Mortality of balsam fir and black spruce advance growth 3 years after clear-cutting

1995 ◽  
Vol 25 (9) ◽  
pp. 1528-1537 ◽  
Author(s):  
Jean-Claude Ruel ◽  
René Doucet ◽  
Jocelyn Boily
Keyword(s):  
Logistic Regression ◽  
Black Spruce ◽  
Height Growth ◽  
Seedling Quality ◽  
Balsam Fir ◽  
First Year ◽  
Logging Damage ◽  
Clear Cutting ◽  
Lean Angle ◽  
Logistic Regressions

The effects of balsam fir (Abiesbalsamea (L.) Mill.) and black spruce (Piceamariana (Mill.) B.S.P.) seedling attributes on survival were measured on four cutovers regenerated to black spruce and three regenerated to balsam fir. In each of these, about 240 stems were permanently identified shortly after logging and their main characteristics were noted. Survival was assessed after 1 and 3 years. First-year mortality reached 24% for balsam fir and and 21% for black spruce. It varied with height and seedling quality. Mortality during the second and third year after harvesting was less important and was more evenly distributed between the different height classes. When all height classes were combined, the logistic regression calculated for total balsam fir mortality was able to correctly classify the observations in 74% of the cases by using three variables: prerelease height growth, lean angle, and a wound index. For black spruce, seven variables were needed to correctly classify 78% of the observations. These were: height, prerelease height growth, live crown ratio, lean angle, distance to the straightening point, and two wound indices. Separate logistic regressions were calculated for stems smaller or taller than 30 cm. These regressions performed considerably better for the taller height class for both species. For balsam fir, lean angle and one or another wound index still remained in relation with survival. For black spruce, prerelease height growth and lean angle remained in relation with survival. Distance to the straightening point was only retained for stems below 30 cm while live crown ratio and the two wound indices were retained for stems over 30 cm. These results suggest that an evaluation of seedling quality using measures of previous suppression and logging damage should be introduced in regeneration surveys to better predict the evolution of a cutover after harvesting.

Effets de la coupe à blanc et de la coupe par bandes sur la régénération obtenue après 5 ans dans des pessières noires du Québec

1995 ◽  
Vol 25 (2) ◽  
pp. 329-342 ◽  
Author(s):  
Pierre Pominville ◽  
Jean-Claude Ruel
Keyword(s):  
Black Spruce ◽  
Spruce Budworm ◽  
Lower Proportion ◽  
The Other ◽  
Balsam Fir ◽  
Clear Cutting ◽  
Other Hand ◽  
The One ◽  
Almost All ◽  
Coupe À Blanc

An experiment was conducted to compare the effects of traditional clear-cutting with those of strip cutting on regeneration of black spruce, Piceamariana (Mill.) B.S.P., stands on scarified and unscarified uplands and on lowlands. To that effect, regeneration surveys were done before cutting, in the following year, and 3 and 5 years after cutting. Five years after harvesting, strip cutting led to higher coniferous stocking than clear-cutting on scarified uplands and on lowlands. On unscarified uplands, the gain attributable to strip cutting was not significant. The coniferous stocking of strip cuts on scarified uplands was not greater than on unscarified uplands. So the efficiency of scarification could not be proved in that study. Stocking obtained after 5 years remained closely related to the one observed immediately after harvesting in the strip cufs as in the clear-cuttings. This is particularly true for balsam fir, Abiesbalsamea (L.) Mill. In the strip cuts, the balsam fir stocking was constant while the one of black spruce increased. This could have an impact on the evolution of the composition of the new stands and, consequently, on their vulnerability to spruce budworm, Choristoneurafumiferana (Clem.). The majority of the clear-cuttings were well regenerated 5 years after harvesting. Their average coniferous stocking was slightly above 60%. However, 48% of the clear-cuttings did not reach this level when only unscarified plots on uplands were considered. Advance growth was abundant in those plots but suffered high losses during harvesting. Consequently, reducing the losses during harvesting would result in a lower proportion of clear-cuttings with insufficient coniferous stocking 5 years after cutting. On the other hand, almost all the strip cuts with insufficient regeneration after harvesting were well regenerated 5 years later. Thus, strip cutting could be an interesting option on sites with insufficient advance growth and on sites well regenerated before cutting but where important losses during harvesting are anticipated.

Potential use of bialaphos, a microbially produced phytotoxin, to control red raspberry in forest plantations and its effect on black spruce

1991 ◽  
Vol 21 (4) ◽  
pp. 489-497 ◽  
Author(s):  
Robert Jobidon
Keyword(s):  
Active Ingredient ◽  
Photosynthetically Active Radiation ◽  
Black Spruce ◽  
Growth Increment ◽  
Height Growth ◽  
First Year ◽  
Quadratic Relation ◽  
Foliar Injury ◽  
Red Raspberry ◽  
Active Radiation

Bialaphos foliar sprays were tested in eastern Quebec for control of red raspberry (Rubusidaeus L.), and the tolerance of planted black spruce (Piceamariana (Mill.) B.S.P.) seedlings was determined. Approximately 3 weeks after bialaphos was applied in July, August, or September, virtually all raspberry plants were killed. Efficiency of the June application, however, was much reduced. Spruce current-year foliage was more affected than older foliage. Foliar injury was more pronounced for bialaphos applications in June and July than for applications in August. First-year spruce survival was not affected by the treatments. Second-year evaluations revealed a significant quadratic relation of (i) month of application × bialaphos rate on raspberry density and (ii) bialaphos rate on raspberry height growth. Reduction in raspberry density and height growth was greater with the 2.0 and 2.5 kg active ingredient per hectare rates applied in August. As part of the evaluation of treatment efficiency, photosynthetically active radiation reaching spruce seedlings was measured using a portable integrating radiometer. Raspberry density and height growth were both negatively correlated with photosynthetically active radiation reaching spruce seedlings. A significant quadratic relation was found between bialaphos rate and 2nd-year spruce survival, which reached 95%, regardless of month and rate of application. A significant quadratic relation was found between spruce diameter growth increment and bialaphos rate. Except for calcium, 2nd-year spruce foliar mineral content was not affected by the treatments. Bialaphos treatments in August, with rates ranging from 1.0 to 2.0 kg active ingredient per hectare, had only slight or no adverse effects on spruce survival, foliar injury, and growth increment. Selective control of red raspberry in young black spruce plantations is a function of bialaphos rate and month of application.

GROWTH AND NUMBERS OF SPECKLED ALDER FOLLOWING LOGGING OF BLACK SPRUCE PEATLANDS

1964 ◽  
Vol 40 (4) ◽  
pp. 515-518 ◽  
Author(s):  
A. B. Vincent
Keyword(s):  
Black Spruce ◽  
Height Growth ◽  
Balsam Fir ◽  
Average Height ◽  
Northern Ontario ◽  
Crown Closure ◽  
Speckled Alder

Information collected on speckled alder during an examination of black spruce and balsam fir reproduction in peatlands of northern Ontario indicates that alder develops rapidly following cutting of the softwood overstorey, but the phase of most rapid height growth is completed within about 10 years when it has attained an average height of five to six feet. Openings of various sizes occur in alder stands. Exclusive of openings, the stands examined varied from 16,000 to 30,000 stems per acre, with the crown closure ranging from 40 to 80 per cent and averaging about 50 per cent.

Ten-year results of strip clear-cutting in Quebec black spruce stands

2000 ◽  
Vol 30 (1) ◽  
pp. 59-66 ◽  
Author(s):  
David Pothier
Keyword(s):  
Picea Mariana ◽  
Black Spruce ◽  
Height Growth ◽  
Clear Cutting ◽  
Advance Regeneration ◽  
Spruce Stands ◽  
Harvesting Method ◽  
Cost Efficient ◽  
One Year ◽  
Cutting System

Regeneration of first-cut strips in a two-cut system of strip clear-cutting was compared to that of large clear-cutting in four different areas representative of the black spruce (Picea mariana (Mill.) BSP) stands of the boreal forest of Quebec. Seedlings were more evenly distributed in clearcut strips than in large clearcuts. Differences of about 10 000 black spruce seedlings per hectare and 20% of stocking were observed in favour of clearcut strips compared to large clearcuts. Black spruce stocking was about 14% larger on lowland than on upland sites but height growth was better on upland sites. A regeneration problem similar to that of large clearcuts was observed when the second strips were cut. One year after cutting these second strips, winter harvesting resulted in a 23% gain in black spruce stocking as compared to summer harvesting. Even if black spruce stocking marginally increased during the years following winter harvesting, the height advantage of the preserved advance growth justifies the application of this harvesting method. The strip clear-cutting system effectively improved the stocking of former black spruce stands but if the stocking level of advance growth is adequate, careful harvesting to preserve advance regeneration should be the preferred method since it would be more cost-efficient.

Croissance en hauteur à long terme de la régénération préétablie dans des pessières noires boréales régénérées par marcottage, au Québec

1992 ◽  
Vol 22 (4) ◽  
pp. 613-621 ◽  
Author(s):  
Raynald Paquin ◽  
René Doucet
Keyword(s):  
Growth Rate ◽  
Black Spruce ◽  
Height Growth ◽  
Growth Patterns ◽  
Dominant Position ◽  
Clear Cutting ◽  
Effective Age ◽  
Second Growth ◽  
Spruce Stands ◽  
To Come

Height-growth patterns of black spruce (Piceamariana (Mill.) B.S.P.) in the boreal forest were studied in layer-origin stands released by clear-cutting in the first half of this century. Most stems responded to release brought about by clear-cutting of the main stand. Initially, small stems responded more rapidly and more strongly, but their height-growth rate culminated between 20 and 30 years following release, the same period when height-growth rate culminated for the taller, older stems. After the culmination period, growth rates were independent of height at the time of release. Consequently, the taller stems at time of release were able to maintain their dominant position. Height growth over the recent years indicates that this position could be maintained in the years to come, and even indefinitely. It seems that second-growth black spruce stands behave like even-aged stands despite their uneven-aged structure. Consequently, years since release and stem height are more accurate measures of stem effective age than total age. Moreover, the taller stems in the understory, which are usually considerably older, should be considered to be as valuable as smaller regeneration when a stand is cut.

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.

Croissance juvénile de marcottes d'épinette noire en régénération après récolte du couvert dominant

1993 ◽  
Vol 23 (7) ◽  
pp. 1396-1401 ◽  
Author(s):  
Jocelyn Boily ◽  
René Doucet
Keyword(s):  
Growth Rates ◽  
Natural Regeneration ◽  
Black Spruce ◽  
Height Growth ◽  
Management Unit ◽  
Site Quality ◽  
Clear Cutting ◽  
Ecological Regions ◽  
Spruce Stands ◽  
Stand Height

Annual height growth of natural regeneration was measured in 18- to 21-year-old clear-cuts of black spruce stands growing on sites of contrasted drainage, in two ecological regions of the Haute-Gatineau-et-Cabonga management unit in western Quebec. Most regeneration was established by layering and was growing slowly on all sites at time of release by clear-cutting of the main stand. Height growth rates increased rapidly thereafter on mesic sites: about 7 to 8 years after release, it reached 15 cm or more per year, and 32 to 45 cm per year 20 years after harvest. On moist sites, growth rates of 15 cm per year were attained only 10 to 15 years after release, and did not exceed 25 cm at age 20. These results show that growth of black spruce natural regeneration is controlled more by site quality than by the mechanism responsible for reproduction.

scholarly journals Factors associated with depressive episode among first year University students in Serbia

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
S Čanković ◽  
D Čanković ◽  
I Radić ◽  
D Rakić ◽  
S Ukropina ◽  
...  
Keyword(s):  
Mental Health ◽  
Logistic Regression ◽  
Depressive Symptoms ◽  
University Students ◽  
Depressive Episode ◽  
Social Health ◽  
Support Network ◽  
First Year ◽  
Behavioral Factors ◽  
First Year University

Abstract Background Some findings indicate that university students are at higher risk of depression despite being a socially advantaged population, showing that 15 to 25% of them develop some type of mental disorder during graduation, and depression is one of the most prevalent. The aim of this study was to investigate the prevalence of depressive symptoms and its association with gender, material status, social health, and behavioral factors among university students. Methods The research represents a cross-sectional study conducted at the University of Novi Sad, Serbia. The research involved 455 first-year students. The average age of participants was 19.3 years (72.1% girls and 27.9% boys). Patient Health Questionnaire (PHQ-9) was used to measure depressive symptoms (cut point for depressive episode ≥10). Additional questions were focused on self-assessed material status, social health, and behavioral factors (smoking and alcohol use). The binary logistic regression model was used to estimate the association between depression and observed independent variables. Results The prevalence of moderate to severe depressive episode among students was 18.0%, with no gender differences. Out of the total, 11.0% of students had suicidal thoughts or thoughts of hurting themselves. Multivariable logistic regression showed that self-assessed poor material status (OR = 2.04; 95%CI: 1.06-3.89), self-assessed poor social health (OR = 8.9; 95%CI:4.87-16.42) and smoking (OR = 2.18; 95%CI: 1.09-4.39) were significant predictors of depression among first-year university students. Conclusions High prevalence of depressive episode among university students call for the action for the promotion of mental health, particularly among those of lower socioeconomic status, and points out the importance of social health and social network in the prevention of mental disorders. Key messages Students on the first year of University should be screened for depressive symptoms. It is important to educate students on how to create a strong support network and to implement intervention programs for improving mental health through fostering healthy lifestyles change.

Direct seeding of black spruce in northwestern Ontario: Seedbed relationships

1994 ◽  
Vol 70 (2) ◽  
pp. 151-158 ◽  
Author(s):  
R. L. Fleming ◽  
D. S. Mossa
Keyword(s):  
Seedling Establishment ◽  
Black Spruce ◽  
Mineral Soil ◽  
Soil Surface ◽  
Direct Seeding ◽  
First Year ◽  
Strongly Correlated ◽  
Seedling Mortality ◽  
Northwestern Ontario ◽  
Seedbed Preparation

A series of spot seeding experiments was set out on coarse-textured upland sites in northwestern Ontario to investigate how black spruce (Picea mariana [Mill.] B.S.P.) seedling establishment and growth could be improved by site selection and seedbed preparation. Virtually all germination occurred within the first growing season. Annual seedling mortality rates were greatest during the first year, then declined steadily and stabilized at low levels (<10%) after the third year. The highest fifth-year establishment ratios (seedlings/viable seed sown) were found on seedbeds derived from materials near the mineral soil/humus interface. On wetter sites (i.e., higher Soil Moisture Regimes) the best seedbeds occurred closer to the soil surface. Mean fifth year establishment ratios for the best seedbeds were 0.032 on moderately fresh to fresh sites, 0.146 on very fresh to moderately moist sites, and 0.082 on moist to very moist sites. On adjacent lowland sites, slow-growing, compact Sphagnum mosses had a mean establishment ratio of 0.179. Mean fifth-year seedling heights on upland sites ranged from 12 to 14 cm, and were not strongly correlated with site or seedbed type. Key words: direct seeding, black spruce, seedbed, seedling establishment, site type and germination

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