Abondance de la régénération 5 ans après la coupe à blanc mécanisée de peuplements d'épinette noire (Piceamariana)

1992 ◽  
Vol 22 (11) ◽  
pp. 1630-1638 ◽  
Author(s):  
Jean-Claude Ruel

Regeneration was studied 5 years after harvesting on 128 permanent blocks located before logging in black spruce (Piceamariana (Mill.) BSP) stands. Regeneration after 5 years was related to the abundance of advance growth, mainly black spruce layers. Regeneration also differed with the harvesting system used. Best results were obtained with the use of feller-forwarders while tree-length harversting gave the lowest softwood stockings. Regional climax and soil texture also had an effect, mostly by modifying the advance growth abundance. The better softwood stocking observed on thick humus and in the black spruce -moss climax zone was related to higher precutting regeneration levels. The regeneration problems observed on coarse textured soils were also associated with initial differences in the amount of advance growth. The duration of spruce budworm (Choristoneurafumiferana (Clem.)) infestations seemed to have an impact on the regeneration of the stands studied. Hardwoods regeneration, mostly white birch (Betulapapyrifera (Marsh.)), became established after logging or after defoliation by the spruce budworm. Their abundance was also dependent on regional climax and soil texture.

1995 ◽  
Vol 25 (2) ◽  
pp. 329-342 ◽  
Author(s):  
Pierre Pominville ◽  
Jean-Claude Ruel

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.


1977 ◽  
Vol 7 (4) ◽  
pp. 648-655 ◽  
Author(s):  
Gilles Frisque ◽  
P. E. Vézina

Small clear-cuttings (elliptical, circular, and strip) were made in the commercial boreal forest in Quebec to improve black spruce (Piceamariana (Mill.) B.S.P.) reproduction.Five years after cutting, black spruce layers were as numerous as black spruce seedlings and total softwood reproduction averaged 26 710 stems per hectare (10 810 stems per acre) with 90% stocking. In some cases, white birch stems tripled between the 1st and 5th year after cutting, which may have an important effect on stand composition.Strip cuts gave more stems per hectare than circular or elliptical cuts but stocking was lower. Strips 40 m wide (130 ft) gave better results than those 80 m wide (260 ft).Stocking, although adequate in all these small clear-cuttings, appears to be a more critical factor in the success of softwood reproduction than is density.


1983 ◽  
Vol 13 (6) ◽  
pp. 1030-1036 ◽  
Author(s):  
G. F. Weetman ◽  
D. Algar

An old, merchantable, low-site class black spruce (Piceamariana (Mill.) B.S.P.) stand growing on a Lithic Humo-Ferric Podzol overlying a granite bedrock, and a younger but merchantable low-site class jack pine (Pinusbanksiana Lamb.) stand growing on a Ferro-Humic Podzol overlying a deep coarse sand near Baie Comeau, P.Q., were analysed for stand biomass and macronutrient contents of both stand and soil. The magnitude of the depletions of macronutrients from the site, in full-tree and tree-length methods of logging, are compared with their available and total quantities in the soil. The range of values from the literature for nutrient inputs are presented and discussed in relation to logging losses. The results suggest that full-tree logging in the dry jack pine stand could cause a severe loss of potentially mineralizable N supply; P, K, and Mg deficiency problems owing to export are not apparent, but a Ca balance problem is apparent. The implication is that full-tree logging should be avoided on such sites.


2011 ◽  
Vol 87 (05) ◽  
pp. 612-624 ◽  
Author(s):  
Eric Alvarez ◽  
Louis Bélanger ◽  
Louis Archambault ◽  
Frédéric Raulier

Pre-industrial forest cover portrait is a recognized method for establishing the bases of sustainable forest management. However, it is a spatially and temporally dependant concept that should be used with caution in presence of big fires. The objective of the study was to portray the pre-industrial landscape in a mixedwood temperate forest in central Quebec at different spatial scales. The study was based on archival records from a forest company. The pre-industrial forest cover landscape of our study area was mainly composed of mature or old-growth (>100 years) stands and dominated by mixedwood forest stands with intolerant hardwoods. The main tree species were white birch, black spruce and jack pine, three species associated to forest succession after fire in the boreal forest. Considering the great variability caused by the fires and partial knowledge of this variability, for each spatial scale considered, we propose some management targets based on the main pre-industrial characteristics of this forest. To respect the pre-industrial variability, our study suggested that silviculture should be adapted at different landscape scales. Cover types and age class targets should be based on main preindustrial characteristics at each landscape scale analyzed.


1997 ◽  
Vol 14 (1) ◽  
pp. 40-43 ◽  
Author(s):  
Barry C. Kostyk ◽  
Kevin W. Wanner

Abstract A neem seed extract was applied to black spruce trees at two stages of reproductive development to control insect damage to the seed cones. Applied after pollination, neem had no effect on damage by the spruce cone maggot but did provide some protection against defoliation by the spruce budworm. Neem had no effect on the numbers of spruce budworm larvae for the first 9 days of the experiment, but after 23 days, populations declined on trees with two of three neem treatments compared to control trees. Neem reduced cone grazing damage by lepidopteran larvae when applied during the flowering stage. However, increased female flower abortion also resulted. The application of neem seed extract for controlling spruce budworm damage appears promising, but more information is needed on earlier applications in the field to determine if this product could be used operationally without causing substantial flower abortion. North. J. Appl. For. 14(1):40-43.


1998 ◽  
Vol 15 (3) ◽  
pp. 135-140 ◽  
Author(s):  
David A. MacLean ◽  
Wayne E. MacKinnon

Abstract Data from the assessment of current defoliation levels on 172,000 individual shoots from 6890 midcrown branches sampled from balsam fir and spruce stands were used to define sampling protocols for assessing defoliation caused by spruce budworm. The method was based on sampling one midcrown branch from each of x host trees per stand, and assessing defoliation of y individual shoots per branch. Both the number of shoots per branch and the number of branches required per stand varied with host species (balsam fir, white spruce, or red-black spruce) and with average defoliation level. Sample sizes required to estimate mean defoliation with 90% confidence that the confidence interval is ±10% ranged from 7 to 24 branches per stand and from 17 to 58 shoots per branch, with the largest samples required at moderate (31-70%) defoliation levels. Estimated costs of shoot and branch sampling and processing ranged from $40-110/stand, based on a 90% confidence level salary rate of $12(Can.)/hr, and excluding travel costs. Results can be applied using a preliminary assessment to determine the general defoliation level, which along with species, determines the required sample size. North. J. Appl. For. 15(3):135-140.


1985 ◽  
Vol 117 (4) ◽  
pp. 395-399 ◽  
Author(s):  
Daniel J. Robison ◽  
Lawrence P. Abrahamson ◽  
Miroslaw M. Czapowskyj ◽  
Edwin H. White ◽  
Douglas C. Allen

AbstractOptimum size of a sample unit and within-branch distribution of overwintering spruce budworm were determined for black spruce in northern Maine. No significant differences in sample reliability were found between whole-branch and 45-cm branch-tip samples. Larval distribution on branches varied with total branch length and a model was developed to estimate the whole-branch population from a 45-cm branch tip. Use of a 45-cm branch-tip sample unit is recommended because it is biologically and statistically valid and reduces sampling costs.


2018 ◽  
Vol 430 ◽  
pp. 421-430 ◽  
Author(s):  
Anne Cotton-Gagnon ◽  
Martin Simard ◽  
Louis De Grandpré ◽  
Daniel Kneeshaw

2001 ◽  
Vol 31 (12) ◽  
pp. 2160-2172 ◽  
Author(s):  
Martin Simard ◽  
Serge Payette

Black spruce (Picea mariana (Mill.) BSP) is the dominant tree species of the southernmost (48°N) lichen woodlands in eastern Canada. Most spruce trees in mature lichen woodlands appear to be declining, as shown by the massive invasion of the epiphytic lichen Bryoria on dead branches of dying trees. A dendroecological study was undertaken to identify the main causal factors of the decline. A decline index based on the abundance of Bryoria on spruce trees was used to distinguish healthy from damaged lichen–spruce woodlands and to select sampling sites for tree-ring measurements. Three conifer species (black spruce, balsam fir (Abies balsamea (L.) Mill.), and jack pine (Pinus banksiana Lamb.)) were sampled to compare their growth patterns in time and space. In the late 1970s and mid-1980s, black spruce and balsam fir experienced sharp and synchronous radial-growth reductions, a high frequency of incomplete and missing rings, and mass mortality likely caused by spruce budworm (Choristoneura fumiferana (Clem.)) defoliation. Jack pine, a non-host species, showed no such trend. Because black spruce layers were spared, lichen woodlands will eventually regenerate unless fire occurs in the following years. Black spruce decline can thus be considered as a normal stage in the natural dynamics of the southern lichen woodlands.


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