ForBioFunCtioN: Forest soil carbon and the effects of climate change and forest management

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

<p>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.</p><p>In the face of climate change, the ForBioFunCtioN project is dedicated to investigating the response of boreal forest soil CO<sub>2</sub> and CH<sub>4</sub> fluxes to experimentally increased temperatures and increased precipitation – climatic changes in line with projections over Norway – 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 (©LI-COR Biosciences). The presentation will show the experimental setup and first measurements from the large-scale experiment.</p>

2013 ◽  
Vol 43 (5) ◽  
pp. 469-479 ◽  
Author(s):  
Weifeng Wang ◽  
Changhui Peng ◽  
Daniel D. Kneeshaw ◽  
Guy R. Larocque ◽  
Xiangdong Lei ◽  
...  

Climate change and its potential effects on ecosystems justify the need to implement forest management strategies that increase carbon (C) sequestration. A process-based model, TRIPLEX-Management, was used to investigate how to increase C sequestration within managed jack pine (Pinus banksiana Lamb.) forests. The simulations included a constant climate scenario and two climate change scenarios generated from the Coupled Global Climate Model (CGCM 3.1). A total of 36 forest management scenarios (a control where no forest management occurred, five varied rotation length harvesting-only regimes, and combinations of six thinning regimes and five rotation lengths) were simulated under each climate scenario for nine sites characterized by stocking levels from 0.3 to 0.7. A significant increase in C sequestration was generated under the climate change scenarios compared with those under constant climate. Mean annual net ecosystem productivity (NEP) varied with rotation length, but was not changed by precommercial thinning. Future studies should consider life cycle analysis of harvested wood products as in this study they were assumed to be a permanent C sink. Climate warming might enhance limited positive effects of forest thinning on C sequestration. Shortening rotation length from 70–80 years to 50 years might enhance NEP, increase wood production, and decrease the risk of climate change impacts on jack pine forests.


Author(s):  
Meng Na ◽  
Xiaoyang Sun ◽  
Yandong Zhang ◽  
Zhihu Sun ◽  
Johannes Rousk

AbstractSoil carbon (C) reservoirs held in forests play a significant role in the global C cycle. However, harvesting natural forests tend to lead to soil C loss, which can be countered by the establishment of plantations after clear cutting. Therefore, there is a need to determine how forest management can affect soil C sequestration. The management of stand density could provide an effective tool to control soil C sequestration, yet how stand density influences soil C remains an open question. To address this question, we investigated soil C storage in 8-year pure hybrid larch (Larix spp.) plantations with three densities (2000 trees ha−1, 3300 trees ha−1 and 4400 trees ha−1), established following the harvesting of secondary mixed natural forest. We found that soil C storage increased with higher tree density, which mainly correlated with increases of dissolved organic C as well as litter and root C input. In addition, soil respiration decreased with higher tree density during the most productive periods of warm and moist conditions. The reduced SOM decomposition suggested by lowered respiration was also corroborated with reduced levels of plant litter decomposition. The stimulated inputs and reduced exports of C from the forest floor resulted in a 40% higher soil C stock in high- compared to low-density forests within 8 years after plantation, providing effective advice for forest management to promote soil C sequestration in ecosystems.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Faming Wang ◽  
Xiaoliang Lu ◽  
Christian J. Sanders ◽  
Jianwu Tang

AbstractCoastal wetlands are large reservoirs of soil carbon (C). However, the annual C accumulation rates contributing to the C storage in these systems have yet to be spatially estimated on a large scale. We synthesized C accumulation rate (CAR) in tidal wetlands of the conterminous United States (US), upscaled the CAR to national scale, and predicted trends based on climate change scenarios. Here, we show that the mean CAR is 161.8 ± 6 g Cm−2 yr−1, and the conterminous US tidal wetlands sequestrate 4.2–5.0 Tg C yr−1. Relative sea level rise (RSLR) largely regulates the CAR. The tidal wetland CAR is projected to increase in this century and continue their C sequestration capacity in all climate change scenarios, suggesting a strong resilience to sea level rise. These results serve as a baseline assessment of C accumulation in tidal wetlands of US, and indicate a significant C sink throughout this century.


Author(s):  
C. D. Koven ◽  
E. A. G. Schuur ◽  
C. Schädel ◽  
T. J. Bohn ◽  
E. J. Burke ◽  
...  

We present an approach to estimate the feedback from large-scale thawing of permafrost soils using a simplified, data-constrained model that combines three elements: soil carbon (C) maps and profiles to identify the distribution and type of C in permafrost soils; incubation experiments to quantify the rates of C lost after thaw; and models of soil thermal dynamics in response to climate warming. We call the approach the Permafrost Carbon Network Incubation–Panarctic Thermal scaling approach (PInc-PanTher). The approach assumes that C stocks do not decompose at all when frozen, but once thawed follow set decomposition trajectories as a function of soil temperature. The trajectories are determined according to a three-pool decomposition model fitted to incubation data using parameters specific to soil horizon types. We calculate litterfall C inputs required to maintain steady-state C balance for the current climate, and hold those inputs constant. Soil temperatures are taken from the soil thermal modules of ecosystem model simulations forced by a common set of future climate change anomalies under two warming scenarios over the period 2010 to 2100. Under a medium warming scenario (RCP4.5), the approach projects permafrost soil C losses of 12.2–33.4 Pg C; under a high warming scenario (RCP8.5), the approach projects C losses of 27.9–112.6 Pg C. Projected C losses are roughly linearly proportional to global temperature changes across the two scenarios. These results indicate a global sensitivity of frozen soil C to climate change ( γ sensitivity) of −14 to −19 Pg C °C −1 on a 100 year time scale. For CH 4 emissions, our approach assumes a fixed saturated area and that increases in CH 4 emissions are related to increased heterotrophic respiration in anoxic soil, yielding CH 4 emission increases of 7% and 35% for the RCP4.5 and RCP8.5 scenarios, respectively, which add an additional greenhouse gas forcing of approximately 10–18%. The simplified approach presented here neglects many important processes that may amplify or mitigate C release from permafrost soils, but serves as a data-constrained estimate on the forced, large-scale permafrost C response to warming.


2020 ◽  
Author(s):  
Virginia Sánchez-Navarro ◽  
Mariano Marcos-Pérez ◽  
Raúl Zornoza

<p><strong>Legume crops have been proposed as a way of reducing greenhouse gas (GHG) emissions because both, their rhizosphere behaviour and their ability to fix atmospheric N reducing the need of external N fertilizer. Moreover, the establishment of organic agriculture has been proposed as a sustainable strategy to enhance the delivery of ecosystem services, including mitigation of climate change by decreases in GHG emissions and increases in soil C sequestration. The aim of this study was to assess the effect of the association between cowpea (Vigna unguiculata L.) and melon (Cucumis melo L.) growing in different </strong>intercropping patterns <strong>on soil CO<sub>2</sub> and N<sub>2</sub>O emissions compared to cowpea and melon monocultures </strong><strong>under organic management as a possible strategy for climate change mitigation. Soil </strong><strong>CO<sub>2</sub> and N<sub>2</sub>O</strong><strong> emissions were weekly measured in melon and cowpea rows using the dynamic chamber method during one cropping cycle in 2019. Results indicated that melon growing as monoculture was related to increases in </strong> <strong>O cumulative emissions (0.431 g m<sup>-2</sup>) compared to the average of the rest of treatments (0.036 g m<sup>-2</sup>). Cowpea growing as monoculture was related to decreases in </strong><strong>CO<sub>2</sub></strong> <strong>cumulative emissions (390 g m<sup>-2</sup>) compared with the other treatments (512 g m<sup>-2 </sup>average). However, N<sub>2</sub>O and </strong><strong>CO<sub>2</sub></strong><strong> emission patterns did not directly follow soil moisture patterns in the experimental period, with no significant correlations. Finally there were no significant differences among intercropping treatments with regard to NO<sub>2</sub> and </strong><strong>CO<sub>2 </sub></strong><strong>emissions. Further measurements are needed to monitor the evolution of GHG emissions under these cropping systems and confirm the trend observed</strong>.</p>


2010 ◽  
Vol 86 (3) ◽  
pp. 354-364 ◽  
Author(s):  
Henrik Hartmann ◽  
Gaëtan Daoust ◽  
Brigitte Bigué

Terrestrial biodiversity is closely linked to forest ecosystems but anthropogenic reductions in forest cover and changes in forest structure and composition jeopardize their biodiversity. Several forest species are threatened because of reduced habitat quality and fragmentation or even habitat loss as a result of forest management activities. In response to this threat, integrated forest management (IFM) was developed in the early 1990s and has been applied over large spatial scales ever since. While IFM seeks to satisfy both human resource demands and ecosystem integrity, the whole forest matrix is affected and this may also have negative impacts on biodiversity. The concept of forest zoning (e.g., Triad) avoids these issues by physically separating land uses from each other. The zoning approach has been developed in the same period as IFM, but there are still very few examples of large-scale applications. This may be because its distinctiveness from IFM may not always seem clear and because forest zoning is not easily implemented. Here we explain these differences and show that IFM and the zoning approach are indeed different management paradigms. We advocate the use of high-yield plantations within the zoning paradigm as a means for biodiversity conservation and review the literature (with an emphasis on the northern hemisphere and on plantation forestry within a land-zoning approach) on impacts of forest management activities on biodiversity. Furthermore, we give advice on issues that require consideration when implementing forest zoning at both the stand and the landscape levels. We recommend several small changes in design and management of forest plantations as a means to significantly increase their biodiversity value. We conclude that while forest zoning seems an adequate strategy for the Canadian forestry sector, a shift in paradigm must carry over to policy-makers and legislation if this approach is to succeed. Key words: biodiversity, landbase zoning, forest management, intensive silviculture, plantation forests


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.


2020 ◽  
Author(s):  
Hongxing He ◽  
Per-Erik Jansson ◽  
Annemieke Gärdenäs

Abstract. This study presents the integration of the phosphorus (P) cycle into CoupModel (Coup-CNP). The extended Coup-CNP enables simulations of coupled carbon (C), nitrogen (N) and P dynamics for terrestrial ecosystems which explicitly consider mycorrhizal interactions. The model was evaluated against observed forest growth and measured leaf C/P, C/N and N/P ratios in four managed forest regions in Sweden. The four regions form a climatic and fertility gradient from 64° N in the North to 56° N in South Sweden with the mean annual temperature varying between 0.7–7.1 °C and the soil C/N and C/P ratios between 19.8–31.5 and 425–633, respectively. The growth of the southern forests was found to be P-limited, with harvested biomass representing the largest P loss over the studied rotation period. The simulated P budgets revealed that southern forests are losing P while northern forests are close to a steady state in P availability. Mycorrhizal fungi account for half of the total plant P uptake across all four regions, which highlights the importance of fungal-tree interactions in Swedish forests. Sensitivity analysis results demonstrated that the highest forest growth occurs at a soil N/P ratio of 15 to 20. A soil N/P ratio above 15–20 resulted in decreased soil C sequestration and total P leaching, but significantly increased N leaching. The development and evaluation of the new Coup-CNP model demonstrate that P fluxes need to be further considered in studies of how climate change will influence C turnover and ecosystem responses. We conclude that the potential P-limitation of terrestrial ecosystems highlights the need of a proper consideration of the P cycle in biogeochemical models. The inclusion of the P cycle is necessary in order to make models reliable tools for assessing long-term impacts of climate change and N deposition on C sequestration and N leaching.


2017 ◽  
Vol 17 (19) ◽  
pp. 11849-11859 ◽  
Author(s):  
Guocheng Wang ◽  
Wen Zhang ◽  
Wenjuan Sun ◽  
Tingting Li ◽  
Pengfei Han

Abstract. Changes in the soil organic carbon (SOC) stock are determined by the balance between the carbon input from organic materials and the output from the decomposition of soil C. The fate of SOC in cropland soils plays a significant role in both sustainable agricultural production and climate change mitigation. The spatiotemporal changes of soil organic carbon in croplands in response to different carbon (C) input management and environmental conditions across the main global cereal systems were studied using a modeling approach. We also identified the key variables that drive SOC changes at a high spatial resolution (0.1°  ×  0.1°) and over a long timescale (54 years from 1961 to 2014). A widely used soil C turnover model (RothC) and state-of-the-art databases of soil and climate variables were used in the present study. The model simulations suggested that, on a global average, the cropland SOC density increased at annual rates of 0.22, 0.45 and 0.69 Mg C ha−1 yr−1 under crop residue retention rates of 30, 60 and 90 %, respectively. Increasing the quantity of C input could enhance soil C sequestration or reduce the rate of soil C loss, depending largely on the local soil and climate conditions. Spatially, under a specific crop residue retention rate, relatively higher soil C sinks were found across the central parts of the USA, western Europe, and the northern regions of China. Relatively smaller soil C sinks occurred in the high-latitude regions of both the Northern and Southern hemispheres, and SOC decreased across the equatorial zones of Asia, Africa and America. We found that SOC change was significantly influenced by the crop residue retention rate (linearly positive) and the edaphic variable of initial SOC content (linearly negative). Temperature had weak negative effects, and precipitation had significantly negative impacts on SOC changes. The results can help guide carbon input management practices to effectively mitigate climate change through soil C sequestration in croplands on a global scale.


2005 ◽  
Vol 81 (5) ◽  
pp. 675-682 ◽  
Author(s):  
E.H. (Ted) Hogg ◽  
Pierre Y Bernier

From a climate change perspective, much of the recent international focus on forests has been on their role in taking up carbon dioxide (CO2) from the atmosphere. The question of climate change impacts on forest productivity is also emerging as a critical issue, especially in drought-prone regions such as the western Canadian interior. Because of the complexity of interacting factors, there is uncertainty even in predicting the direction of change in the productivity of Canada's forests as a whole over the next century. In the most climatically vulnerable regions, however, successful adaptation may require more innovative approaches to forest management, coupled with an enhanced capacity for early detection of large-scale changes in forest productivity, dieback and regeneration. Key words: climate change, boreal forest, productivity, drought, impacts, adaptation


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