A comparison of gap characteristics in mixedwood old-growth forests in eastern and western Quebec

2005 ◽  
Vol 35 (10) ◽  
pp. 2510-2514 ◽  
Author(s):  
Julie Messier ◽  
Daniel Kneeshaw ◽  
Mathieu Bouchard ◽  
André de Römer
Keyword(s):  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Canopy Gaps ◽  
Small Scale ◽  
Gap Dynamics ◽  
Mixed Stands ◽  
Old Growth ◽  
Gap Fraction ◽  
Old Growth Forests ◽  
Gap Characteristics

Canopy gaps play an important role in the dynamics of old-growth forests, although it is not well known how gap dynamics differ among regions. To further our understanding of natural gap dynamics in mixedwood forests, this study compares mixed stands located in eastern (Gaspésie region) and western (Témiscamingue region) Quebec. We tested whether the gap fraction in mixedwood stands was similar in these two regions. Data from field transects were used to characterize current canopy gaps, and aerial photos were used to contrast gap characteristics before and after the most recent spruce budworm (Choristoneura fumiferana Clem.) outbreak, which occurred from 1973 to 1991 in Gaspésie and from 1972 to 1984 in Témiscamingue. The current gap fraction was found to differ between the two regions: it varied from 2% to 48% with an average of 25.6% for the Gaspésie region and from 24% to 52% with an average of 36.6% for the Témiscamingue region. While the last spruce budworm outbreak coincided with a significant increase in canopy openings in the Témiscamingue region (p = 0.047), no such effect was observed in Gaspésie. These results suggest that the temporal pattern of small-scale disturbances can vary among regions, even when similar forest types are compared.

Dynamique de la sapinière à bouleau jaune de l'est après une épidémie de tordeuse des bourgeons de l'épinette

1999 ◽  
Vol 75 (3) ◽  
pp. 515-534 ◽  
Author(s):  
Pierre Pominville ◽  
Stéphane Déry ◽  
Louis Bélanger
Keyword(s):  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
The Other ◽  
Balsam Fir ◽  
Betula Alleghaniensis ◽  
White Birch ◽  
Yellow Birch ◽  
Mixed Stands ◽  
The Dead

An outbreak of spruce budworm, Choristoneura fumiferana (Clem.), occurred between 1974 and 1987, in Quebec, in the eastern balsam fir, Abies balsamea (L.) Mill, - yellow birch, Betula alleghaniensis Britton, ecoclimatic sub-domain. The effect of this disruption has been assessed in mesic balsam fir stands killed during the outbreak, in mesic balsam fir stands partially damaged and in the following stands, also partially damaged: mesic yellow birch – balsam fir stands, mesic white birch, Betulapapyrifera Marsh., - balsam fir stands, mesic balsam fir – yellow birch stands, mesic balsam fir – white birch stands and xeric balsam fir stands. To that effect, surveys were led before, immediately after, and about five years after the outbreak in two blocks that have not been protected with insecticides. These blocks, located in Charlevoix and in Shipshaw management units, are second growth stands originating from clearcuts which occured about 50 years ago. Approximately five years after the outbreak, abundant coniferous regeneration was found everywhere except in the mesic yellow birch –balsam fir stand and in the dead mesic balsam fir stand, where softwood represented less than 50% of the regeneration. On the other hand, young softwood stems were located under the regeneration of white birch and of mountain maple, Acer spicatum Lam, in dead balsam fir stands, in balsam fir – white birch stands, as well as in living balsam fir stands and under mountain maple in yellow birch – balsam fir stands and in balsam fir – yellow birch stands. Our age structures indicate that softwood advance growth was relatively rare in these stands. Thus, during the opening of the canopy by the spruce budworm, intolerant hard-woods and shrubs invaded the still available microsites. In the dead balsam fir stands, stocking of the dominant hardwood regeneration stems is equivalent to that of softwood. Thus, dead balsam fir stands are turning to mixed stands. Xeric stands will remain softwood stands since they show luxuriant softwood regeneration dominating in height. In the other stands, we will have to wait the harvest period before we can adequately assess succession.

Structure, composition, and diversity of old-growth black spruce boreal forest of the Clay Belt region in Quebec and Ontario

2003 ◽  
Vol 11 (S1) ◽  
pp. S79-S98 ◽  
Author(s):  
Karen Harper ◽  
Catherine Boudreault ◽  
Louis DeGrandpré ◽  
Pierre Drapeau ◽  
Sylvie Gauthier ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Picea Mariana ◽  
Black Spruce ◽  
Small Scale ◽  
Structural Development ◽  
Spruce Forest ◽  
Forest Stands ◽  
Old Growth ◽  
Old Growth Forest ◽  
Old Growth Forests

Old-growth black spruce (Picea mariana) boreal forest in the Clay Belt region of Ontario and Quebec is an open forest with a low canopy, quite different from what many consider to be "old growth". Here, we provide an overview of the characteristics of old-growth black spruce forest for three different site types on organic, clay, and coarse deposits. Our objectives were (1) to identify the extent of older forests; (2) to describe the structure, composition, and diversity in different age classes; and (3) to identify key processes in old-growth black spruce forest. We sampled canopy composition, deadwood abundance, understorey composition, and nonvascular plant species in 91 forest stands along a chronosequence that extended from 20 to more than 250 years after fire. We used a peak in tree basal area, which occurred at 100 years on clay and coarse sites and at 200 years on organic sites, as a process-based means of defining the start of old-growth forest. Old-growth forests are extensive in the Clay Belt, covering 30–50% of the forested landscape. Black spruce was dominant on all organic sites, and in all older stands. Although there were fewer understorey species and none exclusive to old-growth, these forests were structurally diverse and had greater abundance of Sphagnum, epiphytic lichens, and ericaceous species. Paludification, a process characteristic of old-growth forest stands on clay deposits in this region, causes decreases in tree and deadwood abundance. Old-growth black spruce forests, therefore, lack the large trees and snags that are characteristic of other old-growth forests. Small-scale disturbances such as spruce budworm and windthrow are common, creating numerous gaps. Landscape and stand level management strategies could minimize structural changes caused by harvesting, but unmanaged forest in all stages of development must be preserved in order to conserve all the attributes of old-growth black spruce forest. Key words: boreal forest, old growth, paludification, Picea mariana, structural development, succession.

COMPARATIVE EFFICACIES OF SINGLE AND DOUBLE APPLICATIONS OF COMMERCIAL BACILLUS THURINGIENSIS AGAINST THE SPRUCE BUDWORM CHORISTONEURA FUMIFERANA IN BALSAM FIR STANDS

1984 ◽  
Vol 116 (1) ◽  
pp. 101-102 ◽  
Author(s):  
O. N. Morris
Keyword(s):  
Bacillus Thuringiensis ◽  
Picea Glauca ◽  
Black Spruce ◽  
Biological Control Agent ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Spruce Budworm ◽  
Field Trials ◽  
Balsam Fir ◽  
Mixed Stands

Bacillus thuringiensis var. kurstaki (B.t.) is the most widely used biological control agent against the spruce budworm, Choristoneura fumiferana (Clem.), a major defoliator of coniferous forests. The technology of applying the bacterium, however, is still not fully developed and the strategy of applying single or split applications of B.t. in unmixed stands is still in question. Double applications are generally accepted as necessary in mixed stands of white spruce, Picea glauca (Moench) Voss, red spruce, P. rubens Sarg., black spruce, P. mariana (Mill.) BSP, and balsam fir, Abies balsamea (L.) Mill., due to difference in the phenological development of the host trees and of the budworm infesting them. Field trials were conducted at Mine Centre, Ontario, to compare the efficacies of double and single applications of B.t. against the budwonn infesting balsam fir stands.

Spatial characteristics of canopy disturbances in riparian old-growth hemlock – northern hardwood forests, Adirondack Mountains, New York, USA

2010 ◽  
Vol 40 (1) ◽  
pp. 13-25 ◽  
Author(s):  
Miranda T. Curzon ◽  
William S. Keeton
Keyword(s):  
New York ◽  
Linear Regression Analysis ◽  
Gap Dynamics ◽  
Adirondack Mountains ◽  
Old Growth ◽  
Tree Damage ◽  
Northern Hardwood ◽  
Gap Fraction ◽  
Successional Forests ◽  
Damage Type

Gap dynamics in temperate, late-successional forests influence important riparian functions, including organic matter recruitment and light environments over streams. However, controls on gap dynamics specific to riparian forests are poorly understood. We hypothesized that (i) gaps are larger and more frequent nearer streams, (ii) gaps cluster at within-stand scales, and (iii) tree damage type and gap fraction vary among riparian landforms. All gaps within four 6–9 ha plots in riparian old-growth eastern hemlock ( Tsuga canadensis (L.) Carrière) – northern hardwood forest in the Adirondack Mountains, New York, USA, were mapped and measured. We recorded species, damage type, and diameter at breast height for gapmakers and dominant perimeter trees. Spatial distribution was assessed with Ripley’s K. Spatial autocorrelation in gap area and tree damage type were assessed using Moran’s I. Linear regression analysis defined relationships between proximity to streams and gap area and frequency. Expanded gap fraction ranged from 28.3% to 47.6%. Gaps were randomly distributed at scales ≤25 m and clustered at scales of 63–122 m. Distribution patterns were not consistent at other scales. Convergent and divergent landforms significantly influenced gap fraction, tree damage type, and species distributions. Positive correlations between convergent topography and gap area suggest an interaction between low-order riparian landforms and gap formation dynamics in late-successional forests.

MONITORING OF ATMOSPHERIC CONCENTRATIONS OF THE SEX PHEROMONE OF THE SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA (LEPIDOPTERA: TORTRICIDAE)

1980 ◽  
Vol 112 (3) ◽  
pp. 333-334 ◽  
Author(s):  
C. J. Wiesner ◽  
P. J. Silk ◽  
S.-H. Tan ◽  
S. Fullarton
Keyword(s):  
Sex Pheromone ◽  
Sex Pheromones ◽  
Choristoneura Fumiferana ◽  
Spruce Budworm ◽  
Field Trials ◽  
Complex Problem ◽  
Small Scale ◽  
Atmospheric Concentration ◽  
Atmospheric Concentrations ◽  
Air Permeation

The disruption of insect mating with sex pheromones by the air permeation technique is a complex problem influenced by a number of variables. Not least among these is the actual atmospheric concentration of pheromone during the course of the experiment. While closely related to the measured release rate from a formulation, the atmospheric concentration should be regarded separately since a number of other factors may intervene, e.g., chemical instability, foliage adsorption, and the differential effects of formulation weathering in the laboratory and the field.The present study was conducted in conjunction with small scale field trials involving an aerially applied hollow fiber formulation of the sex pheromone of the spruce budworm, Choristoneura fumiferanu (Clem.), I1 -tetradecenal (97:3::E:Z). (Hereafter referred to as pheromone.)

scholarly journals Effects of Hardwood Content on Balsam Fir Defoliation during the Building Phase of a Spruce Budworm Outbreak

Forests ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 530 ◽  
Author(s):  
Bo Zhang ◽  
David MacLean ◽  
Rob Johns ◽  
Eldon Eveleigh
Keyword(s):  
Random Forests ◽  
Fixed Effects ◽  
Choristoneura Fumiferana ◽  
Abies Balsamea ◽  
Basal Area ◽  
Spruce Budworm ◽  
Analysis Data ◽  
Balsam Fir ◽  
Mixed Stands ◽  
Generalized Linear Mixed Effects

Defoliation by spruce budworm (Choristoneura fumiferana Clem.) on balsam fir (Abies balsamea (L.) Mill.) is more severe in fir than in mixed fir-hardwood stands. Previous studies assumed that defoliation in fir-hardwood stands was reduced in proportion to percent hardwood regardless of outbreak severity. We tested the influence of stand composition on defoliation during the first 5 years of a spruce budworm outbreak near Amqui, Quebec, by sampling 27 fir-hardwood plots selected to represent three percent hardwood basal area classes (0%–25%, 40%–65%, and 75%–95%). Balsam fir defoliation was significantly lower (p < 0.001) as hardwood content increased, but the relationship varied with overall defoliation severity each year. Annual plot defoliation in fir-hardwood plots, estimated using: (1) defoliation in pure fir plots and the assumption that defoliation in fir-hardwood plots was reduced in proportion to percent hardwood; (2) a generalized linear mixed-effects model with defoliation in pure fir plots, percent hardwood, and interaction as fixed-effects; and (3) Random Forests prediction incorporating 11 predictor variables, resulted in r = 0.77, 0.87, and 0.92 versus measured defoliation, respectively. Average defoliation severity in softwood plots and percent hardwood content were the most important variables in Random Forests analysis. Data on average defoliation level in softwood stands, as an indicator of overall outbreak severity, improves prediction of balsam fir defoliation in mixed stands.

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