Carbon dynamics of aboveground live vegetation of boreal mixedwoods after wildfire and clear-cutting

2010 ◽  
Vol 40 (9) ◽  
pp. 1862-1869 ◽  
Author(s):  
Meelis Seedre ◽  
Han Y.H. Chen

Live vegetation carbon (C) pool dynamics are central to understanding C sequestration of forest ecosystems. Despite its importance, how aboveground live C pools change with stand development in boreal mixedwoods is poorly understood. We quantified aboveground live C pools (i.e., trees, >4 m in height; saplings and shrubs, 1.3–4 m in height; and understory plants, <1.3 m in height) in a postfire chronosequence ranging from 1 to 203 years and a postlogging chronosequence ranging from 1 to 27 years in the boreal mixedwoods of central Canada. The tree C pool of postfire stands increased from 0 to 109.2 Mg/ha from 1 to 92 years after fire and then declined to approximately 70 Mg/ha in 140- and 203-year-old stands. Carbon pools of saplings and shrubs and understory plants also changed with stand development and stand origin. Of the three age classes compared, postlogged stands had significantly higher vegetation C than postfire stands 1 and 27 years after disturbance, but there was no difference in 9-year-old stands. Higher values of live vegetation C in postlogged stands was attributed to live standing trees left after logging and silvicultural treatments that helped trees to establish during stand initiation.

2021 ◽  
Author(s):  
Carl-Fredrik Johannesson ◽  
Klaus Steenberg Larsen ◽  
Brunon Malicki ◽  
Jenni Nordén

&lt;p&gt;Boreal forests are among the most carbon (C) rich forest types in the world and store up to 80% of its total C in the soil. Forest soil C development under climate change has received increased scientific attention yet large uncertainties remain, not least in terms of magnitude and direction of soil C responses. As with climate change, large uncertainties remain in terms of the effects of forest management on soil C sequestration and storage. Nonetheless, it is clear that forest management measures can have far reaching effects on ecosystem functioning and soil conditions. For example, clear cutting is a widely undertaken felling method in Scandinavia which profoundly affects the forest ecosystem and its functioning, including the soil. Nitrogen (N) fertilization is another common practice in Scandinavia which, despite uncertainties regarding effects on soil C dynamics, is being promoted as a climate change mitigation tool. A more novel practice of biochar addition to soils has been shown to have positive effects on soil conditions, including soil C storage, but studies on biochar in the context of forests are few.&lt;/p&gt;&lt;p&gt;In the face of climate change, the ForBioFunCtioN project is dedicated to investigating the response of boreal forest soil CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; fluxes to experimentally increased temperatures and increased precipitation &amp;#8211; climatic changes in line with projections over Norway &amp;#8211; within a forest management context. The experiment is set in a Norwegian spruce-dominated bilberry chronosequence, including a clear-cut site, a middle-aged thinned stand, a mature stand and an old unmanaged stand. Warming, simulated increased precipitation, N fertilizer and biochar additions will be applied on experimental plots in an additive manner that allows for disentangling the effects of individual parameters from interaction effects. Flux measurements will be undertaken at high temporal resolution using the state-of-the-art LI-7810 Trace Gas Analyzer (&amp;#169;LI-COR Biosciences). The presentation will show the experimental setup and first measurements from the large-scale experiment.&lt;/p&gt;


2015 ◽  
Vol 300 ◽  
pp. 123-136 ◽  
Author(s):  
Arun K. Bose ◽  
Brian D. Harvey ◽  
K. David Coates ◽  
Suzanne Brais ◽  
Yves Bergeron

Soil Research ◽  
2018 ◽  
Vol 56 (4) ◽  
pp. 413 ◽  
Author(s):  
Kumari Priyanka ◽  
Anshumali

Loss of labile carbon (C) fractions yields information about the impact of land-use changes on sources of C inputs, pathways of C losses and mechanisms of soil C sequestration. This study dealt with the total organic C (TOC) and labile C pools in 40 surface soil samples (0–15 cm) collected from four land-use practices: uncultivated sites and rice–wheat, maize–wheat and sugarcane agro-ecosystems. Uncultivated soils had a higher total C pool than croplands. The soil inorganic C concentrations were in the range of 0.7–1.4 g kg–1 under different land-use practices. Strong correlations were found between TOC and all organic C pools, except water-extractable organic C and mineralisable C. The sensitivity index indicated that soil organic C pools were susceptible to changes in land-use practices. Discriminant function analysis showed that the nine soil variables could distinguish the maize–wheat and rice–wheat systems from uncultivated and sugarcane systems. Finally, we recommend crop rotation practices whereby planting sugarcane replenishes TOC content in soils.


Forests ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1276
Author(s):  
Anna Walkiewicz ◽  
Adrianna Rafalska ◽  
Piotr Bulak ◽  
Andrzej Bieganowski ◽  
Bruce Osborne

Forests contribute strongly to global carbon (C) sequestration and the exchange of greenhouse gases (GHG) between the soil and the atmosphere. Whilst the microbial activity of forest soils is a major determinant of net GHG exchange, this may be modified by the presence of litter through a range of mechanisms. Litter may act as a physical barrier modifying gas exchange, water movement/retention and temperature/irradiance fluctuations; provide a source of nutrients for microbes; enhance any priming effects, and facilitate macro-aggregate formation. Moreover, any effects are influenced by litter quality and regulated by tree species, climatic conditions (rainfall, temperature), and forest management (clear-cutting, fertilization, extensive deforestation). Based on climate change projections, the importance of the litter layer is likely to increase due to an litter increase and changes in quality. Future studies will therefore have to take into account the effects of litter on soil CO2 and CH4 fluxes for various types of forests globally, including the impact of climate change, insect infestation, and shifts in tree species composition, as well as a better understanding of its role in monoterpene production, which requires the integration of microbiological studies conducted on soils in different climatic zones.


2008 ◽  
Vol 84 (1) ◽  
pp. 76-82 ◽  
Author(s):  
Victor J Lieffers ◽  
Glen W Armstrong ◽  
Kenneth J Stadt ◽  
Eckehart H Marenholtz

Regeneration standards in Alberta have developed incrementally over the last 40 years to ensure that cutover areas are regenerated with commercially valuable species that will contribute to timber yield. These standards have been controversial for the boreal mixedwood forest, because they do not appear to be producing forests that are similar in composition and structure to those found naturally. In this paper we discuss several components of the standards that are problematic: the issue of landbase designations that force relatively pure stands of spruce onto the landscape early in stand development compared to natural conditions where spruce establishes below deciduous canopies; the need for the free-to-grow standard, which requires removal of a large proportion of the deciduous trees in these mixedwood forests; and the overall philosophy that stands should be managed to maintain relatively simple composition and canopy structures. Regeneration standards need to be better-linked with forest management planning to allow managers to produce stands of a range of composition and structure. Key words: policy, free-to-grow, competition, forest composition, succession


Forests ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 3 ◽  
Author(s):  
Kobra Maleki ◽  
Mohamadou Alpha Gueye ◽  
Benoit Lafleur ◽  
Alain Leduc ◽  
Yves Bergeron

Natural disturbances, such as fire and insect outbreaks, play important roles in natural forest dynamics, which are characterized over long time scales by changes in stand composition and structure. Individual-based forest simulators could help explain and predict the response of forest ecosystems to different disturbances, silvicultural treatments, or environmental stressors. This study evaluated the ability of the SORTIE-ND simulator to reproduce post-disturbance dynamics of the boreal mixedwoods of eastern Canada. In 1991 and 2009, we sampled all trees (including seedlings and saplings) in 431 (256 m2) plots located in the Lake Duparquet Research and Teaching Forest (western Quebec). These plots were distributed in stands originating from seven wildfires that occurred between 1760 and 1944, and which represented a chronosequence of post-disturbance stand development. We used the 1991 inventory data to parameterize the model, and simulated short- to long-term natural dynamics of post-fire stands in both the absence and presence of a spruce budworm outbreak. We compared short-term simulated stand composition and structure with those observed in 2009 using a chronosequence approach. The model successfully generated the composition and structure of empirical observations. In long-term simulations, species dominance of old-growth forests was not accurately estimated, due to possible differences in stand compositions following wildfires and to differences in stand disturbance histories. Mid- to long-term simulations showed that the secondary disturbance incurred by spruce budworm did not cause substantial changes in early successional stages while setting back the successional dynamics of middle-aged stands and accelerating the dominance of white cedar in late-successional post-fire stands. We conclude that constructing a model with appropriate information regarding stand composition and disturbance history considerably increases the strength and accuracy of the model to reproduce the natural dynamics of post-disturbance boreal mixedwoods.


2013 ◽  
Vol 10 (7) ◽  
pp. 11319-11341
Author(s):  
H. Chen ◽  
W. Zhang ◽  
F. Gilliam ◽  
L. Liu ◽  
J. Huang ◽  
...  

Abstract. Urbanization is accelerating globally, causing a variety of environmental changes such as increases in air temperature, precipitation, atmospheric CO2, and nitrogen (N) deposition. However, effects of these changes on forest soil carbon (C) sequestration remain largely unclear. Here we used urban-to-rural environmental gradients in Guangdong Province, southern China, to address the potential effects of these environmental changes on soil C sequestration in Pinus massoniana forests. In contrast with our expectations and earlier observations, soil C content in urban sites was significantly lower than those in suburban and rural sites. Lower soil C pools in urban sites were correlated with a significant decrease in fine root biomass and a potential increase in soil organic C decomposition. Variation of soil C pools was also a function of change in soil C fractions. Heavy fraction C content in urban sites was significantly lower than those in suburban and rural sites. By contrast, light fraction C content did not vary significantly along the urban-to-rural gradient. Our results suggest that urbanization-induced environmental changes may have negative effect on forest soil C.


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