Soil respiration variation along an altitudinal gradient in the Italian Alps: Disentangling forest structure and temperature effects

On the mountains, along an elevation gradient, we generally observe an ample variation in temperature, with the associated difference in vegetation structure and composition and soil properties. With the aim of quantifying the relative importance of temperature, vegetation and edaphic properties on soil respiration (SR), we investigated changes in SR along an elevation gradient (404 to 2101 m a.s.l) in the southern slopes of the Alps in Northern Italy. We also analysed soil physicochemical properties, including soil organic carbon (SOC) and nitrogen (N) stocks, fine root C and N, litter C and N, soil bulk densities and soil pH at five forest sites, and also stand structural properties, including vegetation height, age and basal area. Our results indicated that SR rates increased with temperature in all sites, and 55–76% of SR variability was explained by temperature. Annual cumulative SR, ranging between 0.65–1.40 kg C m-2 yr-1, decreased along the elevation gradient, while temperature sensitivity (Q10) of SR increased with elevation. However, a high SR rate (1.27 kg C m-2 yr-1) and low Q10 were recorded in the mature conifer forest stand at 1731 m a.s.l., characterized by an uneven-aged structure and high dominant tree height, resulting in a nonlinear relationship between elevation and temperature. Reference SR at 10°C (SRref) was unrelated to elevation, but was related to tree height. A significant negative linear relationship was found between bulk density and elevation. Conversely, SOC, root C and N stock, pH, and litter mass were best fitted by nonlinear relationships with elevation. However, these parameters were not significantly correlated with SR when the effect of temperature was removed (SRref). These results demonstrate that the main factor affecting SR in forest ecosystems along this Alpine elevation gradient is temperature, but its regulating role can be strongly influenced by site biological characteristics, particularly vegetation type and structure, affecting litter quality and microclimate. This study also confirms that high elevation sites are rich in SOC and more sensitive to climate change, being prone to high C losses as CO2. Furthermore, our data indicate a positive relationship between Q10 and dominant tree height, suggesting that mature forest ecosystems characterized by an uneven-age structure, high SRref and moderate Q10, may be more resilient.

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Soil respiration variation along an altitudinal gradient in Italian Alps: Disentangling forest structure and temperature effects

10.1101/2021.02.17.431600 ◽

2021 ◽

Author(s):

Aysan Badraghi ◽

Maurizio Ventura ◽

Andrea Polo ◽

Luigimaria Borruso ◽

Leonardo Montagnani

Keyword(s):

Soil Respiration ◽

Forest Structure ◽

Forest Ecosystems ◽

Vegetation Type ◽

Complex Structure ◽

Elevation Gradient ◽

Negative Relationship ◽

Effect Of Temperature ◽

Conifer Forest ◽

C And N

AbstractTo understand the main determinants of soil respiration (SR), we investigated the changes of soil respiration and soil physicochemical properties, including soil carbon (C) and nitrogen (N), root C and N, litter C and N, soil bulk densities and soil pH at five forest sites, along an elevation/temperature gradient (404 to 2101 m a.s.l) in Northern Italy, where confounding factors such as aspect and soil parent material are minimized, but an ample variation in forest structure and composition is present. Our result indicated that SR rates increased with temperature in all sites, and about 55% - 76% of SR was explained by temperature. Annual cumulative SR, ranging between 0.65 and 1.40 kg C m-2 yr-1, declined along the elevation gradient, while temperature sensitivity (Q10) of SR increased with elevation. However, a high SR rate (1.27 kg C m-2 yr-1) and low Q10 were recorded in the old conifer forest stand at 1731 m a.s.l., characterized by a complex structure and high productivity, introducing nonlinearity in the relations with elevation and temperature. Reference SR at the temperature of 10°C (SRref) was not related to elevation. A significant linear negative relationship was found for bulk density with elevation. On the contrary, soil C, soil N, root C, root N, pH and litter mass were better fitted by nonlinear relations with elevation. However, it was not possible to confirm a significant correlation of SR with these parameters once the effect of temperature has been removed (SRref). These results show how the main factor affecting SR in forest ecosystems along this Alpine elevation gradient is temperature, but its regulating role can be strongly influenced by site biological characteristics, particularly vegetation type and structure. This study also confirms that high elevation sites are rich in C stored in the soil and also more sensitive to climate change, being prone to high carbon losses as CO2. Conversely, forest ecosystems with a complex structure, with high SRref and moderate Q10, can be more resilient.

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Variations of belowground C and N cycling between arbuscular mycorrhizal and ectomycorrhizal forests across China

Soil Research ◽

10.1071/sr19377 ◽

2020 ◽

Vol 58 (5) ◽

pp. 441 ◽

Cited By ~ 1

Author(s):

Jiwei Li ◽

Zhouping Shangguan ◽

Lei Deng

Keyword(s):

Soil Respiration ◽

Forest Ecosystems ◽

Arbuscular Mycorrhizal ◽

N Cycling ◽

Microbial Biomass C ◽

N Cycle ◽

Positive Effects ◽

Litter Input ◽

C And N ◽

C And N Cycling

Forests associating with arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi may have distinct belowground carbon (C) and nitrogen (N) cycle processes. However, there are little available data providing evidence for the effects of trees associating with mycorrhizal type on belowground C and N cycling in forest ecosystems in China. Here, we collected a database of 26 variables related to belowground C and N cycling from 207 studies covering 209 sampling sites in China, to better understand the variations in belowground C and N cycling between the two mycorrhizal types in forest ecosystems along a climatic gradient. The AM forests had significantly lower soil total C and N contents, and soil microbial biomass C and N, than ECM forests, probably due to differences in litter quality (N and C/N) between AM and ECM forest types. In contrast, AM forests had significantly higher litter input, litter decomposition and soil respiration than ECM forests. Temperature and precipitation had significant positive effects on litter input and decomposition, soil total C and N contents, and soil respiration in AM and ECM forests. Overall, our results indicated that mycorrhizal type strongly affected belowground C and N cycle processes in forest ecosystems. Moreover, AM forests are likely more sensitive and ECM forests have a greater ability to adapt to global climate change.

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Elevation Gradient Altered Soil C, N, and P Stoichiometry of Pinus taiwanensis Forest on Daiyun Mountain

Forests ◽

10.3390/f10121089 ◽

2019 ◽

Vol 10 (12) ◽

pp. 1089

Author(s):

Lan Jiang ◽

Zhongsheng He ◽

Jinfu Liu ◽

Cong Xing ◽

Xinguang Gu ◽

...

Keyword(s):

Elevation Gradient ◽

C:N Ratio ◽

Phosphate Fertilizer ◽

High Elevation ◽

Driving Factors ◽

Slope Position ◽

Elevation Gradients ◽

Soil C ◽

Soil P ◽

C And N

Researches focused on soil carbon (C), nitrogen (N), and phosphorus (P) content and the stoichiometry characteristics along elevation gradients are important for effective management of forest ecosystems. Taking the soil of different elevations from 900 to 1700 m on Daiyun Mountain as the object, the elevation distribution of total C, N, and P in soil and their stoichiometry characteristics were studied. Also, the driving factors resulting in the spatial heterogeneity of soil stoichiometry are presented. The results show the following: (1) The average soil C and N content was 53.03 g·kg−1 and 3.82 g·kg−1, respectively. The content of C and N at high elevation was higher than that of at low elevation. Soil phosphorus fluctuated with elevation. (2) With increasing elevation, soil C:N ratio increased initially to 17.40 at elevation between 900–1000 m, and then decreased to 12.02 at elevation 1600 m. The changing trends of C:P and N:P were similar, and they all fluctuated with elevation. (3) Elevation, soil bulk density, and soil temperature were the main factors influencing the variation of soil C, N, and C:N. Soil pH and slope position were the driving factors for soil P, C:P, and N:P. The soil is rich in C and N, and has less total phosphorus on Daiyun Mountain. Raising the level of phosphate fertilizer appropriately can help to improve soil fertility and promote plant growth as well. In light of this information, in the near future, it will be necessary to conduct separation management of C, N, and P with regular monitoring systems to maintain favorable conditions for soil.

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Decoupling litter respiration from whole-soil respiration along an elevation gradient in a Rocky Mountain mixed-conifer forest

Canadian Journal of Forest Research ◽

10.1139/cjfr-2013-0334 ◽

2014 ◽

Vol 44 (5) ◽

pp. 432-440 ◽

Cited By ~ 11

Author(s):

Erin M. Berryman ◽

John D. Marshall ◽

Kathleen Kavanagh

Keyword(s):

Soil Respiration ◽

Elevation Gradient ◽

Rocky Mountain ◽

Mean Annual Temperature ◽

Conifer Forest ◽

Atmospheric Humidity ◽

Positive Interaction ◽

Mixed Conifer Forest ◽

Litter Respiration ◽

Northern Idaho

Litter respiration (RL) represents a significant portion of whole-soil respiration (RS) in forests, yet climatic correlations with RL have seldom been examined. Because RL is reduced at low humidities and RS is reduced at low temperatures, these components may show divergent trends with elevation in western North American forests. Using a litter-removal experiment along a forested 750 m elevation gradient in the Rocky Mountains of northern Idaho, USA, we measured RS on soils from which litter had been removed (RNL) and, by difference, RL. Mean RL represented 16% (SE = 2%) of mean RS from July through October of 2007 and 2008. RS was highest at warmer times and sites, and was not suppressed by low soil moisture. In contrast, RL was highest at cooler times, when humidity and gravimetric litter water content were highest. RL was highest at mid-elevations, representing neither the warmest nor wettest sites. Sixty-three percent of variability in site RL was explained by both mean annual temperature (MAT) and mean annual relative humidity (MARH), including a positive interaction effect between MAT and MARH. Our results imply that the equilibration of litter with atmospheric humidity is an important control over litter respiration rates.

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Effects of long-term nitrogen addition on soil respiration and its components in a boreal forest

10.21203/rs.3.rs-57463/v1 ◽

2020 ◽

Author(s):

Guancheng Liu ◽

Tong Liu ◽

Guoyong Yan ◽

Lei Wang ◽

Xiaochun Wang ◽

...

Keyword(s):

Soil Respiration ◽

Boreal Forest ◽

Forest Ecosystems ◽

Nitrogen Addition ◽

N Deposition ◽

Microbial Biomass C ◽

N Addition ◽

Soil C ◽

C And N

Abstract Background Atmospheric nitrogen (N) deposition in boreal forest ecosystems increased gradually with the development of industry and agriculture, but the effects of N input on soil CO2 fluxes in these ecosystems were rarely reported in previous studies. To evaluate the effect of N addition on soil respiration is of great significance for understanding the distribution of soil carbon (C) on the N gradient in forest ecosystems.Results In this study, four treatment levels of N addition (0, 25, 50, 75 kg N ha− 1 yr− 1) were applied to natural Larix gmelinii forest in Greater Khingan Mountains of northeast China. We focused mainly on the dynamics of soil respiration (Rs), heterotrophic respiration (Rh), autotrophic respiration (Ra), microbial biomass C and N (MBC and MBN) and fine root biomass (FRB) in a growing season. We found that low N addition significant increased Rs, Rh and Ra, but with the increase of N addition, the promotion effect was gradually weakened. Medium N increased the temperature sensitivity (Q10) of Rs and Rh components, while medium N and high N significantly reduced the Q10 of Ra. Ra was positively correlated with FRB; Rh was positively correlated with soil MBC and MBN; and RS was probably driven by Ra from May to July, while by Rh in August and September.Conclusions Long-term N addition alleviated microbial N limitation, promoted soil respiration and accelerated soil C and N cycle in boreal forest ecosystems.

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Recent Megafires Provide a Tipping Point for Desertification of Conifer Ecosystems

10.5772/intechopen.101595 ◽

2022 ◽

Author(s):

Daniel G. Neary

Keyword(s):

Forest Ecosystems ◽

Vegetation Type ◽

Fire Suppression ◽

Coniferous Forest ◽

Thunderstorm Activity ◽

Conifer Forests ◽

Conifer Forest ◽

Type Conversion ◽

Population Demographics ◽

Severe Erosion

Recent megafires and gigafires are contributing to the desertification of conifer forest ecosystems due to their size and severity. Megafires have been increasing in their frequency in the past two decades of the 21st century. They are classed as such because of being 40,469 to 404,694 ha in size, having high complexity, resisting suppression, and producing desertification due to erosion and vegetation type conversion. Increasingly, gigafires (>404,694 ha) are impacting coniferous forest ecosystems. These were once thought of as only pre-20th century phenomena when fire suppression was in its infancy. Climate change is an insidious inciting factor in large wildfire occurrences. Fire seasons are longer, drier, hotter, and windier due to changes in basic meteorology. Conifer forests have accumulated high fuel loads in the 20th and 21st centuries. Ignition sources in conifer forests have increased as well due to human activities, economic development, and population demographics. Natural ignitions from lightning are increasing as a result of greater severe thunderstorm activity. Drought has predisposed these forests to easy fire ignition and spread. Wildfires are more likely to produce vegetation shifts from conifers to scrublands or grasslands, especially when wildfires occur with higher frequency and severity. Severe erosion after megafires has the collateral damage of reducing conifer resilience and sustainability.

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Soil Respiration Variation among Four Tree Species at Young Afforested Sites under the Influence of Frequent Typhoon Occurrences

Forests ◽

10.3390/f12060787 ◽

2021 ◽

Vol 12 (6) ◽

pp. 787

Author(s):

Po-Neng Chiang ◽

Jui-Chu Yu ◽

Yen-Jen Lai

Keyword(s):

Soil Respiration ◽

Aboveground Biomass ◽

Tree Species ◽

Forest Ecosystems ◽

Tree Height ◽

Effective Solution ◽

Monsoon Climate ◽

Soil C ◽

Southern Taiwan ◽

The Tropics

Afforestation is an effective solution for restoring forest ecosystems and mitigating climate change in the tropics. In this study, we analyzed the soil respiration (Rs) at four afforested sites with different tree species exposed to a monsoon climate with frequent typhoon occurrences in southern Taiwan. The aim of this study is to examine (1) the distinct seasonal variation that strongly affects the Rs among four tree species at afforested sites, (2) the patterns of Rs that differ among the four species at the afforested sites, and (3) the influence of typhoons on forest structure and consequently the degree of Rs. The annual mean Rs among the four tree species at the afforested sites in the pretyphoon disturbance year was approximately 7.65 t C ha−1, with the post-typhoon year having an annual mean Rs of approximately 9.13 t C ha−1. Our results clearly show Rs variations in the four tree species at the young afforested sites under the influence of typhoon disturbances. The high seasonal variations in Rs were controlled by soil temperature and soil moisture. The different tree species also led to variations in litterfall production and consequently influenced Rs variation. Forest structures, such as aboveground biomass and consequently the degree of Rs, were disturbed by severe typhoon impacts in 2016, resulting in high aboveground biomass with tree height losses and litterfall accumulation. Furthermore, Rs increased immediately after litterfall input to the soil, and the addition effect of litter and the soil C release occurred throughout the year after typhoon disturbances. Our results contribute to understanding impact of typhoon disturbances on the degree of Rs at tropical afforested sites.

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Spatial distribution patterns of soil total phosphorus influenced by climatic factors in China’s forest ecosystems

Scientific Reports ◽

10.1038/s41598-021-84166-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jie Zhu ◽

Anchi Wu ◽

Guoyi Zhou

Keyword(s):

Spatial Distribution ◽

Forest Ecosystems ◽

Climatic Factors ◽

Critical Role ◽

Effect Of Temperature ◽

P Concentration ◽

Single Effect ◽

The Impact ◽

P Distribution ◽

Total P

AbstractPhosphorus (P) is an important element in terrestrial ecosystems and plays a critical role in soil quality and ecosystem productivity. Soil total P distributions have undergone large spatial changes as a result of centuries of climate change. It is necessary to study the characteristics of the horizontal and vertical distributions of soil total P and its influencing factors. In particular, the influence of climatic factors on the spatial distribution of soil total P in China’s forest ecosystems remain relatively unknown. Here, we conducted an intensive field investigation in different forest ecosystems in China to assess the effect of climatic factors on soil total P concentration and distribution. The results showed that soil total P concentration significantly decreased with increasing soil depth. The spatial distribution of soil total P increased with increasing latitude and elevation gradient but decreased with increasing longitude gradient. Random forest models and linear regression analyses showed that the explanation rate of bioclimatic factors and their relationship with soil total P concentration gradually decreased with increasing soil depths. Variance partitioning analysis demonstrated that the most important factor affecting soil total P distribution was the combined effect of temperature and precipitation factor, and the single effect of temperature factors had a higher explanation rate compare with the single effect of precipitation factors. This work provides a new farmework for the geographic distribution pattern of soil total P and the impact of climate variability on P distribution in forest ecosystems.

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Distribution and altitudinal patterns of carbon and nitrogen storage in various forest ecosystems in the central Yunnan Plateau, China

Scientific Reports ◽

10.1038/s41598-021-85710-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jianqiang Li ◽

Qibo Chen ◽

Zhuang Li ◽

Bangxiao Peng ◽

Jianlong Zhang ◽

...

Keyword(s):

Forest Ecosystems ◽

Sustainable Forest Management ◽

Carbon And Nitrogen ◽

Pinus Yunnanensis ◽

Yunnan Plateau ◽

Baseline Information ◽

C And N ◽

Quercus Semecarpifolia ◽

Management Policies

AbstractThe carbon (C) pool in forest ecosystems plays a long-term and sustained role in mitigating the impacts of global warming, and the sequestration of C is closely linked to the nitrogen (N) cycle. Accurate estimates C and N storage (SC, SN) of forest can improve our understanding of C and N cycles and help develop sustainable forest management policies in the content of climate change. In this study, the SC and SN of various forest ecosystems dominated respectively by Castanopsis carlesii and Lithocarpus mairei (EB), Pinus yunnanensis (PY), Pinus armandii (PA), Keteleeria evelyniana (KE), and Quercus semecarpifolia (QS) in the central Yunnan Plateau of China, were estimated on the basis of a field inventory to determine the distribution and altitudinal patterns of SC and SN among various forest ecosystems. The results showed that (1) the forest SC ranged from 179.58 ± 20.57 t hm−1 in QS to 365.89 ± 35.03 t hm−1 in EB. Soil, living biomass and litter contributed an average of 64.73%, 31.72% and 2.86% to forest SC, respectively; (2) the forest SN ranged from 4.47 ± 0.94 t ha−1 in PY to 8.91 ± 1.83 t ha−1 in PA. Soil, plants and litter contributed an average of 86.88%, 10.27% and 2.85% to forest SN, respectively; (3) the forest SC and SN decreased apparently with increasing altitude. The result demonstrates that changes in forest types can strongly affect the forest SC and SN. This study provides baseline information for forestland managers regarding forest resource utilization and C management.

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Comparison of carbon and nitrogen storage in mineral soils of graminoid and shrub tundra sites, western Greenland

Arctic Science ◽

10.1139/as-2015-0023 ◽

2016 ◽

Vol 2 (4) ◽

pp. 165-182 ◽

Cited By ~ 5

Author(s):

Chelsea L. Petrenko ◽

Julia Bradley-Cook ◽

Emily M. Lacroix ◽

Andrew J. Friedland ◽

Ross A. Virginia

Keyword(s):

Vegetation Type ◽

Mineral Soil ◽

Biotic Interactions ◽

The Arctic ◽

Soil C ◽

N Storage ◽

C Storage ◽

Arctic Soils ◽

C Pools ◽

C And N

Shrub species are expanding across the Arctic in response to climate change and biotic interactions. Changes in belowground carbon (C) and nitrogen (N) storage are of global importance because Arctic soils store approximately half of global soil C. We collected 10 (60 cm) soil cores each from graminoid- and shrub-dominated soils in western Greenland and determined soil texture, pH, C and N pools, and C:N ratios by depth for the mineral soil. To investigate the relative chemical stability of soil C between vegetation types, we employed a novel sequential extraction method for measuring organo-mineral C pools of increasing bond strength. We found that (i) mineral soil C and N storage was significantly greater under graminoids than shrubs (29.0 ± 1.8 versus 22.5 ± 3.0 kg·C·m−2 and 1.9 ± .12 versus 1.4 ± 1.9 kg·N·m−2), (ii) chemical mechanisms of C storage in the organo-mineral soil fraction did not differ between graminoid and shrub soils, and (iii) weak adsorption to mineral surfaces accounted for 40%–60% of C storage in organo-mineral fractions — a pool that is relatively sensitive to environmental disturbance. Differences in these C pools suggest that rates of C accumulation and retention differ by vegetation type, which could have implications for predicting future soil C pool storage.

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