The relationship between site and tree characteristics and the presence of wet heartwood in black spruce in the boreal forest of Quebec, Canada

2006 ◽  
Vol 36 (6) ◽  
pp. 1519-1526 ◽  
Author(s):  
Cornelia Krause ◽  
Réjean Gagnon
Keyword(s):  
Boreal Forest ◽  
Black Spruce ◽  
Significant Proportion ◽  
Organic Soil ◽  
Average Height ◽  
Groundwater Levels ◽  
Site Characteristics ◽  
Content Classification ◽  
Study Sites ◽  
The Relationship

Wet heartwood in black spruce (Picea mariana (Mill.) BSP) causes considerable problems during the drying process. Forest companies try to avoid harvesting stands with wet heartwood, but no relationship has been yet established between the incidence of wet heartwood and tree or site characteristics. To characterize areas containing a significant proportion of black spruce affected by wet heartwood, a total of 635 black spruce trees were sampled in eighteen 400 m2 study plots under management in the central boreal forest of Quebec. A total of 18 study sites were analysed and classified as wet, intermediate, or dry, based on the proportion of individuals with wet heartwood. Thirteen of the study sites were classified as wet, two as intermediate, and three as dry. The average age calculated for trees on wet sites was significantly (p = 0.0001) higher than that of the other two classes, whereas growth rate was significantly lower on wet sites. No difference was noted in the average height or diameter of the individuals from all three classes. The wet sites contained organic soil, whereas Podzols characterized two of the three dry study sites. An additional sampling of black spruce (n = 509) revealed a significant relationship between the groundwater level and heartwood moisture content classification (i.e., dry, intermediate, or wet). Trees in the dry heartwood class grew on sites with the lowest groundwater levels (p = 0.002) compared with trees in the wet or intermediate classes.

Landscape-level variability in the age underestimation of understory black spruce in the northern boreal forest of Quebec

2005 ◽  
Vol 35 (3) ◽  
pp. 633-642 ◽  
Author(s):  
Marc-André Parisien ◽  
Luc Sirois ◽  
Sylvain Parent
Keyword(s):  
Boreal Forest ◽  
Mixed Models ◽  
Black Spruce ◽  
Ground Level ◽  
Simple Linear Regression ◽  
Linear Regression Models ◽  
Growth Rings ◽  
Age Correction ◽  
The Relationship ◽  
Landscape Level

This study examines the variability of the potential aging error for saplings (height ≤1.5 m) of black spruce (Picea mariana (Mill.) B.S.P.) in mature fire-dominated stands (n = 14 stands) of the northern boreal forest of northwestern Quebec. Age underestimation was determined by counting the number of underground bud scars of saplings. The magnitude and variability of age underestimation was compared within and among stands. The relationship between corrected ages (the sum of age underestimation and the number of growth rings at ground level) and ground-level ages was strongly linear and was therefore described with simple linear regression models. To evaluate landscape-level variability in this relationship, the regressions were compared among stands using mixed models. Despite high variability in age underestimation at the stand level, the relationship between corrected and ground-level age was highly significant (p < 0.0001) for all stands except one. However, there were many significant statistical differences between these regressions, indicating high landscape-level variability. The magnitude of age underestimation was found to be highly site specific (means of 7–26 years), the phenomenon being more marked and variable in older stands. Given high landscape-level variability, age underestimation of understory black spruce saplings in northern boreal stands must be documented for every sampled stand to apply a valid age correction in studies that involve multiple stands.

Postfire dynamics of black spruce coarse woody debris in northern boreal forest of Quebec

2006 ◽  
Vol 36 (7) ◽  
pp. 1770-1780 ◽  
Author(s):  
Yan Boulanger ◽  
Luc Sirois
Keyword(s):  
Moisture Content ◽  
Boreal Forest ◽  
Nitrogen Content ◽  
Decomposition Rate ◽  
Coarse Woody Debris ◽  
Black Spruce ◽  
Woody Debris ◽  
Decomposition Rates ◽  
Asymbiotic Nitrogen Fixation ◽  
Study Sites

In this study, postfire coarse woody debris (CWD) dynamics in northern Quebec, Canada, were assessed using a 29-year chronosequence. Postfire woody-debris storage, decomposition rates, and variation of nitrogen and carbon contents of black spruce CWD (Picea mariana (Mill.) BSP) are estimated. The decomposition rate for postfire snags is exceptionally slow (k = 0.00), while the decomposition rate for logs (k = 0.019–0.021) is within previously recorded values for the boreal forest. The low decomposition rate for snags could be related to low moisture content associated with the position of debris and fast bark shedding. Given the low CWD decomposition rates and CWD storage (21.3–66.8 m3·ha–1), carbon losses from postfire CWD are relatively low, varying between 35.5 and 128.8 kg·ha–1·year–1 at the study sites. The nitrogen content in CWD drops quickly between living trees and snags and increases slightly with time since fire in logs. Nitrogen content is not related to wood density or to moisture content of deadwood. Rapid loss of nitrogen is associated with fast decomposition of subcortical tissues, leaching, and insect comminution. The increase in nitrogen content at the oldest site could result from asymbiotic nitrogen fixation, although a longer time span in the chronosequence would probably have revealed a greater nitrogen gain in increasingly decayed CWD.

Thinking and acting differently for sustainable management of the boreal forest

1999 ◽  
Vol 75 (6) ◽  
pp. 929-938 ◽  
Author(s):  
Christian Messier ◽  
Daniel D. Kneeshaw
Keyword(s):  
Forest Management ◽  
Boreal Forest ◽  
Ecosystem Management ◽  
Sustainable Management ◽  
Sustainable Forest Management ◽  
Black Spruce ◽  
Significant Proportion ◽  
Crop Species ◽  
Forestry Practices ◽  
The Impact

Sustainable forest management has replaced sustained yield as the new management strategy for most countries and forest companies. This concept has generated a lot of interest and discussion, and a great deal of effort is being made to modify current forestry practices to be sustainable. In this paper, we argue that the still somewhat vague concept of sustainable forest management calls for a substantial modification in our way of thinking about and practising forestry. To move toward that goal, we recognize important social and economic challenges to sustainable management and suggest nine essential notions: 1) manage the forest ecosystem as a whole and not in parts nor only for the crop species; 2) conserve a significant proportion of the boreal forest (i.e., at least 12%); 3) practice intensive forestry on a small portion of the land to recover the fibre lost from notions 1 and 2; 4) strive for innovation in thinking and acting; 5) foster research and development to support notion 4; 6) balance regional needs with that of the global community; 7) encourage public participation; 8) consider the impact of substantial change in climate over the next 100 years (or next rotation); and 9) substitute regulations that are adaptive for those that are restrictive. An example of the kind of silviculture that could be used in ecosystem management for the black spruce forest is also discussed. Key words: sustainability, ecosystem management, boreal forest, socio-economic and biophysical concerns, natural dynamics

Spatiotemporal variation in black spruce cone and seed crops along a boreal forest - tree line transect

2000 ◽  
Vol 30 (6) ◽  
pp. 900-909 ◽  
Author(s):  
Luc Sirois
Keyword(s):  
Boreal Forest ◽  
Black Spruce ◽  
Forest Tree ◽  
Line Transect ◽  
Tree Line ◽  
Cone Production ◽  
Forest Sites ◽  
Seed Crops ◽  
The Relationship ◽  
Filled Seeds

To assess the relationship between the regenerative potential of black spruce (Picea mariana (Mill.) BSP) and the latitudinal and thermal gradients, the cone crop was monitored in the same selection of trees during the 1989-1995 period in the northern boreal forest (sites A, n = 49, and B, n = 48), in the southern forest-tundra transition zone (site C, n = 35), and at the tree line (site D, n = 21). The size of the cone crop, the amount of seeds extracted per cone, along with the percentages of filled seed and germination were measured on each tree. There was no south to north trend associated with the cone crop. The cone crop at tree line was not significantly lower than in either of the southerly sites in six of the seven observed years. The number of seeds extracted per cone, the percentage of filled seeds, and the germination of filled seeds showed significant decrease northward according to year. Although there was no significant relationship between temperature and the cone production over the study area, the percentages of filled seeds and germination were significantly (0.51 [Formula: see text] r2 [Formula: see text] 0.44; p < 0.001) associated with the regional variation in heat sum.

scholarly journals Snag use by Foraging Black-Backed Woodpeckers (Picoides Arcticus) in a Recently Burned Eastern Boreal Forest

The Auk ◽  
2003 ◽  
Vol 120 (2) ◽  
pp. 505-511 ◽  
Author(s):  
Antoine Nappi ◽  
Pierre Drapeau ◽  
Jean-François Giroux ◽  
Jean-Pierre L. Savard
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Black Spruce ◽  
High Quality ◽  
Salvage Logging ◽  
Northeastern North America ◽  
Picoides Arcticus ◽  
One Year ◽  
The Relationship ◽  
Wood Boring

Abstract We studied snag use for foraging by Black-backed Woodpeckers (Picoides arcticus) one year after a fire in an eastern black spruce (Picea mariana) boreal forest in Quebec, Canada. We searched for signs of foraging (bark flaking and excavation holes) by Black-backed Woodpeckers on 6,536 snags sampled in 56 plots located in portions of the burned forest that had not been salvage logged. A logistic regression model was developed based on the presence or absence of foraging signs. Results showed that Black-backed Woodpeckers used larger snags that were less deteriorated by fire (qualified as high-quality snags). Direct field observations of individuals foraging on 119 snags also indicated that used snags corresponded to those of high predicted quality. Finally, we assessed the relationship between food availability and snag characteristics by measuring the density of wood-boring beetle larvae holes on 30 snags of different size and deterioration classes. High-quality snags contained higher prey densities (wood-boring beetle holes) than smaller and more deteriorated snags. We recommend that forest blocks characterized by large and less deteriorated trees be preserved from salvage logging in recently burned boreal forests in northeastern North America.

scholarly journals Success Factors for Experimental Partial Harvesting in Unmanaged Boreal Forest: 10-Year Stand Yield Results

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1199
Author(s):  
Louiza Moussaoui ◽  
Alain Leduc ◽  
Miguel Montoro Girona ◽  
Annie Claude Bélisle ◽  
Benoit Lafleur ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Tree Mortality ◽  
Stand Structure ◽  
Black Spruce ◽  
Organic Layer ◽  
Stand Development ◽  
Partial Harvesting ◽  
Site Characteristics ◽  
Spruce Stands ◽  
Stand Yield

Over the past two decades, partial harvesting has been increasingly used in boreal forests as an alternative to clearcutting to promote irregular stand structures and maintain a balance between biodiversity preservation and continued timber production. However, relatively little is still known about the silvicultural potential of partial harvesting in Canada’s boreal forest, especially in areas prone to organic matter accumulation (paludification), and most prior research has focused on biodiversity responses. In this study, we assess the effects of partial harvesting on stand development (recruitment, growth, and mortality) ten years after harvesting in previously unmanaged black spruce stands and quantify its effectiveness in reducing the impacts on ecosystem structures. Our analyses revealed that pre-harvest stand structure and site characteristics, especially initial basal area, sapling density, tree diameter, and organic layer thickness (OLT) were major factors involved in stand development ten years following these partial harvesting treatments. Depending on pre-harvest structure and site characteristics, partial harvesting can result in either an increase in post-harvest tree recruitment and growth or a loss of stand volume because of standing tree mortality. To increase the chances of partial harvesting success in ensuring an increase in decennial stand yield after harvest in black spruce forest stands, sites prone to paludification (i.e., where OLT >17 cm) should be left unharvested. This study illustrates the importance of taking into account pre-existing structure and site characteristics in the selection of management strategies to maximize the potential of partial harvesting to achieve sustainable forest management in black spruce stands.

In Search of the Prosocial Personality

2019 ◽  
Vol 40 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Anja Wertag ◽  
Denis Bratko
Keyword(s):  
Prosocial Behavior ◽  
Personality Traits ◽  
Significant Proportion ◽  
Dark Triad ◽  
Self Report ◽  
Hierarchical Regression ◽  
Regression Analyses ◽  
The Relationship

Abstract. Prosocial behavior is intended to benefit others rather than oneself and is positively linked to personality traits such as Agreeableness and Honesty-Humility, and usually negatively to the Dark Triad traits (i.e., Machiavellianism, narcissism, and psychopathy). However, a significant proportion of the research in this area is conducted solely on self-report measures of prosocial behavior. Therefore, the aim of this study was to investigate the relationship between prosociality and the basic (i.e., HEXACO) and dark personality traits, comparing their contribution in predicting both self-reported prosociality and prosocial behavior. Results of the hierarchical regression analyses showed that the Dark Triad traits explain prosociality and prosocial behavior above and beyond the HEXACO traits, emphasizing the importance of the Dark Triad in the personality space.

scholarly journals Assessing Wildfire Burn Severity and Its Relationship with Environmental Factors: A Case Study in Interior Alaska Boreal Forest

2021 ◽  
Vol 13 (10) ◽  
pp. 1966
Author(s):  
Christopher W Smith ◽  
Santosh K Panda ◽  
Uma S Bhatt ◽  
Franz J Meyer ◽  
Anushree Badola ◽  
...  
Keyword(s):  
Boreal Forest ◽  
Ground Truth ◽  
Burn Severity ◽  
Classification Methods ◽  
Spectral Indices ◽  
Ground Truth Data ◽  
Burn Scar ◽  
Interior Alaska ◽  
Remote Sensing Methods ◽  
The Relationship

In recent years, there have been rapid improvements in both remote sensing methods and satellite image availability that have the potential to massively improve burn severity assessments of the Alaskan boreal forest. In this study, we utilized recent pre- and post-fire Sentinel-2 satellite imagery of the 2019 Nugget Creek and Shovel Creek burn scars located in Interior Alaska to both assess burn severity across the burn scars and test the effectiveness of several remote sensing methods for generating accurate map products: Normalized Difference Vegetation Index (NDVI), Normalized Burn Ratio (NBR), and Random Forest (RF) and Support Vector Machine (SVM) supervised classification. We used 52 Composite Burn Index (CBI) plots from the Shovel Creek burn scar and 28 from the Nugget Creek burn scar for training classifiers and product validation. For the Shovel Creek burn scar, the RF and SVM machine learning (ML) classification methods outperformed the traditional spectral indices that use linear regression to separate burn severity classes (RF and SVM accuracy, 83.33%, versus NBR accuracy, 73.08%). However, for the Nugget Creek burn scar, the NDVI product (accuracy: 96%) outperformed the other indices and ML classifiers. In this study, we demonstrated that when sufficient ground truth data is available, the ML classifiers can be very effective for reliable mapping of burn severity in the Alaskan boreal forest. Since the performance of ML classifiers are dependent on the quantity of ground truth data, when sufficient ground truth data is available, the ML classification methods would be better at assessing burn severity, whereas with limited ground truth data the traditional spectral indices would be better suited. We also looked at the relationship between burn severity, fuel type, and topography (aspect and slope) and found that the relationship is site-dependent.

The Relationship Between Frictional Resistance and Roughness for Surfaces Smoothed by Sanding

2002 ◽  
Vol 124 (2) ◽  
pp. 492-499 ◽  
Author(s):  
Michael P. Schultz
Keyword(s):  
Reynolds Number ◽  
Frictional Resistance ◽  
Resistance Coefficient ◽  
Polished Surface ◽  
Average Height ◽  
Freestream Velocity ◽  
Number Range ◽  
Test Fixture ◽  
Plate Length ◽  
The Relationship

An experimental investigation has been carried out to document and relate the frictional resistance and roughness texture of painted surfaces smoothed by sanding. Hydrodynamic tests were carried out in a towing tank using a flat plate test fixture towed at a Reynolds number ReL range of 2.8×106−5.5×106 based on the plate length and freestream velocity. Results indicate an increase in frictional resistance coefficient CF of up to 7.3% for an unsanded, as-sprayed paint surface compared to a sanded, polished surface. Significant increases in CF were also noted on surfaces sanded with sandpaper as fine as 600-grit as compared to the polished surface. The results show that, for the present surfaces, the centerline average height Ra is sufficient to explain a large majority of the variance in the roughness function ΔU+ in this Reynolds number range.

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