Stand-level response of breeding forest songbirds to multiple levels of partial-cut harvest in four boreal forest types

2005 ◽  
Vol 35 (7) ◽  
pp. 1553-1567 ◽  
Author(s):  
R Bruce Harrison ◽  
Fiona K.A Schmiegelow ◽  
Robin Naidoo
Keyword(s):  
Boreal Forest ◽  
Natural Disturbance ◽  
Partial Cutting ◽  
Clear Cutting ◽  
Partial Harvesting ◽  
Undisturbed Forest ◽  
Forest Songbirds ◽  
Multiple Levels ◽  
Partial Retention ◽  
Forest Habitats

We investigated whether impacts on boreal forest songbird communities in northwestern Alberta could be mitigated through a harvesting system that attempts to emulate the local natural disturbance regime. The EMEND (Ecosystem Management by Emulating Natural Disturbance) project is a multidisciplinary experiment to compare clearcuts and partial-retention cuts in four upland cover types with uncut forest and with experimentally burned stands. We studied breeding birds at EMEND between 1998 (pretreatment) and 2000, focusing on their responses to partial harvesting. Partial cuts were generally intermediate (and varied in a linear fashion) between clearcuts and undisturbed forest for community and species measures. Species that declined in abundance in partial cuts were typically dependent on shrubs and trees, whereas species that benefited were typically ground nesters. While partial cutting offered some advantages over clear-cutting in conserving short-term avian diversity, we suggest that low retention levels (i.e., 10%, 20%) cannot be justified from this perspective. The benefits that accrued in these treatments were relatively small, and species that declined or disappeared were typically characteristic of mature forest habitats. Higher retention levels (i.e., 50%, 75%) may conserve some species of concern, but the extent to which these treatments offer productivity advantages over lower residuals requires further study.

scholarly journals Partial harvesting in the Canadian boreal: Success will depend on stand dynamic responses

2007 ◽  
Vol 83 (3) ◽  
pp. 319-325 ◽  
Author(s):  
H C Thorpe ◽  
S C Thomas
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Biological Diversity ◽  
Empirical Studies ◽  
Natural Disturbance ◽  
Dynamic Responses ◽  
Post Harvest ◽  
Partial Harvest ◽  
Partial Harvesting ◽  
Structural Retention

In the past 10 to 15 years, alternative silvicultural treatments involving partial harvesting have been developed for boreal forests, with the goal of achieving a balance between biodiversity maintenance and continued timber production. Most prior research has focussed on the impacts of partial harvesting on biological diversity, while stand dynamic responses remain little studied. In this paper we explore partial stand harvesting in the Canadian boreal—its rationale, current extent, and impact on stand dynamic patterns. Empirical studies from the boreal and elsewhere indicate that residual trees of many species respond to partial harvesting with enhanced growth, commonly showing a lagged response after which peak growth occurs five to 25 years following harvest. Post-harvest mortality is also prevalent but much more variable, with losses of residual trees ranging from nearly zero to more than 50% above background mortality rates in the initial years following harvest. With the exception of strip cutting in parts of northern Ontario and Quebec (HARP/CPPTM), operational partial harvesting in the Canadian boreal currently involves very low levels of retention. Available data suggest that such low retention levels, particularly when spatially dispersed, generally result in unacceptably high rates of post-harvest mortality, which are unlikely to be offset by increases in residual tree growth. There is an urgent need for development of spatially explicit stand simulation models that will allow accurate yield predictions for partial harvest systems to assess their feasibility in boreal forest management. Key words: ecosystem management, natural disturbance emulation, boreal forest, partial cut, structural retention, growth response, windthrow, post-harvest mortality

Effects of experimental harvesting on spider (Araneae) assemblages in boreal deciduous forests

2008 ◽  
Vol 140 (4) ◽  
pp. 437-452 ◽  
Author(s):  
Christopher M. Buddle ◽  
David P. Shorthouse
Keyword(s):  
Indicator Species ◽  
Boreal Forests ◽  
Large Scale ◽  
Wolf Spider ◽  
Natural Disturbance ◽  
Old Growth ◽  
Partial Cutting ◽  
Clear Cutting ◽  
Old Growth Forests ◽  
Geographic Separation

AbstractTwo large-scale forestry experiments, in Quebec (Sylviculture et aménagement forestiers écosystémique (SAFE)) and Alberta (Ecosystem Management by Emulating Natural Disturbance (EMEND)), were established in the late 1990s to test the effects of alternative silvicultural strategies (e.g., partial cutting) on biodiversity in northern boreal forests. We collected spiders in pitfall traps 2 years after the application of partial-cutting treatments in deciduous stands at EMEND and 6 years after similar treatments in deciduous stands at SAFE. Although we are aware of the challenges imposed by disparate locations and whole-scale experimental methods, our objective was to compare the effects of partial cutting on spider assemblages (diversity and community composition), and in doing so, to formulate a few general statements. Overall, 98 species (6107 individuals) were collected from Alberta and 86 species (3414 individuals) from Quebec. Of these, 44 species were common to both regions. Ordination and indicator-species analyses revealed a distinct effect of geographic separation: the spider assemblages in deciduous stands within the boreal plains ecoregion of Alberta and the boreal shield in Quebec were distinct. However, the effects of partial cutting on spider assemblages within each project were similar: removal of 25%–33% of trees shifted a characteristic old-growth fauna toward one more typical of clearcuts. Indicator-species analysis also revealed the dominance of wolf spider (Lycosidae) species in clearcuts within both experiments and we present evidence that clear-cutting homogenizes spider assemblages. Old-growth forests contain spider faunas that are easily disrupted by moderate partial cutting. In the face of intense harvesting practices, managing for the maintenance of biodiversity and conservation of spider faunas in northern forests will require retention of old-growth forests.

Marten use of clear-cuttings and residual forest stands in western Newfoundland

1987 ◽  
Vol 65 (1) ◽  
pp. 169-174 ◽  
Author(s):  
Joyce E. Snyder ◽  
John A. Bissonette
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Abies Balsamea ◽  
Balsam Fir ◽  
Primary Method ◽  
Forest Operations ◽  
Clear Cutting ◽  
Undisturbed Forest ◽  
Forest Habitats ◽  
Capture Rates

Marten (Martes americana) inhabit primarily old-growth coniferous and mixed wood forest habitats. Widespread forest harvest operations have prompted inquiries into whether residual patches of forest left after harvesting, or regenerating clear-cuttings, provide adequate habitat for marten. In western Newfoundland, the primary method of tree harvest has been clear-cutting of large tracts of balsam fir (Abies balsamea) and black spruce (Picea mariana). The only remaining populations of marten in the province also are found in the western part of the island, with greatest densities near Little Grand Lake. This study was designed to determine if marten used regenerating clear-cuttings and small remnant patches of residual forest left after forest operations. Habitat use by marten was investigated by livetrapping and snow tracking. Residual stands were classified into five size categories, and clear-cuttings into three categories based on height of balsam fir regeneration. From June to December 1983, marten were trapped in 43 residual stands and 35 clear-cuttings. A total of 3587 trap nights yielded 57 captures of 10 male and 8 female marten. Six (10.5%) captures were in clear-cuttings, all <15 years old; 51 (89.5%) marten were captured in residual stands. Capture rates were 0.48 captures/100 trap nights in the clear-cuttings and 2.19 captures/100 trap nights in residual stands. Capture rates were greatest in residual stands 25 to 34.9 ha in size (4.62 captures/100 trap nights). From January to March 1984, marten tracks were followed for 29 km. Although clear-cuttings represented 41 % of the study area, only 26% of marten travel was recorded there, all in clear-cuttings <15 years old. Residual stands >25 ha and undisturbed forest composed 41.3% of the study area; 41.8% of marten travel was recorded there. Smaller residual areas (<25 ha) made up only 4.2% of the total area, but 32.4% of the marten travel was recorded in these areas. These data indicate that marten seldom used clear-cuttings and used residual stands >25 ha and undisturbed forests in proportion to their occurrence, but the use of smaller residual stands <25 ha was greater than expected.

Song pitch – habitat relationships in white-throated sparrows: cracks in acoustic windows?

1988 ◽  
Vol 66 (11) ◽  
pp. 2578-2581 ◽  
Author(s):  
Joseph R. Waas
Keyword(s):  
Boreal Forest ◽  
Inverse Relationship ◽  
Habitat Type ◽  
Zonotrichia Albicollis ◽  
Acoustic Window ◽  
Wrong Reason ◽  
Foliage Density ◽  
The Right ◽  
Forest Habitats

I compared the hypothesis that birds singing from song posts above 1–2 m should sing in as low a pitch as possible regardless of habitat type, with the traditional "acoustic window" hypothesis which argues that selection favours an inverse relationship between song pitch and foliage density. Songs of white-throated sparrows, Zonotrichia albicollis, were obtained from four habitats which could be arranged in a gradient of foliage density. The pitch of these songs was found to be inversely related to the density of foliage in the habitat occupied, consistent with the acoustic window hypothesis. Significant pitch variation occurred not only between open and forest habitats, but also between mixed and boreal forest habitats. I distinguish between hypotheses that could explain support for the traditional hypothesis despite recent data suggesting that low pitched sound travels best regardless of habitat at song post heights used by white-throated sparrows (5–10 m). I conclude that the acoustic window model may make the right prediction for the wrong reason in white-throated sparrows. I emphasize the need to define and test the assumptions of models before the models themselves are accepted on the basis of support for their predictions.

Logging impacts on the biogeochemistry of boreal forest soils and nutrient export to aquatic systems: A review

2008 ◽  
Vol 16 (NA) ◽  
pp. 157-179 ◽  
Author(s):  
David P. Kreutzweiser ◽  
Paul W. Hazlett ◽  
John M. Gunn
Keyword(s):  
Boreal Forest ◽  
Nutrient Availability ◽  
Soil Nutrient ◽  
Soil Conditions ◽  
Soil Nutrient Availability ◽  
Clear Cutting ◽  
Partial Harvest ◽  
Forest Watersheds ◽  
Logging Impacts ◽  
Receiving Waters

Logging disturbances in boreal forest watersheds can alter biogeochemical processes in soils by changing forest composition, plant uptake rates, soil conditions, moisture and temperature regimes, soil microbial activity, and water fluxes. In general, these changes have often led to short-term increases in soil nutrient availability followed by increased mobility and losses by leaching to receiving waters. Among the studies we reviewed, dissolved organic carbon (DOC) exports usually increased after logging, and nitrogen (N) mineralization and nitrification often increased with resulting increased N availability and exports to receiving waters. Similar processes and responses occurred for phosphorus (P), but to a lesser extent than for N. In most cases, base cations were released and exported to receiving waters after logging. Several studies demonstrated that stem-only or partial-harvest logging reduced the impacts on nutrient release and exports in comparison to whole-tree clear-cutting. Despite these logging-induced increases in soil nutrient availability and movement to receiving waters, most studies reported little or no change in soil chemical properties. However, responses to logging were highly variable and often site specific. The likelihood, extent and magnitude of logging impacts on soil nutrient cycling and exports in boreal forest watersheds will be dependent on soil types, stand and site conditions, hydrological connectivity, post-logging weather patterns, and type and timing of harvest activities. Additionally, logging impacts can interact with, and be confounded by, atmospheric pollutant deposition and climate change. Further watershed-level empirical studies and modeling efforts are required to elucidate these interactions, to improve predictive capabilities, and to advance forest management guidelines for sustaining forest soil productivity and limiting nutrient exports.

scholarly journals Utikuma Region Study Area (URSA) – Part 1: Hydrogeological and ecohydrological studies (HEAD)

2016 ◽  
Vol 92 (01) ◽  
pp. 57-61 ◽  
Author(s):  
Kevin J. Devito ◽  
Carl Mendoza ◽  
Richard M. Petrone ◽  
Nick Kettridge ◽  
James M. Waddington
Keyword(s):  
Boreal Forest ◽  
Conceptual Understanding ◽  
Natural Disturbance ◽  
Spatially Explicit ◽  
Forest Research ◽  
Boreal Plains ◽  
Process Studies ◽  
Hydrogeological Studies ◽  
Western Boreal Forest

The Utikuma Region Study Area (URSA) was initiated to develop spatially explicit modelling tools to predict the cumulative impacts of land use and natural disturbance on the Boreal Plains (BP) ecozone of the Western Boreal Forest. Research comprised several multi-year projects, spanning wet and dry climate periods that combined intensive detailed process studies at seven watersheds with extensive long-term ecohydrological and hydrogeological studies conducted across a 60-km transect representing the range of glaciated landforms characteristic of the sub-humid boreal forest in Alberta. These studies have improved our conceptual understanding and capacity to numerically model how climate and geology influence water and energy flow, and the hydrologic linkages and natural variability of the key processes influencing BP ecosystems. Eco-hydrogeological frameworks have been developed for designing, conducting, interpreting, and extrapolating research results for watershed management and construction across the Boreal Plain ecozone.

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