 1981 surveys revealed that varying quantities of fir had succumbed to budworm attack in many stands occurring for hundreds of kilometers east of Baie Comeau. The spruce budworm maintained high populations sufficiently long to cause pockets of tree mortality over a widespread area on the North Shore. Growth-ring measurements on several old balsam fir and white spruce trees from many localities indicated that no other widespread budworm outbreak had occurred on the North Shore since the end of the nineteenth century.


1989 ◽  
Vol 19 (9) ◽  
pp. 1077-1086 ◽  
Author(s):  
Donald P. Ostaff ◽  
David A. MacLean

Effects of an uncontrolled spruce budworm (Choristoneurafumiferana (Clem.)) outbreak in 20 mature balsam fir (Abiesbalsamea (L.) Mill.) stands on Cape Breton Island, Nova Scotia, were studied from 1976 to 1985. Spruce budworm populations were extremely high, higher than peak levels recorded for other outbreaks, and averaged over 380 third-instar larvae per square metre of foliage from 1976 to 1980. As many as 1570 third-instar larvae per square metre occurred 5 to 7 years after the start of the outbreak, resulting in complete current defoliation and back-feeding on older foliage. Stands were divided into three groups, based on the pattern of cumulative current defoliation; the sum of current annual defoliation during the outbreak was 343, 445, and 543% for these groups, equivalent to the removal of 3.5 to 5.5 age-classes of foliage. Budworm defoliation caused the death of 78, 80, and 89% of the merchantable balsam fir volume in the three groups of stands, respectively, as well as 27% of the spruce (Picea sp.) volume; another 39% of the spruce volume died as a result of spruce beetle (Dendroctonusrufipennis Kby.) activity. Fir mortality commenced 3 years after the start of the outbreak and spruce mortality 2 to 3 years later. About one-half of the total mortality occurred in the 4 years after budworm populations and defoliation returned to low levels. Tree mortality and loss of foliage opened the stands, and 4 years after the collapse of the outbreak, 4% of the surviving trees and 17% of the dead trees had blown down, whereas 60% of all trees had broken tops.


1995 ◽  
Vol 25 (6) ◽  
pp. 902-911 ◽  
Author(s):  
David A. MacLean ◽  
Harald Piene

Spatial and temporal patterns of balsam fir (Abiesbalsamea (L.) Mill.) mortality were studied during a spruce budworm (Choristoneurafumiferana Clem.) outbreak from 1976 to 1984 on Cape Breton Island, Nova Scotia. Natural mortality in four insecticide-protected plots was 0% in spaced and 9–15% in unspaced stands, with only the smallest trees dying. Budworm-caused mortality (i.e., total minus natural) was 31–49% and 11–32% in spaced and unspaced young fir plots, respectively, but reached 94–100% in severely defoliated spaced plots, unprecedented in the literature for young fir mortality caused by the spruce budworm. Mortality began in the fourth to sixth year of defoliation, being earliest in the severely defoliated plots. From 80 to 90% of trees that died had > 75% cumulative defoliation, and most (64–100%) of the smallest (2 cm DBH) trees died. There was no significant difference in percent mortality between 25 spaced and 13 unspaced plots (p = 0.434), although, on average, mortality was 10–22% higher in the spaced plots. About 20–30% more of the intermediate-sized and largest trees were killed in the spaced plots. High spatial plot to plot variability in mortality occurred, which was apparently related to observed differences in the amount of defoliation and especially the incidence of "back-feeding" (damage to noncurrent foliage), as well as to plot size. Because budworm-caused mortality exhibits a distribution that tends to form large "holes" in stands, the degree of between-plot variability is related to plot size, and it is recommended that small plots that may miss these patches of mortality be avoided.


2007 ◽  
Vol 44 (11) ◽  
pp. 1551-1565 ◽  
Author(s):  
Lori A Cook ◽  
Sonya A Dehler ◽  
Sandra M Barr

A prominent positive magnetic anomaly spans the 100 km distance between Prince Edward Island and Cape Breton Island in the southern Gulf of St. Lawrence. The anomaly occurs in an area of complex structure where Appalachian terrane boundaries are poorly resolved because of thick late Paleozoic sedimentary cover. Analysis of the magnetic anomaly led to the interpretation that it is produced by four separate, approximately circular, source bodies aligned along the northwesterly trend of the anomaly. Seismic data, physical property measurements, and magnetic and gravity anomalies were used to further investigate the anomaly sources through forward modeling techniques. The four source bodies have densities and magnetic susceptibilities compatible with dioritic to granitic compositions. Modeling also suggests that basement to the north of the plutons has higher density and susceptibility than basement to the south, and hence the source bodies are interpreted as plutons emplaced along the boundary between Ganderian composite terranes to the north and the Ganderian Brookville – Bras d’Or terrane to the south. This interpretation suggests that the Ganderia–Avalonia boundary is located farther south, and shows the need for re-evaluation of the location and role of the Canso fault in offsetting terranes between Cape Breton Island and southern New Brunswick.


1995 ◽  
Vol 25 (7) ◽  
pp. 1128-1136 ◽  
Author(s):  
Donald P. Ostaff ◽  
David A. MacLean

Changes in foliar production caused by spruce budworm (Choristoneurafumiferana (Clem.)) defoliation and patterns of volume increment of surviving trees during and after the outbreak were determined in 20 mature balsam fir (Abiesbalsamea (L.) Mill.) stands on Cape Breton Island, Nova Scotia. Following the cessation of defoliation, the number of shoots increased 4-fold and mean shoot length doubled, resulting in a 12-fold increase in needle biomass. Average specific volume increment declined from 0.17–0.25 to 0.02–0.04 cm3•cm−2•year−1 after 4 years of severe defoliation; maximum increment reduction was 74–92%. Periodic radial increment and volume increment reduction (percent of mean increment in the previous decade) were both significantly related to cumulative (summed current annual) defoliation; a logistic regression equation explained 77% of the variation in volume loss. Differences in growth recovery among trees were determined by the temporal patterns of defoliation, with a 1-year lag before the beginning of volume increment recovery. Following 5 to 8 years of recovery, surviving trees had regained 48–82% of their predefoliation increment; however, absolute volume losses during the outbreak averaged 12–33 dm3/tree, or 32–48%.


1986 ◽  
Vol 23 (12) ◽  
pp. 1891-1901 ◽  
Author(s):  
R. A. Jamieson ◽  
O. van Breemen ◽  
R. W. Sullivan ◽  
K. L. Currie

Plutonic rocks of four different ages have been recognized in the Cape Breton Highlands on the basis of U–Pb dating of zircons. Two plutons, the North Branch Baddeck River leucotonalite [Formula: see text] and the Chéticamp pluton (550 ± 8 Ma), give dates that fall within the range of Late Proterozoic to Cambrian ages considered characteristic of the Avalon tectonostratigraphic zone of the eastern Appalachians. Late Ordovician to Silurian tonalite (Belle Côte Road orthogneiss, 433 ± 20 Ma) was metamorphosed, deformed, and incorporated into the central Highlands gneiss complex by approximately 370–395 Ma. High-level subvolcanic plutons (Salmon Pool pluton, [Formula: see text]) postdate all metamorphic rocks in the area. The presence of the older plutons is consistent with interpretation that the Cape Breton Highlands form part of the Avalon zone, but the presence of Ordovician–Silurian plutonic rocks and Devonian amphibolite-facies metamorphism is anomalous in comparison with the Avalon zone of Newfoundland and southeastern Cape Breton Island. Terranes with similar Late Proterozoic to mid-Paleozoic plutonic and metamorphic histories form a discontinuous belt along the northwest side of the Avalon zone southwest of Cape Breton Island. These rocks probably reflect events during and after the accretion of the Avalon zone to North America.


2011 ◽  
Vol 85 (4) ◽  
pp. 678-694 ◽  
Author(s):  
ED Landing ◽  
Richard A. Fortey

The Chesley Drive Group, an Upper Cambrian-Lower Ordovician mudstone-dominated unit, is part of the Ediacaran–Ordovician cover sequence on the North American part of the Avalon microcontinent. The upper Chesley Drive Group on McLeod Brook, Cape Breton Island (previously “McLeod Brook Formation”), has two lithofacies-specific Tremadocian biotas. An older low-diversity benthic assemblage (shallow burrowers, Bathysiphon, phosphatic brachiopods, asaphid trilobites) is in lower upper Tremadocian green-gray mudstone. This wave-influenced, slightly dysoxic facies has Bathysiphon–brachiopod shell lags in ripple troughs. The upper fauna (ca. 483 +/- 1 Ma) is in dysoxic-anoxic (d-a), unburrowed, dark gray-black, upper upper (but not uppermost) Tremadocian mudstone with a “mass kill” of the olenid Peltocare rotundifrons (Matthew)—a provincial trilobite in Avalonian North America that likely tolerated low oxygen bottom waters. Scandodus avalonensis Landing n. sp. and Lagenochitina aff. conifundus (Poumot), probable nektic elements and the first upper Tremadocian conodont and chitinozoan reported from Avalon, occur in diagenetic calcareous nodules in the dark gray-black mudstone. An upper Tremadocian transition from lower greenish to upper black mudstone is not exposed on McLeod Brook, but is comparable to a coeval green-black mudstone transition in Avalonian England. The successions suggest that late late Tremadocian (probable Baltic Hunnebergian Age) sea level was higher in Avalon than is suggested from successions on other paleocontinents. The Tremadocian sea-level history of Avalon was a shoaling-deepening-shoaling sequence from d-a black mudstone (lower Tremadocian), to dysoxic green mudstone (lower upper Tremadocian), and back to black mudstone (upper upper Tremadocian).Scandodus Lindström is emended, with the early species S. avalonensis Landing n. sp. assigned to the emended Family Protopanderodontidae. Triangulodus Van Wamel is considered a junior synonym of Scandodus. Peltocare rotundifrons is emended on the basis of complete specimens.


1984 ◽  
Vol 21 (7) ◽  
pp. 762-774 ◽  
Author(s):  
Marie-Claude Blanchard ◽  
Rebecca A. Jamieson ◽  
Elizabeth B. More

The Fisset Brook Formation of western Cape Breton Island and its equivalents at MacMillan Mountain and the north Baddeck River are examples of Late Devonian and Early Carboniferous volcanic sequences associated with the formation of post-Acadian successor basins in the northeastern Appalachians. They consist of bimodal basalt–rhyolite suites interbedded with alluvial fan, lacustrine, and rare fluvial sediments. The earliest volcanic products are rhyolites and somewhat evolved basalts associated with coarse sediments, followed by tholeiitic to transitional basalt flows interlayered with lacustrine-type deposits. Geochemical studies on the Fisset Brook Formation indicate extensive remobilization of alkalies, Ca, Rb, and Sr, making these elements inappropriate for determining tectonic setting or magmatic affinity. Use of less mobile elements (Ti, Nb, Y, and Zr) suggests that the basalts are tholeiitic and that the apparent alkalinity of the type section lavas is a result of alteration. We conclude that volcanism in western Cape Breton Island started at MacMillan Mountain and migrated westwards, probably towards the centre of the deepening Magdalen Basin.


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