Changes in nutrient availability and forest floor characteristics in relation to stand age and forest composition in the southern part of the boreal forest of northwestern Quebec

Postfire succession in the Alaskan boreal forest follows several different pathways, the most common being self-replacement and species-dominance relay. In self-replacement, canopy-dominant tree species replace themselves as the postfire dominants. It implies a relatively unchanging forest composition through time maintained by trees segregated within their respective, ecophysiological niches on an environmentally complex landscape. In contrast, species-dominance relay involves the simultaneous, postfire establishment of multiple tree species, followed by later shifts in canopy dominance. It implies that stand compositions vary with time since last fire. The relative frequencies of these and other successional pathways are poorly understood, despite their importance in determining the species mosaic of the present forest and their varying, potential responses to climate changes. Here we assess the relative frequencies of different successional pathways by modeling the relationship between stand type, solar insolation, and altitude; by describing how stand age relates to species composition; and by inferring successional trajectories from stand understories. Results suggest that >70% of the study forest is the product of self-replacement, and tree distributions are controlled mainly by the spatial distribution of solar insolation and altitude, not by time since last fire. As climate warms over the coming decades, deciduous trees will invade cold sites formerly dominated by black spruce, and increased fire frequency will make species-dominance relay even rarer.

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Relationships between Structure, Composition, and Dynamics of the Pristine Northern Boreal Forest and Air Temperature, Precipitation, and Soil Texture in Quebec (Canada)

International Journal of Forestry Research ◽

10.1155/2009/398389 ◽

2009 ◽

Vol 2009 ◽

pp. 1-13 ◽

Cited By ~ 2

Author(s):

Louis Duchesne ◽

Rock Ouimet

Keyword(s):

Boreal Forest ◽

Air Temperature ◽

Tree Growth ◽

Soil Texture ◽

Forest Composition ◽

Stand Age ◽

Stand Dynamics ◽

Precipitation Regime ◽

Temperature And Precipitation ◽

Precipitation Regimes

This study reports on the contemporary structure, composition, and dynamics of the pristine northern boreal forest in Quebec, Canada, associated with air temperature, precipitation, and soil texture, using 147 permanent sample plots located at the limit of continuous forest in Quebec. The results show that tree species composition of stands is associated with stand age, soil texture, air temperature, and precipitation regime. After establishment of the pioneer cohort, the postsuccessional stand dynamics differed among temperature and precipitation regimes, probably because of their influence on tree growth. Our results support the hypothesis that shifts in forest composition related to stand dynamics and the subsequent senescing phase associated with the old growth stage generally occur sooner and proceed faster on more fertile sites due to quicker growth and the subsequent earlier mortality of pioneer species. This study suggests that climate warming should accelerate the successional dynamics of these ecosystems through its positive influence on tree growth.

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Coarse woody debris in the southeastern Canadian boreal forest: composition and load variations in relation to stand replacement

Canadian Journal of Forest Research ◽

10.1139/x99-256 ◽

2000 ◽

Vol 30 (5) ◽

pp. 674-687 ◽

Cited By ~ 63

Author(s):

C Hély ◽

Y Bergeron ◽

M D Flannigan

Keyword(s):

Boreal Forest ◽

Coarse Woody Debris ◽

Structural Characteristics ◽

Woody Debris ◽

Decay Rates ◽

Forest Composition ◽

Stand Age ◽

Time Since Fire ◽

Clay Deposits ◽

Canopy Composition

Quantities and structural characteristics of coarse woody debris (CWD) (logs and snags) were examined in relation to stand age and composition in the Canadian mixedwood boreal forest. Forty-eight stands originating after fire (from 32 to 236 years) were sampled on mesic clay deposits. The point-centered quadrant method was used to record canopy composition and structure (living trees and snags). The line-intersect method was used to sample logs of all diameters. Total log load, mean snag density, and volume per stand were similar to other boreal stands. Linear and nonlinear regressions showed that time since fire and canopy composition were significant descriptors for log load changes, whereas time since fire was the only significant factor for snag changes. Coarse woody debris accumulation models through time since fire were different from the U-shaped model because the first initial decrease from residual pre-disturbance debris was missing, the involved species had rapid decay rates with no long-term accumulation, and the succession occurred from species replacement through time.

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Chemical composition of forest floor and consequences for nutrient availability after wildfire and harvesting in the boreal forest

Plant and Soil ◽

10.1007/s11104-008-9604-6 ◽

2008 ◽

Vol 308 (1-2) ◽

pp. 37-53 ◽

Cited By ~ 45

Author(s):

E. Thiffault ◽

K. D. Hannam ◽

S. A. Quideau ◽

D. Paré ◽

N. Bélanger ◽

...

Keyword(s):

Chemical Composition ◽

Boreal Forest ◽

Nutrient Availability ◽

Forest Floor

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Interactions with successional stage and nutrient status determines the life-form-specific effects of increased soil temperature on boreal forest floor vegetation

Ecology and Evolution ◽

10.1002/ece3.1412 ◽

2015 ◽

Vol 5 (4) ◽

pp. 948-960 ◽

Cited By ~ 9

Author(s):

Per-Ola Hedwall ◽

Jerry Skoglund ◽

Sune Linder

Keyword(s):

Boreal Forest ◽

Soil Temperature ◽

Forest Floor ◽

Life Form ◽

Nutrient Status ◽

Successional Stage ◽

Specific Effects ◽

Forest Floor Vegetation

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Logging impacts on the biogeochemistry of boreal forest soils and nutrient export to aquatic systems: A review

Environmental Reviews ◽

10.1139/a08-006 ◽

2008 ◽

Vol 16 (NA) ◽

pp. 157-179 ◽

Cited By ~ 184

Author(s):

David P. Kreutzweiser ◽

Paul W. Hazlett ◽

John M. Gunn

Keyword(s):

Boreal Forest ◽

Nutrient Availability ◽

Soil Nutrient ◽

Soil Conditions ◽

Soil Nutrient Availability ◽

Clear Cutting ◽

Partial Harvest ◽

Forest Watersheds ◽

Logging Impacts ◽

Receiving Waters

Logging disturbances in boreal forest watersheds can alter biogeochemical processes in soils by changing forest composition, plant uptake rates, soil conditions, moisture and temperature regimes, soil microbial activity, and water fluxes. In general, these changes have often led to short-term increases in soil nutrient availability followed by increased mobility and losses by leaching to receiving waters. Among the studies we reviewed, dissolved organic carbon (DOC) exports usually increased after logging, and nitrogen (N) mineralization and nitrification often increased with resulting increased N availability and exports to receiving waters. Similar processes and responses occurred for phosphorus (P), but to a lesser extent than for N. In most cases, base cations were released and exported to receiving waters after logging. Several studies demonstrated that stem-only or partial-harvest logging reduced the impacts on nutrient release and exports in comparison to whole-tree clear-cutting. Despite these logging-induced increases in soil nutrient availability and movement to receiving waters, most studies reported little or no change in soil chemical properties. However, responses to logging were highly variable and often site specific. The likelihood, extent and magnitude of logging impacts on soil nutrient cycling and exports in boreal forest watersheds will be dependent on soil types, stand and site conditions, hydrological connectivity, post-logging weather patterns, and type and timing of harvest activities. Additionally, logging impacts can interact with, and be confounded by, atmospheric pollutant deposition and climate change. Further watershed-level empirical studies and modeling efforts are required to elucidate these interactions, to improve predictive capabilities, and to advance forest management guidelines for sustaining forest soil productivity and limiting nutrient exports.

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Soil Organic Carbon Stocks in Afforested Agricultural Land in Lithuanian Hemiboreal Forest Zone

Forests ◽

10.3390/f12111562 ◽

2021 ◽

Vol 12 (11) ◽

pp. 1562

Author(s):

Iveta Varnagirytė-Kabašinskienė ◽

Povilas Žemaitis ◽

Kęstutis Armolaitis ◽

Vidas Stakėnas ◽

Gintautas Urbaitis

Keyword(s):

Organic Carbon ◽

Soil Organic Carbon ◽

Forest Floor ◽

Agricultural Land ◽

Forest Stand ◽

Stand Age ◽

Soc Stock ◽

The Mean ◽

Soc Stocks ◽

Topsoil Layer

In the context of the specificity of soil organic carbon (SOC) storage in afforested land, nutrient-poor Arenosols and nutrient-rich Luvisols after afforestation with coniferous and deciduous tree species were studied in comparison to the same soils of croplands and grasslands. This study analysed the changes in SOC stock up to 30 years after afforestation of agricultural land in Lithuania, representing the cool temperate moist climate region of Europe. The SOC stocks were evaluated by applying the paired-site design. The mean mass and SOC stocks of the forest floor in afforested Arenosols increased more than in Luvisols. Almost twice as much forest floor mass was observed in coniferous than in deciduous stands 2–3 decades after afforestation. The mean bulk density of fine (<2 mm) soil in the 0–30 cm mineral topsoil layer of croplands was higher than in afforested sites and grasslands. The clear decreasing trend in mean bulk density due to forest stand age with the lowest values in the 21–30-year-old stands was found in afforested Luvisols. In contrast, the SOC concentrations in the 0–30 cm mineral topsoil layer, especially in Luvisols afforested with coniferous species, showed an increasing trend due to the influence of stand age. The mean SOC values in the 0–30 cm mineral topsoil layer of Arenosols and Luvisols during the 30 years after afforestation did not significantly differ from the adjacent croplands or grasslands. The mean SOC stock slightly increased with the forest stand age in Luvisols; however, the highest mean SOC stock was detected in the grasslands. In the Arenosols, there was higher SOC accumulation in the forest floor with increasing stand age than in the Luvisols, while the proportion of SOC stocks in mineral topsoil layers was similar and more comparable to grasslands. These findings suggest encouragement of afforestation of former agricultural land under the current climate and soil characteristics in the region, but the conversion of perennial grasslands to forest land should be done with caution.

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Microbial Substrate Utilization and Vegetation Shifts in Boreal Forest Floors of Western Canada

Frontiers in Forests and Global Change ◽

10.3389/ffgc.2021.700751 ◽

2021 ◽

Vol 4 ◽

Author(s):

Emily Lloret ◽

Sylvie Quideau

Keyword(s):

Boreal Forest ◽

Microbial Communities ◽

Forest Floor ◽

Microbial Respiration ◽

Substrate Utilization ◽

Utilization Efficiency ◽

Western Canada ◽

Spruce Forest ◽

Vegetation Shifts ◽

Forest Floors

Boreal forest soils are highly susceptible to global warming, and in the next few decades, are expected to face large increases in temperature and transformative vegetation shifts. The entire boreal biome will migrate northward, and within the main boreal forest of Western Canada, deciduous trees will replace conifers. The main objective of our research was to assess how these vegetation shifts will affect functioning of soil microbial communities and ultimately the overall persistence of boreal soil carbon. In this study, aspen and spruce forest floors from the boreal mixedwood forest of Alberta were incubated in the laboratory for 67 days without (control) and with the addition of three distinct 13C labeled substrates (glucose, aspen leaves, and aspen roots). Our first objective was to compare aspen and spruce substrate utilization efficiency (SUE) in the case of a labile C source (13C-glucose). For our second objective, addition of aspen litter to spruce forest floor mimicked future vegetation shifts, and we tested how this would alter substrate use efficiency in the spruce forest floor compared to the aspen. Tracking of carbon utilization by microbial communities was accomplished using 13C-PLFA analysis, and 13C-CO2 measurements allowed quantification of the relative contribution of each added substrate to microbial respiration. Following glucose addition, the aspen community showed a greater 13C-PLFA enrichment than the spruce throughout the 67-day incubation. The spruce community respired a greater amount of 13C glucose, and it also had a much lower glucose utilization efficiency compared to the aspen. Following addition of aspen litter, in particular aspen leaves, the aspen community originally showed greater total 13C-PLFA enrichment, although gram positive phospholipid fatty acids (PLFAs) were significantly more enriched in the spruce community. While the spruce community respired a greater amount of the added 13C-leaves, both forest floor types showed comparable substrate utilization efficiencies by Day 67. These results indicate that a shift from spruce to aspen may lead to a greater loss of the aspen litter through microbial respiration, but that incorporation into microbial biomass and eventually into the more persistent soil carbon pool may not be affected.

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