scholarly journals Wildfire-mediated vegetation change in boreal forests of Alberta, Canada

Ecosphere ◽  
2018 ◽  
Vol 9 (3) ◽  
pp. e02156 ◽  
Author(s):  
Diana Stralberg ◽  
Xianli Wang ◽  
Marc-André Parisien ◽  
François-Nicolas Robinne ◽  
Péter Sólymos ◽  
...  
Keyword(s):  
Boreal Forests ◽  
Vegetation Change

Determinants of ~1000-year woody vegetation dynamics at the southern boreal forest margin in Northeast China

2020 ◽  
Author(s):  
Chenyi Zhu ◽  
Hongyan Liu ◽  
Hongya Wang ◽  
Siwen Feng ◽  
Yue Han
Keyword(s):  
Boreal Forest ◽  
Boreal Forests ◽  
Carbon Stock ◽  
Vegetation Change ◽  
Vegetation History ◽  
Permafrost Degradation ◽  
Vegetation Development ◽  
Southern Boundary ◽  
Complete Replacement ◽  
Permafrost Thawing

<p>The most dramatic permafrost degradation is expected to occur at its southernmost distribution, which causes significant vegetation changes in the southernmost boreal forests and consequently affects the carbon stock. To reveal determinants of vegetation change and, in particular, the role of permafrost dynamics, the reconstruction of the long- term vegetation history spanning a warming-cooling cycle is required. Here, we showed that over the last 990 years, vegetation development was characterized by changes in the relative proportions of taxa, such as<em> Larix</em>, <em>Pinus</em> and <em>Corylus</em>, corresponding to the variation in temperature. However, since ~1950 AD, rapid warming has led to the breakdown of the stable relationship among vegetation, climate and permafrost, and the proportion of conifers has shown an increasing trend in the short term due to the influence of permafrost thawing regulated by terrain. In general, we have observed that the coupling system of vegetation, climate and permafrost was stable before ~1950 AD; however, there has been a transition in the most recent rapid warming-induced permafrost thawing. As the southern boundary of permafrost moves northward, it is suspected that the boreal forest in this region will be unstable or may even collapse in the future, and the complete replacement of conifers by broad-leaved trees could greatly reduce the carbon stock in this area by that time.</p>

Twenty-five years of vegetation change along a putative successional chronosequence on the Tanana River, AlaskaThis article is one of a selection of papers from The Dynamics of Change in Alaska’s Boreal Forests: Resilience and Vulnerability in Response to Climate Warming.

2010 ◽  
Vol 40 (7) ◽  
pp. 1273-1287 ◽  
Author(s):  
Teresa N. Hollingsworth ◽  
Andrea H. Lloyd ◽  
Dana R. Nossov ◽  
Roger W. Ruess ◽  
Brian A. Charlton ◽  
...  
Keyword(s):  
Plant Community ◽  
Boreal Forests ◽  
Vegetation Change ◽  
Turning Points ◽  
Community Change ◽  
Ecosystem Structure ◽  
Mature Trees ◽  
Successional Stage ◽  
Long Term Ecological Research

Along the Tanana River floodplain, several turning points have been suggested to characterize the changes in ecosystem structure and function that accompany plant community changes through primary succession. In the past, much of this research focused on a presumed chronosequence that uses space for time substitutions. Within this chronosequence, permanent vegetation plots repeatedly measured over time provide an excellent test of the turning points model. We analyzed both canopy and understory vegetation data collected since 1987 in the Bonanza Creek Experimental Forest at the Bonanza Creek Long Term Ecological Research site to address the following questions: (i) Do long-term changes in the densities of seedling, sapling, and mature trees and shrubs of the dominant woody taxa at each successional stage support the turning points model? (ii) How does the entire plant community change with time at each hypothesized turning point? (iii) Do we see evidence of directional and synchronous shifts in species composition across successional stages? We conclude that some aspects of vegetation change during the last 25 years were consistent with the turning points model; however, many changes were not consistent, indicating the potential roles of biological, environmental, landscape, and climate controls in vegetation patterns.

Late Quaternary vegetation and climate history of the central Bering land bridge from St. Michael Island, western Alaska

2003 ◽  
Vol 60 (1) ◽  
pp. 19-32 ◽  
Author(s):  
Thomas A. Ager
Keyword(s):  
Boreal Forests ◽  
Vegetation Change ◽  
Late Quaternary ◽  
Land Bridge ◽  
Climate History ◽  
Middle Holocene ◽  
Bering Land Bridge ◽  
Dwarf Birch ◽  
History Of ◽  
Vegetation And Climate

AbstractPollen analysis of a sediment core from Zagoskin Lake on St. Michael Island, northeast Bering Sea, provides a history of vegetation and climate for the central Bering land bridge and adjacent western Alaska for the past ≥30,000 14C yr B.P. During the late middle Wisconsin interstadial (≥30,000–26,000 14C yr B.P.) vegetation was dominated by graminoid-herb tundra with willows (Salix) and minor dwarf birch (Betula nana) and Ericales. During the late Wisconsin glacial interval (26,000–15,000 14C yr B.P.) vegetation was graminoid-herb tundra with willows, but with fewer dwarf birch and Ericales, and more herb types associated with dry habitats and disturbed soils. Grasses (Poaceae) dominated during the peak of this glacial interval. Graminoid-herb tundra suggests that central Beringia had a cold, arid climate from ≥30,000 to 15,000 14C yr B.P. Between 15,000 and 13,000 14C yr B.P., birch shrub-Ericales-sedge-moss tundra began to spread rapidly across the land bridge and Alaska. This major vegetation change suggests moister, warmer summer climates and deeper winter snows. A brief invasion of Populus (poplar, aspen) occurred ca.11,000–9500 14C yr B.P., overlapping with the Younger Dryas interval of dry, cooler(?) climate. During the latest Wisconsin to middle Holocene the Bering land bridge was flooded by rising seas. Alder shrubs (Alnus crispa) colonized the St. Michael Island area ca. 8000 14C yr B.P. Boreal forests dominated by spruce (Picea) spread from interior Alaska into the eastern Norton Sound area in middle Holocene time, but have not spread as far west as St. Michael Island.

Light, not nitrogen, limits growth of the grass Deschampsia flexuosa in boreal forests

2004 ◽  
Vol 82 (4) ◽  
pp. 430-435 ◽  
Author(s):  
Joachim Strengbom ◽  
Torgny Näsholm ◽  
Lars Ericson
Keyword(s):  
Boreal Forests ◽  
Vegetation Change ◽  
Light Availability ◽  
Relative Importance ◽  
Deschampsia Flexuosa ◽  
Belowground Competition ◽  
Aboveground Competition ◽  
N Treatment ◽  
Vaccinium Myrtillus L ◽  
Positive Effect

Increased nitrogen (N) input in boreal forests has previously been shown to induce a shift from Vaccinium myrtillus L. to Deschampsia flexuosa (L.) Trin. as the dominant understory species. We investigated the relative importance of increased light and N for this shift, in a field experiment. We increased light availability, that is, we reduced aboveground competition from V. myrtillus, and increased N by adding 50 kg N·ha–1. Increased light availability had a positive effect on both the growth rate and final biomass of D. flexuosa. Although N addition increased the uptake of fertilizer N by both species, it had no effect on the growth or biomass of either species. Thus, aboveground competition from V. myrtillus prevented expansion of D. flexuosa, regardless of N treatment. The results suggest that aboveground competition may be more important than belowground competition for structuring understory boreal forest communities. As light availability is important, both the structure and total amount of standing crop will be important for the outcome of species interactions.Key words: aboveground competition, belowground competition, fertilization, natural enemies, nitrogen deposition, vegetation change.

scholarly journals Rapid Changes in Ground Vegetation of Mature Boreal Forests—An Analysis of Swedish National Forest Inventory Data

Forests ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 475
Author(s):  
Bengt Gunnar Jonsson ◽  
Jonas Dahlgren ◽  
Magnus Ekström ◽  
Per-Anders Esseen ◽  
Anton Grafström ◽  
...  
Keyword(s):  
Forest Inventory ◽  
Ecosystem Functioning ◽  
Boreal Forests ◽  
Vegetation Change ◽  
National Forest Inventory ◽  
Ground Vegetation ◽  
National Forest ◽  
Time Lags ◽  
Forest Herbs ◽  
Species Groups

The boreal forest floor vegetation is critical for ecosystem functioning and an important part of forest biodiversity. Given the ongoing global change, knowledge on broad-scale changes in the composition and abundance of different plant species and species groups is hence important for both forest conservation and management. Here, we analyse permanent plot data from the National Forest Inventory (NFI) on changes in the vegetation over a 10-year period in four regions of Sweden. To limit the direct and relatively well-known effects of forest management and associated succession, we only included mature forest stands not influenced by forestry during the 10 years between inventories, and focused on vegetation change mainly related to other factors. Results show strong decrease among many species and species groups. This includes dominant species such as Vaccinimum myrtillus and Deschampsia flexuosa as well as several forest herbs. The only species increasing are some mosses in the southern regions. Our data do not allow for a causal interpretation of the observed patterns. However, the changes probably result from latent succession in combination with climate change and nitrogen deposition, and with time lags complicating the interpretation of their relative importance. Regardless of the cause, the observed changes are on a magnitude that suggest impacts on ecosystem functioning and hence highlight the need for more experimental work.

Syntaxonomy of mid-successional stages of secondary forests of the central elevated part of the Southern Urals

2012 ◽  
pp. 109-134
Author(s):  
P. S. Shirokikh ◽  
A. M. Kunafin ◽  
V. B. Martynenko
Keyword(s):  
Boreal Forests ◽  
Floristic Composition ◽  
Southern Urals ◽  
Secondary Forests ◽  
Natural Forests ◽  
The Southern Urals ◽  
Active Growth ◽  
Tree Layer ◽  
Shade Tolerant Species ◽  
Successional Stages

The secondary birch and aspen forests of middle stages of succession of the central elevated part of the Southern Urals are studied. 4 subassociations, 1 community, and 7 variants in the alliances of Aconito-Piceion and Piceion excelsae are allocated. It is shown that the floristic composition of aspen and birch secondary forests in the age of 60—80 years is almost identical to the natural forests. However, a slight increase the coenotical role of light-requiring species of grasslands and hemiboreal forests in the secondary communities of the class Brachypodio-Betuletea was noticed as well as some reduction of role the shade-tolerant species of nemoral complex and species of boreal forests of the class Vaccinio-Piceetea. Dominant tree layer under the canopy of secondary series is marked by an active growth of natural tree species.

Possible vegetation change in Mountain Altai under climate warming and compiling the prognosis maps

2000 ◽  
pp. 26-31
Author(s):  
E. I. Parfenova ◽  
N. M. Chebakova
Keyword(s):  
Climate Warming ◽  
Vegetation Change ◽  
Climate Change Scenario ◽  
Change Scenario ◽  
Forest Steppe ◽  
Vegetation Map ◽  
Climatic Indices ◽  
Bioclimatic Model ◽  
Open Woodland ◽  
Mountain Taiga

Global climate warming is expected to be a new factor influencing vegetation redistribution and productivity in the XXI century. In this paper possible vegetation change in Mountain Altai under global warming is evaluated. The attention is focused on forest vegetation being one of the most important natural resources for the regional economy. A bioclimatic model of correlation between vegetation and climate is used to predict vegetation change (Parfenova, Tchebakova 1998). In the model, a vegetation class — an altitudinal vegetation belt (mountain tundra, dark- coniferous subalpine open woodland, light-coniferous subgolets open woodland, dark-coniferous mountain taiga, light-coniferous mountain taiga, chern taiga, subtaiga and forest-steppe, mountain steppe) is predicted from a combination of July Temperature (JT) and Complex Moisture Index (CMI). Borders between vegetation classes are determined by certain values of these two climatic indices. Some bioclimatic regularities of vegetation distribution in Mountain Altai have been found: 1. Tundra is separated from taiga by the JT value of 8.5°C; 2. Dark- coniferous taiga is separated from light-coniferous taiga by the CMI value of 2.25; 3. Mountain steppe is separated from the forests by the CMI value of 4.0. 4. Within both dark-coniferous and light-coniferous taiga, vegetation classes are separated by the temperature factor. For the spatially model of vegetation distribution in Mountain Altai within the window 84 E — 90 E and 48 N — 52 N, the DEM (Digital Elevation Model) was used with a pixel of 1 km resolution. In a GIS Package IDRISI for Windows 2.0, climatic layers were developed based on DEM and multiple regressions relating climatic indices to physiography (elevation and latitude). Coupling the map of climatic indices with the authors' bioclimatic model resulted into a vegetation map for the region of interest. Visual comparison of the modelled vegetation map with the observed geobotanical map (Kuminova, 1960; Ogureeva, 1980) showed a good similarity between them. The new climatic indices map was developed under the climate change scenario with summer temperature increase 2°C and annual precipitation increase 20% (Menzhulin, 1998). For most mountains under such climate change scenario vegetation belts would rise 300—400 m on average. Under current climate, the dark-coniferous and light-coniferous mountain taiga forests dominate throughout Mountain Altai. The chern forests are the most productive and floristically rich and are also widely distributed. Under climate warming, light-coniferous mountain taiga may be expected to transform into subtaiga and forest-steppe and dark-coniferous taiga may be expected to transform partly into chern taiga. Other consequences of warming may happen such as the increase of forest productivity within the territories with sufficient rainfall and the increase of forest fire occurrence over territories with insufficient rainfall.

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