scholarly journals Effect of ablation rings and soil temperature on 3-year spring CO<sub>2</sub> efflux along the Dalton Highway, Alaska

2014 ◽  
Vol 11 (23) ◽  
pp. 6539-6552 ◽  
Author(s):  
Y. Kim
Keyword(s):  
Climate Change ◽  
Boreal Forest ◽  
Soil Temperature ◽  
Co2 Emissions ◽  
White Spruce ◽  
Co2 Efflux ◽  
Spruce Forest ◽  
Carbon Budgets ◽  
Forest Sites ◽  
Annual Carbon

Abstract. Winter and spring soil CO2 efflux measurements represent a significant component in the assessment of annual carbon budgets of tundra and boreal forest ecosystems, reflecting responses to climate change in the Arctic. This study was conducted in order to quantify CO2 efflux, using a portable chamber system at representative sites along the Dalton Highway. Study sites included three tundra, two white spruce, and three black spruce forest locations during the winter and spring seasons of 2010–2012; the study of these sites promised better understanding of winter and spring carbon contributions to the annual carbon budget, as well as the respective ablation-ring effects during spring. Three-year spring CO2 efflux depends on soil temperature at 5 cm depth on a regional scale. At their highest, Q10 values were 4.2 × 106, within the exposed tussock tundra of the upland tundra site, which tundra soils warmed from −0.9 to 0.5 °C, involving soil microbial activity. From the forest census (400 m2) of the two white spruce forest sites, CO2 emissions were estimated as 0.09–0.36 gC m−2 day−1 in winter and 0.14–4.95 gC m−2 day−1 in spring, corresponding to 1–3% and 1–27% of annual carbon, respectively. Contributions from spring CO2 emissions are likely to increase as exposed soils widen in average length (major axis) from the east-, west-, south-, and north-side lengths (minor axis). Considering the periods of winter and spring seasons across tundra and boreal forests, average winter- and spring-seasonal CO2 contributions to annual carbon budgets correspond roughly to 14–22% for tundra and 9–24% for boreal forest sites during 2011 and 2012. Spring carbon contributions, such as growing season CO2 emissions, are sensitive to subtle changes at the onset of spring and during the snow-covered period in northern high latitudes, in response to recent Arctic climate change.

scholarly journals Effect of ablation ring and soil temperature on 3-yr spring CO<sub>2</sub> efflux along the trans-Alaska pipeline, Alaska

2014 ◽  
Vol 11 (3) ◽  
pp. 3615-3652 ◽  
Author(s):  
Y. Kim
Keyword(s):  
Climate Change ◽  
Boreal Forest ◽  
Soil Temperature ◽  
Co2 Emissions ◽  
White Spruce ◽  
Co2 Efflux ◽  
Spruce Forest ◽  
Carbon Budgets ◽  
Forest Sites ◽  
Annual Carbon

Abstract. Winter and spring soil CO2 efflux-measurements represent a significant component in the assessment of annual carbon budgets of tundra and boreal forest ecosystems, as a response to climate change in the Arctic. This study was conducted to quantify CO2 efflux using a portable chamber system at representative sites along the trans-Alaska pipeline. The sites here are characterized as three tundra, two white spruce, and three black spruce forest sites during winter and spring seasons of 2010 to 2012; study of these sites will offer a better understanding of winter and spring carbon contributions to the annual carbon budget, as well as their affecting parameters by the effect of ablation ring in spring. 3 yr spring CO2 efflux depends on soil temperature at 5 cm depth on a regional scale. At their highest, Q10 values were 4.2 × 106, within the exposed tussock tundra of the upland tundra site, as tundra soils warmed from −0.9 to 0.5 °C, involving the soil microbial activity. With the forest census (400 m2) of the two white spruce forest sites, CO2 emissions were estimated to be 35 to 145 gC day−1 in winter and 56 to 1980 gC day−1 in spring, corresponding to 1–3 and 1–27% of annual carbon, respectively. The contributions from spring CO2 emissions are likely to increase as exposed soils widen in average length (major axis) from east, west, and south, as well as north-side length (minor axis). Considering the periods of winter and spring seasons across tundra and boreal forests, average winter- and spring-seasonal CO2 contributions to annual carbon budgets correspond roughly to 14–22% in tundra and 9–24% in boreal forest sites during 2011–2012. Contributions from spring carbon comparable to growing season CO2 emissions are sensitive to subtle changes at the onset of spring and during the snow-covered period in northern high latitudes, in response to recent Arctic climate change.

scholarly journals Significance of soil respiration from biological activity in the degradation processes of different types of organic matter

2020 ◽  
Vol 1 (2) ◽  
pp. 171-179
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Temperature Sensitivity ◽  
Soil Co2 Efflux ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Total Soil

Soil respiration is a major component of global carbon cycle. Therefore, it is crucial to understand the environmental controls on soil respiration for evaluating potential response of ecosystems to climate change. In a temperate deciduous forest (located in Northern-Hungary) we added or removed aboveground and belowground litter to determine total soil respiration. We investigated the relationship between total soil CO2 efflux, soil moisture, and soil temperature. Soil CO2 efflux was measured at each plot using soda-lime method. Temperature sensitivity of soil respiration (Q10) was monitored via measuring soil temperature on an hourly basis, while soil moisture was determined monthly. Soil respiration increased in control plots from the second year after implementing the treatment, but results showed fluctuations from one year to another. The effect of doubled litter was less significant than the effect of removal. Removed litter and root inputs caused substantial decrease in soil respiration. We found that temperature was more influential in the control of soil respiration than soil moisture. In plots with no litter Q10 varied in the largest interval. For treatment with doubled litter layer, temperature sensitivity of CO2 efflux did not change considerably. The effect of increasing soil temperature is more conspicuous to soil respiration in litter removal treatments since lack of litter causes greater irradiation. When exclusively leaf litter was considered, the effect of temperature on soil respiration was lower in treatments with added litter than with removed litter. Our results reveal that soil life is impacted by the absence of organic matter, rather than by an excess of organic matter. Results of CO2 emission from soils with different organic matter content can contribute to sustainable land use, considering the changed climatic factors caused by global climate change.

Summary and Synthesis: Past and Future Changes in the Alaskan Boreal Forest

2006 ◽  
Author(s):  
Marilyn W. Walker ◽  
Mary E. Edwards
Keyword(s):  
Boreal Forest ◽  
Bark Beetles ◽  
Fire Regime ◽  
Black Spruce ◽  
Rapid Change ◽  
White Spruce ◽  
Late Glacial ◽  
Fire Frequency ◽  
Tree Resistance ◽  
Forest Sites

Historically the boreal forest has experienced major changes, and it remains a highly dynamic biome today. During cold phases of Quaternary climate cycles, forests were virtually absent from Alaska, and since the postglacial re-establishment of forests ca 13,000 years ago, there have been periods of both relative stability and rapid change (Chapter 5). Today, the Alaskan boreal forest appears to be on the brink of further significant change in composition and function triggered by recent changes that include climatic warming (Chapter 4). In this chapter, we summarize the major conclusions from earlier chapters as a basis for anticipating future trends. Alaska warmed rapidly at the end of the last glacial period, ca 15,000–13,000 years ago. Broadly speaking, climate was warmest and driest in the late glacial and early Holocene; subsequently, moisture increased, and the climate gradually cooled. These changes were associated with shifts in vegetation dominance from deciduous woodland and shrubland to white spruce and then to black spruce. The establishment of stands of fire-prone black spruce over large areas of the boreal forest 5000–6000 years ago is linked to an apparent increase in fire frequency, despite the climatic trend to cooler and moister conditions. This suggests that long-term features of the Holocene fire regime are more strongly driven by vegetation characteristics than directly by climate (Chapter 5). White spruce forests show decreased growth in response to recent warming, because warming-induced drought stress is more limiting to growth than is temperature per se (Chapters 5, 11). If these environmental controls persist, projections suggest that continued climate warming will lead to zero net annual growth and perhaps the movement of white spruce to cooler upland forest sites before the end of the twenty-first century. At the southern limit of the Alaskan boreal forest, spruce bark beetle outbreaks have decimated extensive areas of spruce forest, because warmer temperatures have reduced tree resistance to bark beetles and shortened the life cycle of the beetle from two years to one, shifting the tree-beetle interaction in favor of the insect (Chapter 9).

Tree growth response to climate change at the deciduous–boreal forest ecotone, Ontario, Canada

2005 ◽  
Vol 35 (11) ◽  
pp. 2709-2718 ◽  
Author(s):  
D Goldblum ◽  
L S Rigg
Keyword(s):  
Climate Change ◽  
Boreal Forest ◽  
Sugar Maple ◽  
White Spruce ◽  
Balsam Fir ◽  
Northern Limit ◽  
Monthly Temperature ◽  
Temperature And Precipitation ◽  
The Future ◽  
Forest Ecotone

We consider the implications of climate change on the future of the three dominant forest species, sugar maple (Acer saccharum Marsh.), white spruce (Picea glauca (Moench) Voss), and balsam fir (Abies balsamea (L.) Mill.), at the deciduous–boreal forest ecotone, Ontario, Canada. Our analysis is based on individual species responses to past monthly temperature and precipitation conditions in light of modeled (general circulation model) monthly temperature and precipitation conditions in the study area for the 2080s. We then consider the tree species sensitivity to past climate with predicted conditions for the 2080 period. Sugar maple, located at its northern limit in the study area, shows the greatest potential for increased growth rates under the predicted warming and altered precipitation regime. White spruce is likely to benefit less, while the understory dominant balsam fir is likely to experience a decrease in growth potential. These projected changes would enhance the future status of sugar maple at its northern limit and facilitate range expansion northward in response to global warming.

scholarly journals Short-term effects of biochar on soil CO2 efflux in boreal Scots pine forests

2020 ◽  
Vol 77 (2) ◽  
Author(s):  
Xudan Zhu ◽  
Tingting Zhu ◽  
Jukka Pumpanen ◽  
Marjo Palviainen ◽  
Xuan Zhou ◽  
...  
Keyword(s):  
Carbon Sequestration ◽  
Boreal Forest ◽  
Soil Temperature ◽  
Scots Pine ◽  
Pyrolysis Temperature ◽  
Pine Forest ◽  
Co2 Efflux ◽  
Short Term ◽  
Application Rates ◽  
Scots Pine Forest

Abstract Key message During the first summer, wood biochar amendments increased soil temperature, pH, and soil CO2effluxes in a xeric boreal Scots pine forest. The increase of soil CO2efflux could be largely explained by increases in by soil temperature. Higher biochar application rates (1.0 vs 0.5 kg m−2) led to higher soil CO2efflux while the pyrolysis temperature of biochar (500 or 650 °C) had no effect on soil CO2efflux. Context Using biochar as a soil amendment has been proposed to increase the carbon sequestration in soils. However, a more rapid soil organic matter turnover after biochar application might reduce the effectiveness of biochar applications for carbon sequestration. By raising the pyrolysis temperature, biochar with lower contents of labile carbohydrates can be produced. Aims To better understand the effects of biochar on boreal forest soil, we applied two spruce biochar with different pyrolysis temperatures (500 °C and 650 °C) at amounts of 1.0 and 0.5 kg m−2 in a young xeric Scots pine forest in southern Finland. Methods Soil CO2, microbial biomass, and physiochemical properties were measured to track changes after biochar application during the first summer. Results Soil CO2 increased 14.3% in 1.0 kg m−2 treatments and 4.6% in 0.5 kg m−2. Soil temperature and pH were obviously higher in the 1.0 kg m−2 treatments. Differences in soil CO2 among treatments disappear after correcting by soil temperature and soil moisture. Conclusion Biochar increased soil CO2 mainly by raising soil temperature in the short term. Higher biochar application rates led to higher soil CO2 effluxes. The increase in soil CO2 efflux may be transient. More studies are needed to get the optimum biochar amount for carbon sequestration in boreal forest.

scholarly journals Soil CO<sub>2</sub> efflux from two mountain forests in the eastern Himalayas, Bhutan: components and controls

2017 ◽  
Vol 14 (1) ◽  
pp. 99-110 ◽  
Author(s):  
Norbu Wangdi ◽  
Mathias Mayer ◽  
Mani Prasad Nirola ◽  
Norbu Zangmo ◽  
Karma Orong ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Soil Temperature ◽  
Mixed Forest ◽  
Co2 Efflux ◽  
Measured Temperature ◽  
Mountain Forests ◽  
Broadleaf Forest ◽  
Eastern Himalayas ◽  
Forest Sites ◽  
C Stocks

Abstract. The biogeochemistry of mountain forests in the Hindu Kush Himalaya range is poorly studied, although climate change is expected to disproportionally affect the region. We measured the soil CO2 efflux (Rs) at a high-elevation (3260 m) mixed forest and a lower-elevation (2460 m) broadleaf forest in Bhutan, eastern Himalayas, during 2015. Trenching was applied to estimate the contribution of autotrophic (Ra) and heterotrophic (Rh) soil respiration. The temperature (Q10) and the moisture sensitivities of Rh were determined under controlled laboratory conditions and were used to model Rh in the field. The higher-elevation mixed forest had a higher standing tree stock, reflected in higher soil C stocks and basal soil respiration. Annual Rs was similar between the two forest sites (14.5 ± 1.2 t C ha−1 for broadleaf; 12.8 ± 1.0 t C ha−1 for mixed). Modelled annual contribution of Rh was  ∼  65 % of Rs at both sites with a higher heterotrophic contribution during winter and lower contribution during the monsoon season. Rh, estimated from trenching, was in the range of modelled Rh but showed higher temporal variability. The measured temperature sensitivity of Rh was similar at the mixed and broadleaf forest sites (Q10 2.2–2.3) under intermediate soil moisture but decreased (Q10 1.5 at both sites) in dry soil. Rs closely followed the annual course of field soil temperature at both sites. Covariation between soil temperature and moisture (cold dry winters and warm wet summers) was likely the main cause for this close relationship. Under the prevailing weather conditions, a simple temperature-driven model was able to explain more than 90 % of the temporal variation in Rs. A longer time series and/or experimental climate manipulations are required to understand the effects of eventually occurring climate extremes such as monsoon failures.

scholarly journals Seasonality in a boreal forest ecosystem affects the use of soil temperature and moisture as predictors of soil CO<sub>2</sub> efflux

2011 ◽  
Vol 8 (2) ◽  
pp. 2811-2849 ◽  
Author(s):  
S. M. Niinistö ◽  
S. Kellomäki ◽  
J. Silvola
Keyword(s):  
Boreal Forest ◽  
Soil Temperature ◽  
Temporal Variation ◽  
Temperature Response ◽  
Soil Co2 Efflux ◽  
Pine Forest ◽  
Quadratic Model ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Strong Seasonality

Abstract. Our objectives were to identify factors related to temporal variation of soil CO2 efflux in a boreal pine forest and to evaluate simple predictive models of temporal variation of soil CO2 efflux. Soil CO2 efflux was measured with a portable chamber in a Finnish Scots pine forest for three years, with a fourth year for model evaluation. Plot averages for soil CO2 efflux ranged from 0.04 to 0.90 g CO2 m−2 h−1 during the snow-free period, i.e. May–October, and from 0.04 to 0.13 g CO2 m−2 h−1 in winter. Soil temperature was a good predictor of soil CO2 efflux. A quadratic model of ln-transformed efflux explained 76–82% of the variation over the snow-free period. The results revealed strong seasonality: at a given soil temperature, soil CO2 efflux was higher later in the snow-free period than in spring and early summer. Regression coefficients for temperature (approximations of a Q10 value) of month-specific models decreased with increasing average soil temperatures. Efflux in July, the month of peak photosynthesis, showed no clear response to temperature or moisture. Inclusion of a seasonality index, degree days, improved the accuracy of temperature response models to predict efflux for the fourth year of measurements, which was not used in building of regression models. Underestimation during peak efflux (mid-July to late-August) remained uncorrected. The strong influence of the flux of photosynthates belowground and the importance of root respiration could explain the relative temperature insensitivity observed in July and together with seasonality of growth of root and root-associated mycorrhizal fungi could explain partial failure of models to predict magnitude of efflux in the peak season from mid-July to August. The effect of moisture early in the season was confounded by simultaneous advancement of the growing season and increase in temperature. In a dry year, however, the effect of drought was evident as soil CO2 efflux was some 30% smaller in September than in the previous wet year. Although soil temperature was a good overall predictor of soil CO2 efflux, possibly partly due to its proxy-like quality for covarying processes, strong seasonality of the temperature response observed in this boreal forest corroborates recent findings concerning the importance of seasonal changes in carbon inputs to processes producing CO2 in soil.

scholarly journals Soil temperature responses to climate change along a gradient of upland–riparian transect in boreal forest

2017 ◽  
Vol 143 (1-2) ◽  
pp. 27-41 ◽  
Author(s):  
S . K. Oni ◽  
F. Mieres ◽  
M. N. Futter ◽  
H. Laudon
Keyword(s):  
Climate Change ◽  
Boreal Forest ◽  
Soil Temperature ◽  
Temperature Responses
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