Carbon loss from boreal forest wildfires offset by increased dominance of deciduous trees

Science ◽  
2021 ◽  
Vol 372 (6539) ◽  
pp. 280-283
Author(s):  
Michelle C. Mack ◽  
Xanthe J. Walker ◽  
Jill F. Johnstone ◽  
Heather D. Alexander ◽  
April M. Melvin ◽  
...  
Keyword(s):  
Carbon Storage ◽  
Climate Warming ◽  
Boreal Forests ◽  
Black Spruce ◽  
Organic Soils ◽  
Deciduous Trees ◽  
Ecological Change ◽  
Dominant Plant Species ◽  
Slow Growing

In boreal forests, climate warming is shifting the wildfire disturbance regime to more frequent fires that burn more deeply into organic soils, releasing sequestered carbon to the atmosphere. To understand the destabilization of carbon storage, it is necessary to consider these effects in the context of long-term ecological change. In Alaskan boreal forests, we found that shifts in dominant plant species catalyzed by severe fire compensated for greater combustion of soil carbon over decadal time scales. Severe burning of organic soils shifted tree dominance from slow-growing black spruce to fast-growing deciduous broadleaf trees, resulting in a net increase in carbon storage by a factor of 5 over the disturbance cycle. Reduced fire activity in future deciduous-dominated boreal forests could increase the tenure of this carbon on the landscape, thereby mitigating the feedback to climate warming.

Carbon emissions from fires in permafrost peatlands

2021 ◽  
Author(s):  
Sander Veraverbeke ◽  
Clement Delcourt ◽  
Gustaf Granath ◽  
Elena Kukavskaya ◽  
Michelle Mack ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Climate Warming ◽  
Boreal Forests ◽  
Organic Soils ◽  
Climate Feedbacks ◽  
Soil C ◽  
Fire Emissions ◽  
Degradation Data ◽  
Tundra Ecosystems

<p>Increases in arctic and boreal fires can switch these biomes from a long-term carbon (C) sink to a source through direct fire emissions and longer-term emissions from soil respiration. Landscapes of intermediate drainage tend to experience the highest C combustion, dominated by soil C emissions, because of relatively thick and periodically dry organic soils. These landscapes may also induce a climate warming feedback through combustion and post-fire respiration of legacy C – soil C that had escaped burning in the previous fire – including from permafrost thaw and degradation. Data shortages from fires in tundra ecosystems and Eurasian boreal forests limit our understanding of C emissions from arctic-boreal fires. Interactions between fire, topography, vegetation, soil and permafrost need to be considered when estimating climate feedbacks of arctic-boreal fires.</p>

Deadwood abundance in Labrador high-boreal black spruce forests

2009 ◽  
Vol 39 (1) ◽  
pp. 131-142 ◽  
Author(s):  
Ulrike Hagemann ◽  
Martin T. Moroni ◽  
Franz Makeschin
Keyword(s):  
Boreal Forests ◽  
Black Spruce ◽  
Woody Debris ◽  
Reduction Rate ◽  
Coniferous Forests ◽  
Old Growth ◽  
Clear Cut ◽  
Dead Trees ◽  
Standing Dead

Deadwood (woody debris (WD), standing dead trees (snags), stumps, and buried deadwood) abundance was estimated in Labrador humid high-boreal black spruce (Picea mariana (Mill.) BSP) forests regrown following natural and anthropogenic disturbances. Aboveground deadwood (DW) abundance in Labrador was similar to values observed in other boreal forests experiencing drier or warmer climates. Clear-cut harvest generated large amounts of WD, which had almost completely decomposed 34–36 years following harvesting, with a fitted volume reduction rate of –0.058 year–1. Total WD in all harvested stands was composed of predominantly <10 cm pieces, which should be included in DW inventories of disturbed coniferous boreal forests. Postfire WD likely peaked ∼20 years following disturbance, as a result of the collapse of snags, and was dominated by large amounts of medium-sized logs (10.0–19.9 cm). Buried DW stocks considerably exceeded total aboveground DW stocks in old-growth, middle-aged, and older harvested stands. Old-growth stands contained 179.3 m3·ha–1 of buried DW, a vast amount indicative of long-term accumulation requiring significantly depressed rates of WD decomposition following burial. DW stocks could be significantly underestimated if buried DW is excluded from DW inventories in cool and moist coniferous forests with long fire-return intervals.

Application of shadow fraction models for estimating attributes of northern boreal forests

2012 ◽  
Vol 42 (9) ◽  
pp. 1750-1757 ◽  
Author(s):  
Joan E. Luther ◽  
Richard A. Fournier ◽  
Mélanie Houle ◽  
Antoine Leboeuf ◽  
Douglas E. Piercey
Keyword(s):  
Boreal Forests ◽  
Potential Role ◽  
Black Spruce ◽  
Abies Balsamea ◽  
Basal Area ◽  
Deciduous Trees ◽  
Mean Square Errors ◽  
Fraction Method ◽  
Relative Root

A shadow fraction method was developed previously for mapping forest attributes of northern black spruce ( Picea mariana (Mill.) Britton, Sterns & Poggenb.) forests. This paper evaluates application of the method for (i) balsam fir stands ( Abies balsamea (L.) Mill.), (ii) stands with higher volume and biomass than those of previous studies, and (iii) stands with a higher composition of deciduous trees and steeper slopes. Models developed for new test sites in (i) central Labrador and (ii) western Newfoundland were not statistically different from previous models for biomass, volume, and basal area. Relative root mean square errors (RMSEr) for central Labrador were slightly lower than those found in other test sites (RMSEr: 24%–29%) but higher for western Newfoundland (RMSEr = 37%–43%), attributed to the higher upper limit of measured attributes and increased presence of deciduous trees. Results suggest that reasonable estimates can be generated for conifer forests of northeastern Canada; however, an alternative solution is needed where mixed and deciduous stands are prevalent. Measurement of ground plots over a wider range of species composition and forest structure is recommended for broader application to northern boreal forests and to further assess the potential role of the shadow fraction method in national-scale inventory programs.

Enhanced Seasonal Exchange of CO2 by Northern Ecosystems Since 1960

Science ◽  
2013 ◽  
Vol 341 (6150) ◽  
pp. 1085-1089 ◽  
Author(s):  
H. D. Graven ◽  
R. F. Keeling ◽  
S. C. Piper ◽  
P. K. Patra ◽  
B. B. Stephens ◽  
...  
Keyword(s):  
Boreal Forests ◽  
Atmospheric Carbon Dioxide ◽  
Ecosystem Models ◽  
The North ◽  
Ecological Changes ◽  
Term Change ◽  
Major Shift ◽  
Underlying Mechanisms ◽  
Global Carbon

Seasonal variations of atmospheric carbon dioxide (CO2) in the Northern Hemisphere have increased since the 1950s, but sparse observations have prevented a clear assessment of the patterns of long-term change and the underlying mechanisms. We compare recent aircraft-based observations of CO2 above the North Pacific and Arctic Oceans to earlier data from 1958 to 1961 and find that the seasonal amplitude at altitudes of 3 to 6 km increased by 50% for 45° to 90°N but by less than 25% for 10° to 45°N. An increase of 30 to 60% in the seasonal exchange of CO2 by northern extratropical land ecosystems, focused on boreal forests, is implicated, substantially more than simulated by current land ecosystem models. The observations appear to signal large ecological changes in northern forests and a major shift in the global carbon cycle.

Long‐term effect of tillage and straw retention in conservation agriculture systems on soil carbon storage

2021 ◽  
Author(s):  
Beatriz Gómez‐Muñoz ◽  
Lars Stoumann Jensen ◽  
Lars Munkholm ◽  
Jørgen Eivind Olesen ◽  
Elly Møller Hansen ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Carbon Storage ◽  
Conservation Agriculture ◽  
Term Effect ◽  
Soil Carbon Storage ◽  
Long Term Effect ◽  
Straw Retention ◽  
Agriculture Systems

Land conversion regulates the effects of long-term climate warming on soil micro-food web communities

2021 ◽  
Vol 314 ◽  
pp. 107426
Author(s):  
Pingting Guan ◽  
Mohammad Mahamood ◽  
Yurong Yang ◽  
Donghui Wu
Keyword(s):  
Food Web ◽  
Climate Warming ◽  
Land Conversion ◽  
Web Communities
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