Habitat requirements of the Yellow-bellied Sapsucker, Sphyrapicus varius, in boreal mixedwood forests of northwestern Canada

2006 ◽  
Vol 84 (9) ◽  
pp. 1230-1239 ◽  
Author(s):  
C. Savignac ◽  
C.S. Machtans
Keyword(s):  
Populus Tremuloides ◽  
Keystone Species ◽  
Forest Harvesting ◽  
Habitat Requirements ◽  
Northwestern Part ◽  
Strongly Correlated ◽  
Mixedwood Forests ◽  
Nesting Sites ◽  
Site Use ◽  
Paper Birch

Despite its role as a keystone species, few studies have investigated the habitat requirements of the Yellow-bellied Sapsucker ( Sphyrapicus varius (L., 1766)) in the northwestern part of its range, where the current forest harvesting rotation schedule and targets for reducing the prevalence of old and mixedwood stands may reduce the optimal habitat for this species. We studied nesting and foraging habitat requirements of nesting sapsuckers in a boreal mixedwood forest of northwestern Canada by collecting data on nesting sites and foraging substrates on twenty-four 16- to 56-ha plots distributed among four habitat types in 1998 and 2002. Nests (n = 68) were generally found in large (≥22 cm diameter at breast height) trembling aspen ( Populus tremuloides Michx) that were alive but declining and that showed high incidence (81.1%) of heartwood rot infection ( Phellinus tremulae (Bondarzev) Bondarzev & Borisov in Bondarzev). Nest-site use by sapsuckers was predicted mainly by the presence of external fungal conks and tree diameter. Among tree species used as foraging substrates, paper birch ( Betula papyrifera Marsh.) (65.6%) and green alder ( Alnus viridis (Vill.) Lam. & DC.) (21.3%) were used most frequently. The use of birch was strongly correlated with its availability. Mature forests had higher densities of nesting sites and foraging substrates than immature aspen stands. In addition to reconfirming the importance of mature mixedwood forests for Yellow-bellied Sapsuckers, our study also indicates that forest harvest rotations in northwestern Canada should exceed 90 years to promote the keystone role of this species.

scholarly journals Spatial and temporal patterns of Populus tremuloides regeneration in small forest openings in northern Ontario

2009 ◽  
Vol 85 (4) ◽  
pp. 548-557 ◽  
Author(s):  
Arthur Groot ◽  
Rongzhou Man ◽  
Jim Wood
Keyword(s):  
Populus Tremuloides ◽  
Tree Height ◽  
Forest Harvesting ◽  
Trembling Aspen ◽  
Spatial And Temporal Patterns ◽  
Northern Ontario ◽  
Mixedwood Forests ◽  
Boreal Mixedwoods ◽  
Silvicultural System ◽  
Forest Openings

The density, height and diameter of trembling aspen sucker regeneration was assessed over a 10-year period in openings created by harvesting in a 40-year-old, 19-m-tall aspen stand in northeastern Ontario. The 5 types of opening comprised: circular openings of 9-m- and 18-m-diameter, 150-m-long east–west strips of 9-m and 18-m width, and a 1.5 ha (100 m × 150 m) clearcut. Density of aspen regeneration was significantly affected by opening type, location relative to the opening, time since harvest, and by all interactions of these factors. Aspen densities within the circular openings declined to low levels by year 10, despite considerable initial recruitment. Trembling aspen height and diameter were significantly influenced by opening type, location relative to the opening, time since harvest, and by opening × time and location × time interactions. Trembling aspen heights in the circular openings were substantially less than in the clearcut and strip openings by year 10. The results support the traditional view that aspen is best managed under the clearcut silvicultural system, and that trembling aspen regeneration following forest harvesting can be reduced by controlling the extent or intensity of overstory removal. Finally, the results suggest that disturbances that create gaps greater than 1 tree height in width in aspen or mixedwood forests may allow gap dynamics to function. Key words: trembling aspen, silviculture, boreal mixedwoods, regeneration, forest openings

scholarly journals Standing deadwood for keystone bird species in the eastern boreal forest: Managing for snag dynamics

2009 ◽  
Vol 85 (2) ◽  
pp. 227-234 ◽  
Author(s):  
Pierre Drapeau ◽  
Antoine Nappi ◽  
Louis Imbeau ◽  
Michel Saint-Germain
Keyword(s):  
Boreal Forest ◽  
Bird Species ◽  
Keystone Species ◽  
Biodiversity Loss ◽  
Forest Harvesting ◽  
Ecological Processes ◽  
Forestry Practices ◽  
Tree Retention ◽  
Management Approaches ◽  
Managed Landscapes

Extensive even-aged management of the boreal forest and its consequences on the loss of late-seral stages (>100 years) is raising concerns about the future of organisms associated with standing deadwood. The considerable reduction of deadwood not only at the stand but at the landscape level is considered to be one of the principal causes of biodiversity loss in managed forest ecosystems worldwide. Ecosystem-oriented management approaches propose a fundamental change in forestry practices whereby live and dead tree retention becomes an important consideration in forest harvesting. We use woodpecker assemblages and their association with standing deadwood for both nesting and foraging to emphasize the importance of the entire range of snag degradation stages for maintenance of key ecological processes in habitat remnants of managed landscapes. We argue that bridging foraging and nesting knowledge of woodpecker’s snag requirements can refine conservation objectives for deadwood retention in the boreal forest. Key words: deadwood, woodpeckers, hole-nesting community, late-seral forests, keystone species, foraging and nesting tree requirements, food webs, nest webs, snag management

Development of an improved model estimating the nutrient content of the bole for four boreal tree species

1998 ◽  
Vol 28 (1) ◽  
pp. 37-43 ◽  
Author(s):  
P Rochon ◽  
D Paré ◽  
C Messier
Keyword(s):  
Populus Tremuloides ◽  
Tree Species ◽  
Picea Glauca ◽  
Nonlinear Models ◽  
Abies Balsamea ◽  
Nutrient Content ◽  
Forest Harvesting ◽  
Nutrient Concentrations ◽  
Nutrient Contents ◽  
Improved Model

An improved model for estimating nutrient contents of the commercial portion of tree boles was developed for four boreal tree species (Populus tremuloides Michx., Betula papyrifera Marsh., Picea glauca (Moench) Voss, and Abies balsamea (L.) Mill.). This model considers the spatial pattern of variation of nutrient concentrations inside the bole and its relationships with tree size. For all species-nutrient combinations, no significant pattern was found for vertical variations in nutrient concentrations, while two types of nonlinear models, using distance from the tree periphery as the independent variable, fit the pattern of horizontal (or radial) variations. These patterns of variability were used to estimate the global nutrient concentration of the bole by using mathematical integration. The values obtained with this method were generally lower, especially for large stems, than values obtained with traditional methods that do not consider the variability of nutrient concentrations inside the bole. This improved model would permit better estimates of the amounts of nutrients lost in biomass upon forest harvesting, as well as internal cycling of nutrients within the bole.

Are mixtures of aspen and white spruce more productive than single species stands?

1999 ◽  
Vol 75 (3) ◽  
pp. 505-513 ◽  
Author(s):  
Rongzhou Man ◽  
Victor J. Lieffers
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
White Spruce ◽  
Single Species ◽  
Physical Separation ◽  
Soil Resource ◽  
Mixedwood Forests ◽  
Environmental Extremes ◽  
Spruce Stands ◽  
Boreal Mixedwoods

In boreal mixedwood forests, aspen (Populus tremuloides) and white spruce (Picea glauca) commonly grow in mixture. These species may avoid competition through differential shade tolerance, physical separation of canopies, phenological differences, successional separation, and differences in soil resource utilization. Aspen may also be able to positively affect the growth of white spruce by improving litter decomposition and nutrient cycling rates, controlling grass and shrub competition, ameliorating environmental extremes, and reducing pest attack. These positive relationships likely make mixed-species stands more productive than pure stands of the same species. The evidence regarding the productivity of pure versus mixed aspen/white spruce stands in natural unmanaged forests is examined in this paper. Key words: Tree mixture; productivity; boreal mixedwoods; aspen; white spruce

Patterns of initial versus delayed regeneration of white spruce in boreal mixedwood succession

2006 ◽  
Vol 36 (6) ◽  
pp. 1597-1609 ◽  
Author(s):  
Vernon S Peters ◽  
S Ellen Macdonald ◽  
Mark RT Dale
Keyword(s):  
Populus Tremuloides ◽  
Picea Glauca ◽  
Fire Severity ◽  
Mineral Soil ◽  
White Spruce ◽  
Mixedwood Forests ◽  
Regeneration Period ◽  
Postfire Regeneration ◽  
Distance To Seed Source ◽  
Mixedwood Stands

The timing of white spruce regeneration in aspen (Populus tremuloides Michx.) – white spruce (Picea glauca (Moench) Voss) boreal mixedwood stands is an important factor in stand development. We examined boreal mixedwood stands representing a 59-year period of time since fire and determined (1) whether and when a delayed regeneration period of white spruce occurred, (2) whether the relative abundance of initial (<20 years) versus delayed (≥20 years postfire) regeneration is related to seed availability at the time of the fire, and (3) what are the important regeneration substrates for initial versus delayed regeneration. Initial regeneration occurred primarily on mineral soil or humus, while delayed regeneration established primarily on logs and peaked 38–44 years after fire. Of the 20 stands investigated, seven were dominated by initial regeneration, six were dominated by delayed regeneration, and seven were even mixtures of both. The dominance of a site by initial or delayed regeneration could not be simply explained by burn timing relative to mast years or distance to seed source; our results suggested that fire severity and the competitive influence of initial regeneration on delayed regeneration were important at fine scales. Based on our results we describe several possible postfire successional pathways for boreal mixedwood forests.

Forest harvesting impacts on soil properties and vegetation communities in the Northwest Territories

2002 ◽  
Vol 32 (4) ◽  
pp. 713-724 ◽  
Author(s):  
Michael D Bock ◽  
Ken CJ Van Rees
Keyword(s):  
Species Composition ◽  
Soil Properties ◽  
Forest Harvesting ◽  
Understory Vegetation ◽  
Vegetation Community ◽  
Clear Cut ◽  
Mixedwood Forests ◽  
Crown Cover ◽  
Composition And Structure ◽  
Harvesting Systems

Management of boreal mixedwood forests in Canada has traditionally relied almost exclusively on the clear-cut silvicultural system. In recent years, greater utilization of the hardwood component of boreal mixedwoods and increased societal concerns over maintenance of the integrity and sustainability of these ecosystems has provided impetus for forest managers to consider alternative silvicultural practices in boreal mixedwood forests. Little is currently known, however, concerning the response of soils and vegetation to forest harvesting systems in the mixedwood forests of the Liard River valley, Northwest Territories (NWT). Therefore, the objective of this study was to quantify the effects of patch clear-cut, strip clear-cut, and clear-cut harvesting systems on soil properties and understory vegetation composition and structure. Treatment sites with 3 or 4 years of recovery since harvesting and adjacent uncut forest sites were sampled using transect methodology. Soil samples were collected and understory vegetation community species composition and percent crown cover were assessed in 1-m2 quadrats. Compared with the range of conditions present in the uncut forest, increases in mineral soil bulk density (2%), exchangeable calcium (7%), LFH horizon thickness (13%), pH (0.2 units), and total organic carbon (5%) and decreases in LFH horizon total nitrogen (6%) and exchangeable potassium (22%) were observed following harvesting. Harvesting resulted in the reduction in crown cover of feathermoss species and increased abundance of shrub and herb species and minimal changes to species composition. Multivariate analysis of the data indicated that the method of harvesting did not result in significant differences in species composition and structure of the understory vegetation community. Overall, winter harvesting of these boreal mixedwood sites did not have a major impact on the majority of soil properties evaluated or on the species composition of the understory vegetation community.

scholarly journals Contrasting Release Approaches for a Mixed Paper Birch (Betula papyrifera)–Quaking Aspen (Populus tremuloides) Stand

2008 ◽  
Vol 25 (3) ◽  
pp. 124-132 ◽  
Author(s):  
Eric K. Zenner ◽  
Klaus J. Puettmann
Keyword(s):  
Populus Tremuloides ◽  
Basal Area ◽  
Complete Removal ◽  
Quaking Aspen ◽  
Betula Papyrifera ◽  
Mixed Stands ◽  
Early Release ◽  
Paper Birch ◽  
Area And Volume

Abstract Early release from competitors can be used to influence the species composition, quality, and rate of development of young stands. Release strategies can vary in intensity, ranging from complete removal of competitors and infrequent future entries (early, heavy, infrequent [EHI]) to lighter entries that are repeated more frequently (early, light, often [ELO]). It is unclear, however, which strategy is more successful for producing high-quality birch sawtimber (Betula papyrifera Marsh.) in mixed stands with aspen (Populus tremuloides Michx.). We evaluated the effects of various release intensities on the growth and mortality of a 16–18-ft-tall natural aspen–paper birch stand in Minnesota following density reductions from 1,500–3,000 trees ac−1 (trees per acre [TPA]) to 750 (ELO750), 500 (EHI500), and 250 (EHI250) TPA. After 6 years, paper birch was overtopped by aspen and contributed only 14% of basal area in control plots, but it occupied all diameter classes and contributed 77–87% of basal area in release plots. The basal area and volume of all paper birch and of only paper birch crop trees (100 largest TPA) were highest in lightly released ELO750 and lowest in control plots. Growth of mean quadratic diameter, basal area, and volume of paper birch was 2–3 times higher in release plots but independent of release intensity. Early release is necessary to maintain paper birch dominance, but there is no short-term advantage among treatment intensities. Long-term growth simulations using the Forest Vegetation Simulator suggest that merchantable timber production was unaffected by release strategy but that the EHI250 strategy produced the most birch sawtimber (40 times as much as in ELO750).

Ectomycorrhizal colonization of greenhouse-grown Douglas-fir (Pseudotsuga menziesii) seedlings by inoculum associated with the roots of refuge plants sampled from a Douglas-fir forest in the southern interior of British Columbia

2004 ◽  
Vol 82 (6) ◽  
pp. 742-751 ◽  
Author(s):  
Shannon M Hagerman ◽  
Daniel M Durall
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Populus Tremuloides ◽  
Arbuscular Mycorrhizal ◽  
Douglas Fir ◽  
Fungal Colonization ◽  
Inoculum Potential ◽  
Paper Birch ◽  
Salix Bebbiana ◽  
Ectomycorrhizal Morphotypes

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were grown in the greenhouse in a sterilized mixture of forest soil and vermiculite, which had been inoculated with root fragments from one of six different ectomycorrhizal under story plant species (Arctostaphylos uva-ursi (L.) Spreng, P. menziessi, Salix bebbiana Bebb, Alnus viridis subsp. sinuata (Regel) Ä. Löve & and D. Löve (alder), Betula papyrifera Marsh. (paper birch), Populus tremuloides Michx.) and arbuscular mycorrhizal Calamagrostis rubescens Buckl. (pinegrass) sampled from a dry Douglas-fir forest in the southern interior of British Columbia. The overall objective of the present study was to investigate the inoculum potential of these ectomycorrhizal roots for colonizing Douglas-fir seedlings. A total of seven ectomycorrhizal morphotypes formed on the bioassay seedlings, which were colonized by all treatments except the control. Seedlings growing in soil inoculated with root fragments of Douglas-fir, Arctostaphylos, and paper birch had greater ectomycorrhizal richness and a higher percentage of colonized fine roots relative to the pinegrass and alder treatments. The community of ectomycorrhizal fungi that colonized the bioassay seedlings differed from that associated with some of the same refuge plants assessed in a previously reported field-based study at this site. Different ectomy corrhizal fungal colonization strategies and the retention of refuge plants are discussed in relation to the colonization of outplanted seedlings following clearcutting.Key words: ectomycorrhizae, refuge plants, inoculum potential, soil bioassay, Pseudotsuga menziesii.

Consequences of elevated carbon dioxide and ozone for foliar chemical composition and dynamics in trembling aspen (Populus tremuloides) and paper birch (Betula papyrifera)

2001 ◽  
Vol 115 (3) ◽  
pp. 395-404 ◽  
Author(s):  
Richard L. Lindroth ◽  
Brian J. Kopper ◽  
William F.J. Parsons ◽  
James G. Bockheim ◽  
David F. Karnosky ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Chemical Composition ◽  
Populus Tremuloides ◽  
Elevated Carbon Dioxide ◽  
Betula Papyrifera ◽  
Trembling Aspen ◽  
Paper Birch
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