Soil carbon stabilization along climate and stand productivity gradients in black spruce forests of interior Alaska

2005 ◽  
Vol 35 (9) ◽  
pp. 2118-2129 ◽  
Author(s):  
E S Kane ◽  
D W Valentine ◽  
E AG Schuur ◽  
K Dutta
Keyword(s):  
Organic Matter ◽  
Primary Production ◽  
Soil Temperature ◽  
Black Spruce ◽  
Mineral Soil ◽  
Soil C ◽  
Stand Productivity ◽  
Interior Alaska ◽  
C Balance ◽  
Soil C Balance

The amount of soil organic carbon (SOC) in stable, slow-turnover pools is likely to change in response to climate warming because processes mediating soil C balance (net primary production and decomposition) vary with environmental conditions. This is important to consider in boreal forests, which constitute one of the world's largest stocks of SOC. We investigated changes in soil C stabilization along four replicate gradients of black spruce productivity and soil temperature in interior Alaska to develop empirical relationships between SOC and stand and physiographic features. Total SOC harbored in mineral soil horizons decreased by 4.4 g C·m–2 for every degree-day increase in heat sum within the organic soil across all sites. Furthermore, the proportion of relatively labile light-fraction (density <1.6 g·cm–3) soil organic matter decreased significantly with increased stand productivity and soil temperature. Mean residence times of SOC (as determined by Δ14C) in dense-fraction (>1.6 g·cm–3) mineral soil ranged from 282 to 672 years. The oldest SOC occurred in the coolest sites, which also harbored the most C and had the lowest rates of stand production. These results suggest that temperature sensitivities of organic matter within discrete soil pools, and not just total soil C stocks, need to be examined to project the effects of changing climate and primary production on soil C balance.

Productivity and nutrient cycling in taiga forest ecosystems

1983 ◽  
Vol 13 (5) ◽  
pp. 747-766 ◽  
Author(s):  
Keith Van Cleve ◽  
Lola Oliver ◽  
Robert Schlentner ◽  
Leslie A. Viereck ◽  
C. T. Dyrness
Keyword(s):  
Nutrient Cycling ◽  
Soil Temperature ◽  
Forest Floor ◽  
Black Spruce ◽  
Lignin Content ◽  
Mineral Soil ◽  
Forest Types ◽  
Interior Alaska ◽  
Taiga Forest ◽  
Tree Production

This paper considers the productivity and nutrient cycling in examples of the major forest types in interior Alaska. These ecosystem properties are examined from the standpoint of the control exerted over them by soil temperature and forest-floor chemistry. We conclude that black spruce Piceamariana (Mill.) B.S.P. occupies the coldest, wettest sites which support tree growth in interior Alaska. Average seasonal heat sums (1132 ± 32 degree days (DD)) for all other forest types were significantly higher than those encountered for black spruce (640 ± 40 DD). In addition, black spruce ecosystems display the highest average seasonal forest-floor and mineral-soil moisture contents. Forest-floor chemistry interacts with soil temperature in black spruce to produce the most decay-resistant organic matter. In black spruce the material is characterized by the highest lignin content and widest C/N (44) and C/P (404) ratios. Across the range of forest types examined in this study, soil temperature is strongly related to net annual aboveground tree production and the annual tree requirement for N, P, K, Ca, and Mg. Forest floor C/N and C/P ratios are strongly related to annual tree N and P requirement and the C/N ratio to annual tree production. In all cases these controls act to produce, in black spruce, the smallest accumulation of tree biomass, standing crop of elements, annual production, and element requirement in aboveground tree components.

Variation in postfire organic layer thickness in a black spruce forest complex in interior Alaska and its effects on soil temperature and moisture

2005 ◽  
Vol 35 (9) ◽  
pp. 2164-2177 ◽  
Author(s):  
Eric S Kasischke ◽  
Jill F Johnstone
Keyword(s):  
Soil Temperature ◽  
Fuel Consumption ◽  
Fire History ◽  
Black Spruce ◽  
Mineral Soil ◽  
Stand Age ◽  
Organic Layer ◽  
Layer Depth ◽  
Interior Alaska ◽  
Soil Temperature And Moisture

This study investigated the relationship between climate and landscape characteristics and surface fuel consumption as well as the effects of variations in postfire organic layer depth on soil temperature and moisture in a black spruce (Picea mariana (Mill.) BSP) forest complex in interior Alaska. Mineral soil moisture and temperature at the end of the growing season and organic layer depth were measured in three burns occurring in different years (1987, 1994, 1999) and in adjacent unburned stands. In unburned stands, average organic layer and humic layer depth increased with stand age. Mineral soil temperature and moisture varied as a function of the surface organic layer depth in unburned stands, indicating that as a stand matures, the moisture content of the deep duff layer is likely to increase as well. Fires reduced the depth of the surface organic layers by 5 to 24 cm. Within each burn we found that significant variations in levels of surface fuel consumption were related to several factors, including mineral soil texture, presence or absence of permafrost, and timing of the fires with respect to seasonal permafrost thaw. While seasonal weather patterns contribute to variations in fuel moisture and consumption during fires, interactions among the soil thermal regime, surface organic layer depth, and previous fire history are also important in controlling patterns of surface fuel consumption.

scholarly journals Ryegrass root and shoot residues differentially affect short-term priming of soil organic matter and net soil C-balance

2019 ◽  
Vol 93 ◽  
pp. 103096 ◽  
Author(s):  
Lumbani Mwafulirwa ◽  
Elizabeth M. Baggs ◽  
Nick Morley ◽  
Eric Paterson
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Short Term ◽  
Soil C ◽  
C Balance ◽  
Soil C Balance

Response of black spruce (Piceamariana) ecosystems to soil temperature modification in interior Alaska

1990 ◽  
Vol 20 (9) ◽  
pp. 1530-1535 ◽  
Author(s):  
Keith Van Cleve ◽  
Walter C. Oechel ◽  
John L. Hom
Keyword(s):  
Soil Temperature ◽  
Soil Solution ◽  
Forest Floor ◽  
Black Spruce ◽  
Mineral Soil ◽  
Nutrient Content ◽  
Experimental Period ◽  
Degree Days ◽  
Soil Heating ◽  
Interior Alaska

This paper reports results of a study designed to examine the control that soil temperature exerts on soil processes associated with nutrient flux, and in turn, on tree nutrition in interior Alaska black spruce ecosystems. Approximately 50 m2 of forest floor in a 140-year-old black spruce ecosystem, which had developed on permafrost, was heated to 8–10 °C above ambient temperature. This perturbation amounted to approximately a 1589 degree-day seasonal heat sum (above 0 °C), 1026 degree-days above the control total of 563 degree-days. The forest floor, surface 5 cm of mineral soil, and soil solution were compared with those of an adjacent control plot to evaluate the change in nutrient content and decomposition rate of the forest floor. The nutritional response to soil heating of current black spruce foliage also was evaluated. Soil heating significantly increased decomposition of the forest floor, principally because of an increase in biomass loss of the O21 layer. The increased decomposition resulted in greater extractable N and P concentrations in the forest floor, higher N concentrations in the soil solution, and elevated spruce needle N, P, and K concentrations for the experimental period. These results are discussed in light of the importance of soil temperature and other state factors that mediate ecosystem function.

Evidence of temperature control of production and nutrient cycling in two interior Alaska black spruce ecosystems

1981 ◽  
Vol 11 (2) ◽  
pp. 259-274 ◽  
Author(s):  
Keith Van Cleve ◽  
Richard Barney ◽  
Robert Schlentner
Keyword(s):  
Black Spruce ◽  
Mineral Soil ◽  
Soil Nutrient ◽  
North Slope ◽  
Nutrient Pools ◽  
Soil Biological Activity ◽  
Nutrient Mineralization ◽  
Interior Alaska ◽  
Soil Temperatures ◽  
And Function

Selected indices of structure and function were used to evaluate the effect of differing soil thermal regimes on soil-permafrost-dominated (muskeg) and permafrost-free (north-slope) black spruce ecosystems in interior Alaska. The poorly drained, permafrost site displayed cooler soil temperatures and higher soil moisture content than were encountered on the well-drained north slope. Mineral soil nutrient pools generally were largest on the permafrost site. However, low soil temperature acted as a negative feedback control, suppressing soil biological activity, nutrient mineralization, and tree primary production to lower levels on the soil-permafrost-dominated site as compared with the permafrost-free site. Forty percent larger accumulation of tree biomass and 80% greater annual tree productivity occurred on the warmer site.

scholarly journals Influence of climate change factors on carbon dynamics in northern forested peatlands

2006 ◽  
Vol 86 (Special Issue) ◽  
pp. 269-280 ◽  
Author(s):  
C. C. Trettin ◽  
R. Laiho ◽  
K. Minkkinen ◽  
J. Laine
Keyword(s):  
Climate Change ◽  
Organic Matter ◽  
Management Practices ◽  
Atmospheric Temperature ◽  
Soil C ◽  
Altered Hydrology ◽  
Biogeochemical Models ◽  
C Dynamics ◽  
C Balance ◽  
C Cycle

Peatlands are carbon-accumulating wetland ecosystems, developed through an imbalance among organic matter production and decomposition processes. Soil saturation is the principal cause of anoxic conditions that constrain organic matter decay. Accordingly, changes in the hydrologic regime will affect the carbon (C) dynamics in forested peatlands. Our objective is to review ecological studies and experiments on managed peatlands that provide a basis for assessing the effects of an altered hydrology on C dynamics. We conclude that climate change influences will be mediated primarily through the hydrologic cycle. A lower water table resulting from altered precipitation patterns and increased atmospheric temperature may be expected to decrease soil CH4 and increase CO2 emissions from the peat surface. Correspondingly, the C balance in forested peatlands is also sensitive to management and restoration prescriptions. Increases in soil CO2 efflux do not necessarily equate with net losses from the soil C pool. While the fundamentals of the C balance in peatlands are well-established, the combined affects of global change stressors and management practices are best considered using process-based biogeochemical models. Long-term studies are needed both for validation and to provide a framework for longitudinal assessments of the peatland C cycle. Key words: Peatland, carbon cycle, methane, forest, wetland.

scholarly journals Soil organic carbon dynamics along a climatic gradient in a southern Appalachian spruce–fir forest

2007 ◽  
Vol 37 (7) ◽  
pp. 1161-1172 ◽  
Author(s):  
C.E. Tewksbury ◽  
H. Van Miegroet
Keyword(s):  
Soil Temperature ◽  
Residence Time ◽  
Mean Residence Time ◽  
Forest Floor ◽  
Elevation Gradient ◽  
Mineral Soil ◽  
Carbon Dynamics ◽  
Effect Of Temperature ◽  
Degree Days ◽  
Soil C

A field study was conducted in a high-elevation spruce–fir ( Picea rubens Sarg. – Abies fraseri (Pursh.) Poir) forest in the Great Smoky Mountains National Park to assess the effect of temperature on soil C storage and dynamics. In eight plots along an elevation gradient (1500–1900 m), we measured soil temperature, forest floor and mineral soil C, litter decomposition, soil respiration, and forest floor mean residence time. Mean annual soil temperature and annual degree-days above 5 °C were inversely correlated with elevation. Total soil C (166–241 Mg·ha–1) showed no trend with elevation, while forest floor C accumulation (16.3–35.9 Mg·ha–1) decreased significantly with elevation. Carbon dynamics did not follow a consistent elevation pattern; however, the cooler upper elevations showed the lowest C turnover as indicated by the lowest needle decomposition rate (k = 0.0231·year–1) and the longest mean residence time of forest floor C (22 years). Mean annual CO2efflux from the soil (1020–1830 kg C·ha–1·year–1) was negatively correlated with mean annual soil temperatures and annual degree-days above 5 °C. This gradient study offers useful insights into C release patterns under future warming scenarios, and suggests that the highest elevation may be most susceptible to global warming.

Effets du scarifiage sur les propriétés du sol et l'ensemencement naturel dans une pessière noire à mousses de la forêt boréale québécoise

1996 ◽  
Vol 26 (1) ◽  
pp. 72-86 ◽  
Author(s):  
Marcel Prévost
Keyword(s):  
Organic Matter ◽  
Black Spruce ◽  
Block Design ◽  
Mineral Soil ◽  
Organic Matter Content ◽  
Control Treatment ◽  
Winter Period ◽  
Soil Warming ◽  
Total N ◽  
Humus Layer

Two types of scarification (cone and disk) were applied at two intensities (simple and double passes), in a randomized complete block design, established alongside buffer stands of spruce protective of water courses, that provided a natural seed source. Treatment effects on seedbed evolution, natural seeding of black spruce (Piceamariana (Mill.) BSP), competing vegetation, and soil physical and chemical properties were examined over a 3-year period. In situ nitrogen mineralization was also studied, using the buried-bag method. All scarification treatments created a surface horizon (0–10 cm) with 80% less organic matter content than the control treatment. However, treatments tended to loosen the exposed deep layers, creating microsites whose compactness appeared adequate for root development (1.07–1.22 Mg/m3). The organic matter loss mainly decreased exchangeable K and Mg in the surface 20 cm of scarified microsites. Scarification had little impact on total N of sampled profiles and clearcutting did not increase N mineralization with regard to the forest, during the first year after disturbance. The weak soil warming and the stability of temperatures under the unscarified humus suggest that clearcutting did not significantly enhanced microbial activity on the site. However, removal of the insulating humus layer allowed a significant summer soil warming in the furrows. Despite this, scarified microsites were characterized by N immobilization during the first growing season after treatment. However, net N production was positive during the winter period, presumably because of a N-flux phenomenon. Scarification improved black spruce regeneration by natural seeding. Three years after treatment, stocking levels reached 40 to 51% in the scarified sectors while they reached 31% in the controls, this gap being mainly attributed to the second germination year. The difference can be explained by the improved receptivity of bare mineral soil, well-decomposed humus, and mixed mineral–organic seedbeds that covered 12–20% of the scarified areas immediately after treatment. Generally, results indicate that microsites created by a light scarification are as receptive as microsites created by a severe perturbation. Finally, every scarification treatment efficiently controlled the ericaceous shrub cover during the first 3 years after treatment.

scholarly journals Environmental factors regulating winter CO<sub>2</sub> flux in snow-covered boreal forest soil, interior Alaska

2012 ◽  
Vol 9 (1) ◽  
pp. 1129-1159 ◽  
Author(s):  
Y. Kim ◽  
Y. Kodama
Keyword(s):  
Environmental Factors ◽  
Soil Temperature ◽  
Forest Soil ◽  
Atmospheric Pressure ◽  
Co2 Emission ◽  
Black Spruce ◽  
Co2 Flux ◽  
Atmospheric Temperature ◽  
Spruce Forest ◽  
Interior Alaska

Abstract. Winter CO2 flux is an important element to assess when estimating the annual carbon budget on regional and global scales. However, winter observation frequency is limited due to the extreme cold weather in sub-Arctic and Arctic ecosystems. In this study, the continuous monitoring of winter CO2 flux in black spruce forest soil of interior Alaska was performed using NDIR CO2 sensors at 10, 20, and 30 cm above the soil surface during the snow-covered period (DOY 357 to 466) of 2006/2007. The atmospheric pressure was divided into four phases: >1000 hPa (HP: high pressure); 985<P<1000 (IP: intermediate pressure); <986 hPa (LP: low pressure); and a snow-melting period (MP); for the quantification of the effect of the environmental factors determining winter CO2 flux. The winter CO2 fluxes were 0.22 ± 0.02, 0.23 ± 0.02, 0.25 ± 0.03, and 0.17 ± 0.02 gCO2-C/m2 d−1 for the HP, IP, LP, and MP phases, respectively. Wintertime CO2 emission represents 20 % of the annual CO2 emissions in this boreal black spruce forest soil. Atmospheric temperature, pressure, and soil temperature correlate at levels of 56, 25, and 31 % to winter CO2 flux, respectively, during the snow-covered period of 2006/2007, when snow depth experienced one of its lowest totals of the past 80 years. Atmospheric temperature and soil temperature at 5 cm depth, modulated by atmospheric pressure, were found to be significant factors in determining winter CO2 emission and fluctuation in snowpack. Regional/global process-based carbon cycle models should be reassessed to account for the effect of winter CO2 emissions, regulated by temperature and soil latent-heat flux, in the snow-covered soils of Arctic and sub-Arctic terrestrial ecosystems of the Northern Hemisphere.

scholarly journals Effects of free atmospheric CO<sub>2</sub> enrichment (FACE), N fertilization and poplar genotype on the physical protection of carbon in the mineral soil of a polar plantation after five years

2006 ◽  
Vol 3 (4) ◽  
pp. 479-487 ◽  
Author(s):  
M. R. Hoosbeek ◽  
J. M. Vos ◽  
E. J. Bakker ◽  
G. E. Scarascia-Mugnozza
Keyword(s):  
Organic Matter ◽  
Net Primary Production ◽  
Mineral Soil ◽  
Co2 Enrichment ◽  
N Fertilization ◽  
Soil C ◽  
C Storage ◽  
Short Rotation ◽  
The Stability ◽  
Choice Of Species

Abstract. Free air CO2 enrichment (FACE) experiments in aggrading forests and plantations have demonstrated significant increases in net primary production (NPP) and C storage in forest vegetation. The extra C uptake may also be stored in forest floor litter and in forest soil. After five years of FACE treatment at the EuroFACE short rotation poplar plantation, the increase of total soil C% was larger under elevated than under ambient CO2. However, the fate of this additional C allocated belowground remains unclear. The stability of soil organic matter is controlled by the chemical structure of the organic matter and the formation of micro-aggregates (within macro-aggregates) in which organic matter is stabilized and protected. FACE and N-fertilization treatment did not affect the micro- and macro-aggregate weight, C or N fractions obtained by wet sieving. However, Populus euramericana increased the small macro-aggregate and free micro-aggregate weight and C fractions. The obtained macro-aggregates were broken up in order to isolate recently formed micro-aggregates within macro-aggregates (iM-micro-aggregates). FACE increased the iM-micro-aggregate weight and C fractions, although not significantly. This study reveals that FACE did not affect the formation of aggregates. We did, however, observe a trend of increased stabilization and protection of soil C in micro-aggregates formed within macro-aggregates under FACE. Moreover, the largest effect on aggregate formation was due to differences in species, i.e. poplar genotype. P. euramericana increased the formation of free micro-aggregates which means that more newly incorporated soil C was stabilized and protected. The choice of species in a plantation, or the effect of global change on species diversity, may therefore affect the stabilization and protection of C in soils.

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