Belowground Carbon Flux in Forests: Carbon Emission, Storage and Beyond

Dear Colleagues,

Global soil carbon (C) research started in the early twentieth century with an initial focus on soil organic matter dynamics, the nutrient cycle, and soil–plant interactions. Nutrients in soil, particularly the nitrogen cycle, remained a dominant topic in the field for several decades. However, soil C research related to climate change gathered momentum after the adoption of the Kyoto Protocol (1992), a comprehensive reporting framework on soil C stock changes, and the commitments of different nations to reduce their net greenhouse gas emissions. Enormous amounts of research have been devoted to belowground C flux and processes, which has led to the recognition of soil as a potential sink for elevated atmospheric C through photosynthetic fixation in plants. Forest ecosystems play a major role in these nature-based C-capture processes. C is transferred to the soil system via root activities and litter decomposition, and its subsequent destiny is either to become stable soil organic matter or escape to the atmosphere through soil respiration (autotrophic and/or heterotrophic). Attempts to increase soil’s C sequestration potential have led to significant attention being paid to the mechanisms behind the formation and stability of C in soil organic matter. Connected to this, a paradigm shift (2011) in soil organic matter research occurred with the discovery that organo-mineral associations are the major mechanism behind the persistence of C in soil rather than C’s stability being due to the inherent chemical recalcitrance of humic substances. Currently, we understand the possible fates of sequestrated soil organic carbon to be the following: (1) long-term storage in the soil, mostly through organo-mineral associations; (2) respired back into the atmosphere after being mineralized by favourable microbes in the presence of fresh C (i.e., the priming effect); and (3) lost through the leaching of dissolved organic matter (DOM) into surface or subsurface aquatic systems.  

Although our mechanistic understanding of these three processes (the mineral association of C, microbial priming of stored old C, and leaching of DOM) is well documented, a substantial gap in our knowledge exists in terms of the responses of these C-stability-related processes to changing climate, plant and soil variables.

This Special Issue aims to publish empirical evidence on how biotic and abiotic variables influence the storage, long-term stability, and instability of sequestrated C in forest soils.

In this Special Issue, original research articles and reviews are welcome. Their research areas may include (but are not limited to) the following:

• Soil carbon sequestration and storage mechanisms;
• Decomposition processes and their role in carbon release;
• Root respiration and its contribution to carbon flux;
• The influence of soil microbial activity on carbon cycling;
• Role of root–microbe symbiosis in carbon exchange;
• The effect of edaphic factors on belowground carbon flux;
• How plant species composition and root traits impact carbon dynamics;
• The measurement and modelling of belowground carbon flux;
• Impact of disturbance on belowground carbon.

We look forward to receiving your contributions.

Dr. Iftekhar Uddin Ahmed
Prof. Dr. Jaeseok Lee
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Forests is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• soil C storage
• organo-mineral associations
• organic C priming
• dissolved organic matter (DOM)
• tree species identity
• fine root biomass
• root exudates
• microbial decay
• clay minerals
• soil respiration