Mortality in black spruce stands of fire or clear-cut origin

2002 ◽  
Vol 32 (3) ◽  
pp. 539-547 ◽  
Author(s):  
Jean-Martin Lussier ◽  
Hubert Morin ◽  
Réjean Gagnon

The mortality pattern of 14 black spruce (Picea mariana (Mill.) BSP) stands from the Saguenay region (Quebec), originating from fire or clear-cutting in the early 20th century, was reconstructed based on the dendrochronological dating of dead trees. Most of the spruces died during the 1970s and 1980s, which suggests the possible impact of the most recent spruce budworm (Choristoneura fumiferana Clem.) outbreak. This hypothesis is supported by the observation of major growth reductions synchronous with known outbreak periods and by the existence of a significant partial correlation between the mortality rates and the occurrence of outbreaks. A significant partial correlation between the mortality rates and the relative density of the studied stands suggests that competition amongst individuals might act as a predisposing factor to the death of trees, while the outbreaks act as an inciting factor. The observed mortality pattern is similar to self-thinning, since most of the dead trees were from the smallest size classes.

1954 ◽  
Vol 30 (4) ◽  
pp. 372-379 ◽  
Author(s):  
Henri LeBlanc

Lack of reproduction of black spruce, Picea mariana, in pure black spruce stands in old cut-over areas, has always been a great subject of discussion and one for intensive work among foresters. Many reasons such as the absence of an adequate seed supply stored on top of humus, or adverse germination conditions are said to be partly responsible.This study on the humus of this unregenerated cut-over area, indicates clear cutting of this stand will influence the normal concentration of definite micro-nutrients such as manganese and magnesium.The augmentation of manganese in the soil has a detrimental effect on the growth of plants when, its concentration is too high. The diminution of magnesium, which is an element necessary to stimulate the growth, must create abnormal nutritive conditions of the habitat. This visible lack of equilibrium might be the cause of the absence of seedlings of Picea mariana on certain parts of this cut-over area.


2002 ◽  
Vol 32 (2) ◽  
pp. 283-294 ◽  
Author(s):  
R D Whitney ◽  
R L Fleming ◽  
K Zhou ◽  
D S Mossa

Root and butt rots are often implicated as causal factors influencing windfall and mortality of residual trees following partial cutting. Measurements of decay at stump level (i.e., the upward extension of root rot) were made on cross-sectional discs taken from windfallen and standing dead 100- to 130-year-old black spruce (Picea mariana (Mill.) BSP) near Nipigon in northwestern Ontario. Subsequently, causal fungi were identified using laboratory culturing procedures. The incidence and amount of decay in windfallen trees within leave strips following alternate strip clear-cutting was higher than the general stand levels but lower than that found in windfallen trees in uncut forest. The incidence and amount of decay was also higher in windfallen trees near the centres of the leave strips than in those near the edges and corners of these strips. These results indicate a strong association between root rot and windfall and suggest that for comparable windfirmness, trees near the edges of residual stands must have less decay than those in more sheltered locations. Decay levels tended to be lower on poorly drained sites than on well-drained sites. In uncut forest, and especially in the leave strips, more trees were uprooted than died standing or suffered stem breakage. The incidence and amount of decay tended to be lower in uprooted trees than in standing dead trees or those with stem breakage, although in uncut forest virtually all windfallen or standing dead trees had some degree of stump-level decay. Of the 21 wood-rotting Basidiomycetes isolated from windfallen and standing dead trees, Inonotus tomentosus (Fr.:Fr.) Teng was the most frequent, followed in order by Armillaria ostoyae (Romagn.) Herink, Coniophora puteana (Schum.:Fr.) Karst., and Scytinostroma galactinum (Fr.) Donk. The incidence of I. tomentosus, C. puteana, Xeromphalina campanella (Batsch.:Fr.) Kuhner & Maire, and Serpula himantioides (Fr.:Fr.) Karst., but not Armillaria ostoyae, Scytinostroma galactinum, and Sistotrema brinkmanii (Bres.) Erik., was greater in windfallen and standing dead trees from the leave strips than in the general stand populations. In the leave strips, I. tomentosus, Amylostereum chailletii (Pers.:Fr.) Boid., and Trichaptum abietinum (Dickson:Fr.) Ryv. tended to greater relative abundance in standing dead trees, while the relative abundance of C. puteana and Serpula himantioides was greater in trees with stem breakage. Armillaria ostoyae and Scytinostroma galactinum were as abundant in uprooted trees as in standing dead trees or those with stem breakage. Ascocoryne sarcoides (Jacq.:Fr.) G. & W., a staining fungus that may protect against decay fungi, was frequently isolated in this study.


2000 ◽  
Vol 30 (1) ◽  
pp. 59-66 ◽  
Author(s):  
David Pothier

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.


Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 850 ◽  
Author(s):  
Janie Lavoie ◽  
Miguel Montoro Girona ◽  
Hubert Morin

Spruce budworm (Choristoneura fumiferana) is the main defoliator of conifer trees in North American boreal forests, affecting extensive areas and causing marked losses of timber supplies. In 2017, spruce budworm affected more than 7 million ha of Eastern Canadian forest. Defoliation was particularly severe for black spruce (Picea mariana (Mill.) B.S.P.), one of the most important commercial trees in Canada. During the last decades, intensive forest exploitation practices have created vast stands of young balsam fir (Abies balsamea (L.) Mill.) and black spruce. Most research focused on the impacts of spruce budworm has been on mature stands; its effects on regeneration, however, have been neglected. This study evaluates the impacts of spruce budworm on the defoliation of conifer seedlings (black spruce and balsam fir) in clearcuts. We measured the cumulative and annual defoliation of seedlings within six clearcut black spruce stands in Quebec (Canada) that had experienced severe levels of defoliation due to spruce budworm. For all sampled seedlings, we recorded tree species, height class, and distance to the residual forest. Seedling height and species strongly influenced defoliation level. Small seedlings were less affected by spruce budworm activity. As well, cumulative defoliation for balsam fir was double that of black spruce (21% and 9%, respectively). Distance to residual stands had no significant effect on seedling defoliation. As insect outbreaks in boreal forests are expected to become more severe and frequent in the near future, our results are important for adapting forest management strategies to insect outbreaks in a context of climate change.


1992 ◽  
Vol 22 (4) ◽  
pp. 613-621 ◽  
Author(s):  
Raynald Paquin ◽  
René Doucet

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.


1999 ◽  
Vol 77 (12) ◽  
pp. 1850-1860 ◽  
Author(s):  
Louis Imbeau ◽  
Jean-Pierre L Savard ◽  
Réjean Gagnon

Comparisons of the effects of logging and fire as disturbance agents on the composition of bird assemblages in boreal ecosystems are still lacking or are limited to the short-term impacts of clear-cutting. In Quebec, where the boreal forest is largely dominated by black spruce (Picea mariana (Mill.) B.S.P.) stands, we surveyed 140 point-count stations in 3 postlogging and 4 postfire development stages determined according to the height of the regenerating spruce trees. Species richness did not vary among forest development stages, but bird abundance was higher in recent clearcuts. Recently disturbed areas were characterized by open-land bird assemblages dominated by Neotropical migrants, which reached their highest abundance in clearcuts. Moreover, logged stands were distinguished from burned sites by the absence of cavity-nesting birds. Forest-bird assemblages reestablished themselves as soon as young spruces reached the sapling stage. However, the Black-backed Woodpecker (Picoides arcticus), Three-toed Woodpecker (Picoides tridactylus), and Brown Creeper (Certhia americana) were restricted to mature stands or recent burns and are thus likely to be negatively affected by modern forestry, which involves fire suppression and short logging rotations. We suggest that retention of larger areas of continuous mature forest might be essential to maintain these species in managed regions.


1995 ◽  
Vol 25 (4) ◽  
pp. 536-544 ◽  
Author(s):  
David Pothier ◽  
René Doucet ◽  
Jocelyn Boily

The advance regeneration often present following clear-cutting in black spruce (Piceamariana (Mill.) B.S.P.) stands is generally composed of individuals of various heights. This initial height difference is hypothesized to affect the yield of the future stand. Height of the advance regeneration at time of release was determined on several black spruce trees within 33 stands distributed across the boreal forest of the province of Quebec, Canada. From these data, a regeneration structure index was developed and used to explain a part of the variation in subsequent stand yield. Dominant trees of stands developing for 38 to 65 years since clear-cutting generally originated from the tallest advance regeneration at time of release. Stands with the tallest regeneration at time of release produced the largest yields for a given site quality and number of years since harvesting. A 3-m increase in advance-regeneration height resulted in a similar yield gain as a 3-m increase in site index. Site indices calculated from age-height relationships of dominant trees originating from tall advance regeneration were less than those calculated from trees that have undergone a relatively short period of suppression. These results suggest that traditional management tools developed for fire-origin black spruce stands, i.e., stands mainly composed of seed-origin trees established after perturbation, should be adjusted for clearcut-origin stands that largely develop from advance regeneration.


1993 ◽  
Vol 23 (7) ◽  
pp. 1396-1401 ◽  
Author(s):  
Jocelyn Boily ◽  
René Doucet

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.


2007 ◽  
Vol 37 (4) ◽  
pp. 750-762 ◽  
Author(s):  
Sarah L. Taylor ◽  
David A. MacLean

Forest management prescriptions increasingly incorporate snag and downed dead wood (DDW) guidelines. This study utilizes permanent inventory plots to determine dead wood dynamics in 33 balsam fir ( Abies balsamea (L.) Mill.) – spruce ( Picea spp.) (BFSP) and 17 spruce – balsam fir (SPBF) stands in New Brunswick, Canada. Stands were declining, unmanaged, and had a history of recurrent spruce budworm ( Choristoneura fumiferana (Clem.)) outbreaks and aerial insecticide spraying. Fixed-area sampling matched remnants of 1165 dead trees and 864 corresponding pieces of DDW to plot trees that died over the last 15–18 years with known year and cause of death. Declining BFSP stands had the highest accumulation of dead wood (196 m3/ha) compared with SPBF and nondeclining BFSP (122 m3/ha and 77 m3/ha, respectively). Dead wood dynamics were influenced by cause of death, as a function of differences in tree height at death affecting snag decay, fragmentation, and fall. One-half of all dead trees never made a significant contribution to the snag population (25% uprooted and 25% stem breakage), and attrition resulted in only 50% of snags standing with a mean height of 6 m 15–20 years after death. This study will be of direct value to those managing or modeling dead wood dynamics in similar forests.


2006 ◽  
Vol 82 (5) ◽  
pp. 675-689 ◽  
Author(s):  
Julie Dubois ◽  
Jean-Claude Ruel ◽  
Jean-Gabriel Elie ◽  
Louis Archambault

A total of 48 plots originating from clearcuts were studied in the balsam fir-yellow birch ecological domain of the province of Quebec, Canada, using dendrochronology. The aim of the study was to assess the effect of pre-cut stand type, structure and abundance of regeneration after logging, and soil type on stand dynamics. Results indicate a relationship between pre-cut stand type and the composition of second-growth stands. Ecological characteristics must be taken into account in order to estimate the abundance of advance regeneration and predict the evolution of stocking. Results also show that the structure of regeneration, described by a diameter index, can help in predicting yield at age 38. Devastation by the spruce budworm played a major role in second-growth stand dynamics making it difficult to predict balsam fir yield. The study has also shown an increase in intolerant hardwoods and a low softwood production on rich sites. Black spruce stands came back to black spruce.Key words: mixedwoods, succession, regeneration survey, yield, Choristoneura fumiferana


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