Évolution de la structure diamétrale et de la composition des peuplements mixtes de sapin baumier et d'épinette rouge de la forêt primitive après une coupe à diamètre limite sur l'Aire d'observation de la rivière Ouareau

2003 ◽  
Vol 33 (4) ◽  
pp. 691-704 ◽  
Author(s):  
Mathieu Fortin ◽  
Jean Bégin ◽  
Louis Bélanger

Using data from 41 plots, the diameter structure and composition of old-growth mixed stands composed mainly of balsam fir (Abies basalmea (L.) Mill.) and red spruce (Picea rubens Sarg.) were characterized. The stand table was organized in five groups of diameter classes, and we characterized the basal area of four tree species in each group. Analysis showed that diameter structure tends toward a reverse J-shaped curve. Red spruce and yellow birch (Betula alleghaniensis Britt.) were more abundant among large diameter trees while balsam fir was more abundant among saplings. A comparison with 18 permanent plots from a diameter-limit cutting showed that plots had come back to a structure similar to that of the old-growth forest 47 years after cutting. However, spruce ratios had decreased while those of balsam fir and paper birch (Betula papyrifera Marsh.) had increased. Red spruce decrease is not due to a lack of regeneration but to overcutting. Single-tree selection method would be a suitable treatment if aimed at protecting red spruce trees up to a given diameter.

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1069
Author(s):  
Taylor M. Buskey ◽  
Margaret E. Maloney ◽  
Julia I. Chapman ◽  
Ryan W. McEwan

Temperate forests of eastern North America are subject to multiple invasions from non-native species that have the potential to drive long-term dynamics in biodiversity. Garlic mustard (Alliaria petiolata (M. Bieb.) Cavara and Grande) is an invasive plant in many deciduous forests, and management efforts often focus on removing this species to initiate native species restoration. Agrilus planipennis Fairmaire (emerald ash borer; Coleoptera: Buprestidae) is a non-native insect pest that has caused substantial loss of ash trees (Fraxinus spp. L.) in North America. Our goal was to understand how the herbaceous layer in an old-growth forest responded to the removal of a significant invasion of A. petiolata and the loss of Fraxinus spp. due to A. planipennis. Herbaceous diversity and environmental parameters were measured in 32 permanent plots (1 m2 each) from 2012 to 2020 in an old-growth forest remnant that had experienced A. petiolata invasion and subsequent removal as well as mortality of Fraxinus spp. due to A. planipennis. Near-total loss of Fraxinus spp. as a canopy tree was not associated with changes in the understory light environment, possibly due to rapid canopy closure by adjacent trees not susceptible to the insect. Alliaria petiolata removal was associated with changes in herbaceous species richness and possibly shifts in individual species importance. Vegetation–environment relationships remained stable throughout the sampling period, suggesting that resource-related factors that structure the herb layer prevailed throughout the changes associated with Fraxinus spp. mortality and A. petiolata management. From a natural area management perspective, our data offer support for the idea that A. petiolata removal influences herb-layer diversity and indicate that in stands with a diverse tree community, the loss of Fraxinus spp. may not directly influence understory biodiversity.


1982 ◽  
Vol 12 (1) ◽  
pp. 18-28 ◽  
Author(s):  
Phillip Sollins

At 10 locations in Oregon and Washington, tree mortality resulted in dry-matter transfer of 1.5–4.5 Mg•ha−1•year−1 of boles and branches to the forest floor and 0.3–1.3 Mg•ha−1•year−1 of large-diameter roots directly to the mineral soil. The first value is about the same as that reported for leaf fall in similar stands; the second value generally is smaller than that reported for fine root turnover. Results are based on measurements by the U.S. Forest Service spanning 16–46 years and areas as large as 42 ha. Values based on intervals < 10 years were highly variable and potentially misleading.At an old-growth Douglas-fir stand in Washington, fallen boles accounted for 81 Mg/ha, standing dead for 54 Mg/ha. Density of fallen boles averaged from 0.14 to 0.27 g/cm3 depending on decay state. Values were lower than some previously reported because (1) our sample included small-diameter fallen boles that tend to decay rapidly, and (2) we measured density with techniques that minimized compaction and shrinkage.The decay rate at the old-growth stand, calculated indirectly by dividing bole mortality (megagrams per hectare per year) by the amount (megagrams per hectare) of fallen and standing dead woody material, was 0.028 year−1. This rate, three to five times those previously calculated directly from change in density alone, was almost identical to values calculated elsewhere from change in both volume and density. Decay rates based on change in density alone include only respired and leached material and exclude the large amount of material lost in fragmentation. This study shows the value of permanent plots, undisturbed by salvage logging, for retrospective studies of decomposition, nutrient cycling, and productivity.


2021 ◽  
Vol 4 ◽  
Author(s):  
Jeffrey Opoku-Nyame ◽  
Alain Leduc ◽  
Nicole J. Fenton

Clear cut harvest simplifies and eliminates old growth forest structure, negatively impacting biodiversity. Partial cut harvest has been hypothesized (1) to have less impact on biodiversity than clear cut harvest, and (2) to encourage old growth forest structures. Long-term studies are required to test this hypothesis as most studies are conducted soon after harvest. Using epixylic bryophytes as indicators, this study addresses this knowledge gap. Fourteen years after harvest, we examined changes in epixylic bryophyte community composition richness and traits, and their microhabitats (coarse woody debris characteristics and microclimate) along an unharvested, partial cuts and clear cuts harvest treatment in 30 permanent plots established in the boreal black spruce (Picea mariana) forests of northwestern Quebec, Canada. Our results were compared to those of an initial post-harvest study (year 5) and to a chronosequence of old growth forests to examine species changes over time and the similarity of bryophyte communities in partial cut and old growth forests. Coarse woody debris (CWD) volume by decay class varied among harvest treatments with partial cuts and clear cuts recording lower volumes of early decay CWD. The epixylic community was richer in partial cuts than in mature unharvested forests and clear cuts. In addition, species richness and overall abundance doubled in partial and clear cuts between years 5 and 14. Species composition also differed among treatments between years 5 and 14. Furthermore, conditions in partial cut stands supported small, drought sensitive, and old growth confined species that are threatened by conditions in clear cut stands. Lastly, over time, species composition in partial cuts became more similar to old growth forests. Partial cuts reduced harvest impacts by continuing to provide favorable microhabitat conditions that support epixylic bryophytes. Also, partial cut harvest has the potential to encourage old growth species assemblages, which has been a major concern for biodiversity conservation in managed forest landscapes. Our findings support the promotion of partial cut harvest as an effective strategy to achieve species and habitat conservation goals.


2005 ◽  
Vol 81 (6) ◽  
pp. 791-800 ◽  
Author(s):  
Mathieu Fortin

Diameter growth at breast height of 341 balsam fir and red spruce stems has been reproduced over a time lapse of 50 years following a diameter limit cutting. The available information has been analyzed with a statistical model in which the effects of time, species (two levels), ecological type (three levels) and diameter at harvesting have been tested. Results indicate that balsam fir saplings have higher diameter growths than red spruce saplings, but only in the case of better ecological types. The differences between both species are smaller for stems having a merchantable diameter (dbh > 9.0 cm) at harvesting time. On poor ecological station, red spruce diameter growth is more important than for balsam fir and this, whatever the diameter at harvesting time. On the other hand, as indicated by this analysis, stem diameter at the time of silvicultural treatment constitutes a significant variable in the prediction of diameter growth for red spruce stems, while the effect of this variable is less identifiable for balsam fir. Even if significant, the growth differences between the two species are small. The competition created by the balsam fir regeneration on red spruce saplings is definitely not the cause of the depletion of red spruce in second growth stands.. Key words: red spruce (Picea rubens Sarg.), balsam fir (Abies balsamea (L.) Mill.), diameter growth, partial cut, mixed stands, linear model, mixed model


2004 ◽  
Vol 82 (6) ◽  
pp. 830-849 ◽  
Author(s):  
Mireille Desponts ◽  
Geneviève Brunet ◽  
Louis Bélanger ◽  
Mathieu Bouchard

The objective of this project was to assess the importance of pristine forests in maintaining the botanical biodiversity of the humid boreal balsam fir forest of eastern Canada. The study was based on a comparative analysis of silviculturally mature second-growth stands and pristine forest stands at two stages of development (senescent and old growth) in the Gaspé Peninsula. The structure and composition of the stands was described, and the abundance of structural attributes evaluated. The communities of nonvascular plant species (mosses, liverworts), lichens, and saprophytic fungi were compared. The study demonstrated that the pristine forest landscape studied was composed largely of old-growth and senescent stands. Old-growth forests are differentiated by their irregular structure. The results regarding nonvascular plant species, lichens, and saprophytic fungi show higher species diversity in old-growth forests, corresponding to higher habitat diversity. Species assemblages were comparable between the pristine forests, but different from those of second-growth stands. Rare species are found more frequently in the old-growth forests. The results indicate that the old-growth balsam fir stands of the Gaspé Peninsula constitute critical habitats for maintaining a large number of species threatened by the gradual disappearance of primeval stands.Key words: forest management, biodiversity, old-growth forest, humid boreal fir forest, nonvascular plants.


1999 ◽  
Vol 75 (3) ◽  
pp. 515-534 ◽  
Author(s):  
Pierre Pominville ◽  
Stéphane Déry ◽  
Louis Bélanger

An outbreak of spruce budworm, Choristoneura fumiferana (Clem.), occurred between 1974 and 1987, in Quebec, in the eastern balsam fir, Abies balsamea (L.) Mill, - yellow birch, Betula alleghaniensis Britton, ecoclimatic sub-domain. The effect of this disruption has been assessed in mesic balsam fir stands killed during the outbreak, in mesic balsam fir stands partially damaged and in the following stands, also partially damaged: mesic yellow birch – balsam fir stands, mesic white birch, Betulapapyrifera Marsh., - balsam fir stands, mesic balsam fir – yellow birch stands, mesic balsam fir – white birch stands and xeric balsam fir stands. To that effect, surveys were led before, immediately after, and about five years after the outbreak in two blocks that have not been protected with insecticides. These blocks, located in Charlevoix and in Shipshaw management units, are second growth stands originating from clearcuts which occured about 50 years ago. Approximately five years after the outbreak, abundant coniferous regeneration was found everywhere except in the mesic yellow birch –balsam fir stand and in the dead mesic balsam fir stand, where softwood represented less than 50% of the regeneration. On the other hand, young softwood stems were located under the regeneration of white birch and of mountain maple, Acer spicatum Lam, in dead balsam fir stands, in balsam fir – white birch stands, as well as in living balsam fir stands and under mountain maple in yellow birch – balsam fir stands and in balsam fir – yellow birch stands. Our age structures indicate that softwood advance growth was relatively rare in these stands. Thus, during the opening of the canopy by the spruce budworm, intolerant hard-woods and shrubs invaded the still available microsites. In the dead balsam fir stands, stocking of the dominant hardwood regeneration stems is equivalent to that of softwood. Thus, dead balsam fir stands are turning to mixed stands. Xeric stands will remain softwood stands since they show luxuriant softwood regeneration dominating in height. In the other stands, we will have to wait the harvest period before we can adequately assess succession.


2003 ◽  
Vol 79 (3) ◽  
pp. 632-644 ◽  
Author(s):  
Bruce J Stewart ◽  
Peter D Neily ◽  
Eugene J Quigley ◽  
Lawrence K Benjamin

A study of four old-growth stands in Nova Scotia was conducted to document the ecological characteristics of these currently rare Acadian forest ecosystems. Stands were selected to represent the two dominant climax forest types, hemlock–red spruce–eastern white pine, and sugar maple–yellow birch–beech. Data include measurements of age structure, species composition, diameter distribution, basal area, height, coarse woody debris, snags, vertical structure, and canopy condition. All stands were determined to be uneven-aged. Old-growth reference ages calculated for the stands ranged from 164 to 214 years. All stands displayed broad diameter distributions that had peak basal area representation in the 40- to 50-cm diameter classes. Volumes of dead wood ranged from 111 to 148 m3/ha in the softwood stands and from 63 to 83m3/ha in the hardwood stands. Dead wood consisted of approximately one-third snags and two thirds downed coarse woody debris. Measurements from the stands were used to evaluate Nova Scotia's recently developed Old Forest Scoring System. Six stand attributes were rated for a maximum score of 100: stand age, primal value, number of large-diameter trees, length of large-diameter dead wood, canopy structure, and understorey structure. Based on the age attribute, three of the four stands were classed as Mature Old Growth and one was very close, indicating that all are in the shifting mosaic stage of late forest succession. The scores for all stands were relatively high, ranging from 75 to 85, as would be expected from some of the best old-growth stands in the province. Key words: old growth, climax, primal, late succession, uneven-aged, scoring, coarse woody debris, age structure, diameter, Acadian forest, northern hardwood, red spruce, eastern hemlock, white pine, sugar maple, yellow birch, American beech


PLoS ONE ◽  
2015 ◽  
Vol 10 (3) ◽  
pp. e0120335 ◽  
Author(s):  
Andreas Fichtner ◽  
David I. Forrester ◽  
Werner Härdtle ◽  
Knut Sturm ◽  
Goddert von Oheimb

2020 ◽  
Author(s):  
Maxence Martin ◽  
Miguel Montoro Girona ◽  
Hubert Morin

AbstractOld-growth forests play a major role in conserving biodiversity, protecting water resources, sequestrating carbon, and these forests are indispensable resources for indigenous societies. To preserve the ecosystem services provided by these boreal ecosystems, it becomes necessary to develop novel silvicultural practices capable of emulating the natural dynamics and structural attributes of old-growth forests. The success of these forest management strategies depends on developing an accurate understanding of natural regeneration dynamics. Our goal was therefore to identify the main patterns and the drivers involved in the regeneration dynamics of old-growth forests, placing our focus on boreal stands dominated by black spruce (Picea mariana (L.) Mill.) and balsam fir (Balsam fir (L.) Mill.) in eastern Canada. We sampled 71 stands in a 2200 km2 study area located within Quebec’s boreal region. For each stand, we noted tree regeneration (seedlings and saplings), structural attributes (diameter distribution, deadwood volume, etc.), and abiotic (topography and soil) factors. We observed that secondary disturbance regimes and topographic constraints were the main drivers of balsam fir and black spruce regeneration. Furthermore, the regeneration dynamics of black spruce appeared more complex than those of balsam fir. We observed distinct phases of seedling production first developing within the understory, then seedling growth when gaps opened in the canopy, followed by progressive canopy closure. Seedling density, rather than the sapling density, had a major role in explaining the ability of black spruce to fill the canopy following a secondary disturbance. The density of balsam fir seedlings and saplings was also linked to the abundance of balsam fir trees at the stand level. This research helps explain the complexity of old-growth forest dynamics where many ecological factors interact at multiple temporal and spatial scales. This study also improves our understanding of ecological processes within native old-growth forests and identifies the key factors to consider when ensuring the sustainable management of old-growth boreal stands.


2014 ◽  
Vol 99 ◽  
pp. 1-155 ◽  
Author(s):  
Izabela Kałucka

The paper deals with the succession of basidiomycete macrofungi on abandoned farmland. The research was carried out in the unique complex of old fields of different age located on the southwest edge of the Białowieża old-growth forest (NE Poland). These lands undergo spontaneous secondary succession leading to formation of a continental fresh pine forest. Regular observations of basidiomata in 16 permanent plots (11 plots of 1000 m2, 5 plots of 400 m2) representing initial, optimal and terminal stage of vegetation development from psammophilous grassland to a pine forest with 100-year-old tree stand were conducted for three years. Soil and vegetation analyses were also carried out as well as quantitative examination of ectomycorrhizae in root samples. The series yielded 300 species of macromycetes (including 6 collective taxa) found in permanent plots plus 18 species outside the plots. The species composition, spatial distribution of sporocarps, and quantitative structure of fungal communities changed along the successional gradient. Increasing diversity of fungi resulted from persistence of species typical of open areas and species associated with younger trees, as well as accumulation of species associated with older trees and more developed stands. Some species typical of younger phases were replaced with species arriving later in the chronosequence. Species usually occurred long before and after attaining maximum abundance and frequency. Species associated with certain periods of vegetation development could be distinguished, as well as species accompanying the phytocoenoses regardless of their developmental stage. Patterns in structural changes of the fungal community, e.g., in number of species, abundance, frequency and production of carpophores, could also be recognised. They were different in ectomycorrhizal and in saprotrophic fungi. The occurrence of the former was influenced mainly by the presence of symbiotic trees and their age, stand structure and soil properties, while occurrence of the latter was affected by microclimatic factors and by diversity of accessible substrates. Changes in fungal communities were consistent with vegetation changes, but were also specific to this group of organisms.


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