scholarly journals Early summer soil moisture contribution to Western European summer warming

2021 ◽  
Author(s):  
A. I. Stegehuis ◽  
M. M. Vogel ◽  
R Vautard ◽  
P Ciais ◽  
A. J. Teuling ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Early Summer ◽  
Summer Warming ◽  
Western European

scholarly journals Climate Differently Impacts the Growth of Coexisting Trees and Shrubs under Semi-Arid Mediterranean Conditions

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 381
Author(s):  
J. Julio Camarero ◽  
Cristina Valeriano ◽  
Antonio Gazol ◽  
Michele Colangelo ◽  
Raúl Sánchez-Salguero
Keyword(s):  
Soil Moisture ◽  
Radial Growth ◽  
Pinus Halepensis ◽  
Growth Dynamics ◽  
Early Summer ◽  
Growth Responses ◽  
Shrub Species ◽  
High Soil Moisture ◽  
Semi Arid ◽  
Mediterranean Conditions

Background and Objectives—Coexisting tree and shrub species will have to withstand more arid conditions as temperatures keep rising in the Mediterranean Basin. However, we still lack reliable assessments on how climate and drought affect the radial growth of tree and shrub species at intra- and interannual time scales under semi-arid Mediterranean conditions. Materials and Methods—We investigated the growth responses to climate of four co-occurring gymnosperms inhabiting semi-arid Mediterranean sites in northeastern Spain: two tree species (Aleppo pine, Pinus halepensis Mill.; Spanish juniper, Juniperus thurifera L.) and two shrubs (Phoenicean juniper, Juniperus phoenicea L.; Ephedra nebrodensis Tineo ex Guss.). First, we quantified the intra-annual radial-growth rates of the four species by periodically sampling wood samples during one growing season. Second, we quantified the climate–growth relationships at an interannual scale at two sites with different soil water availability by using dendrochronology. Third, we simulated growth responses to temperature and soil moisture using the forward, process-based Vaganov‒Shashkin (VS-Lite) growth model to disentangle the main climatic drivers of growth. Results—The growth of all species peaked in spring to early summer (May–June). The pine and junipers grew after the dry summer, i.e., they showed a bimodal growth pattern. Prior wet winter conditions leading to high soil moisture before cambium reactivation in spring enhanced the growth of P. halepensis at dry sites, whereas the growth of both junipers and Ephedra depended more on high spring–summer soil moisture. The VS-Lite model identified these different influences of soil moisture on growth in tree and shrub species. Conclusions—Our approach (i) revealed contrasting growth dynamics of co-existing tree and shrub species under semi-arid Mediterranean conditions and (ii) provided novel insights on different responses as a function of growth habits in similar drought-prone regions.

scholarly journals The temporally varying roles of rainfall, snowmelt and soil moisture for debris flow initiation in a snow-dominated system

2018 ◽  
Vol 22 (6) ◽  
pp. 3493-3513 ◽  
Author(s):  
Karin Mostbauer ◽  
Roland Kaitna ◽  
David Prenner ◽  
Markus Hrachowitz
Keyword(s):  
Soil Moisture ◽  
Debris Flow ◽  
High Intensity ◽  
Debris Flows ◽  
Regional Scale ◽  
Early Summer ◽  
Temporal Separation ◽  
Antecedent Soil Moisture ◽  
Trigger Mechanisms ◽  
Debris Flow Initiation

Abstract. Debris flows represent frequent hazards in mountain regions. Though significant effort has been made to predict such events, the trigger conditions as well as the hydrologic disposition of a watershed at the time of debris flow occurrence are not well understood. Traditional intensity-duration threshold techniques to establish trigger conditions generally do not account for distinct influences of rainfall, snowmelt, and antecedent moisture. To improve our knowledge on the connection between debris flow initiation and the hydrologic system at a regional scale, this study explores the use of a semi-distributed conceptual rainfall–runoff model, linking different system variables such as soil moisture, snowmelt, or runoff with documented debris flow events in the inner Pitztal watershed, Austria. The model was run on a daily basis between 1953 and 2012. Analysing a range of modelled system state and flux variables at days on which debris flows occurred, three distinct dominant trigger mechanisms could be clearly identified. While the results suggest that for 68 % (17 out of 25) of the observed debris flow events during the study period high-intensity rainfall was the dominant trigger, snowmelt was identified as the dominant trigger for 24 % (6 out of 25) of the observed debris flow events. In addition, 8 % (2 out of 25) of the debris flow events could be attributed to the combined effects of low-intensity, long-lasting rainfall and transient storage of this water, causing elevated antecedent soil moisture conditions. The results also suggest a relatively clear temporal separation between the distinct trigger mechanisms, with high-intensity rainfall as a trigger being limited to mid- and late summer. The dominant trigger in late spring/early summer is snowmelt. Based on the discrimination between different modelled system states and fluxes and, more specifically, their temporally varying importance relative to each other, this exploratory study demonstrates that already the use of a relatively simple hydrological model can prove useful to gain some more insight into the importance of distinct debris flow trigger mechanisms. This highlights in particular the relevance of snowmelt contributions and the switch between mechanisms during early to mid-summer in snow-dominated systems.

scholarly journals Compost and soil moisture effects on seasonal carbon and nitrogen dynamics, greenhouse gas fluxes and global warming potential of semi-arid soils

2019 ◽  
Vol 8 (S1) ◽  
pp. 367-376 ◽  
Author(s):  
Mavis Badu Brempong ◽  
Urszula Norton ◽  
Jay B. Norton
Keyword(s):  
Global Warming ◽  
Soil Moisture ◽  
Global Warming Potential ◽  
Carbon Dioxide Emissions ◽  
Inorganic Nitrogen ◽  
Early Summer ◽  
Late Spring ◽  
Late Winter ◽  
Normal Soil ◽  
Soil Inorganic

Abstract Purpose An 8-week incubation study was conducted to monitor soil inorganic nitrogen (N), dissolved organic carbon (DOC), greenhouse gases (GHG) [CO2, N2O and CH4] and cumulative global warming potential (GWP) in dryland soil. Methods Soil was amended with variable rates of compost (zero, 15, 30 and 45 dry Mg ha−1) and soil moistures [5% (dry), 7% (normal) and 14% (wet) water filled pore space (WFPS)] and experienced biweekly temperature transitions from 5 °C (late winter) to 10 °C (early spring) to 15 °C (late spring) to 25 °C (early summer). Results The addition of 30 and 45 Mg ha−1 compost enhanced N mineralization with 13% more soil inorganic N (7.49 and 7.72 µg Ng−1 day−1, respectively) during early summer compared with lower compost rates. Normal and wet soils had 35% more DOC in the late spring (an average of 34 µg g−1 day−1) compared to the dry WFPS, but transitioning from late spring to early summer, DOC at all soil WFPS levels increased. Highest rates of compost were not significant sources of GHG with normal soil WFPS, compared with lower compost rates. Carbon dioxide emissions increased by 59 and 15%, respectively, as soil WFPS increased from dry to normal and normal to wet. Soils with normal WFPS were the most effective CH4 sink. Conclusion One-time application of high compost rates to dryland soils leads to enhanced N and C mineralization under normal soil moisture and warmer temperature of the summer but will not pose significant global warming dangers to the environment through GHG emissions since soils are rarely wet.

Seasonal and diurnal trends of heat pulse velocity in Douglas-fir and ponderosa pine

1986 ◽  
Vol 16 (4) ◽  
pp. 814-821 ◽  
Author(s):  
W. Lopushinsky
Keyword(s):  
Soil Moisture ◽  
Ponderosa Pine ◽  
Heat Pulse ◽  
Pulse Velocity ◽  
Early Summer ◽  
Douglas Fir ◽  
Evaporative Demand ◽  
Maximum Heat ◽  
Weather Patterns ◽  
Summer Maximum

Seasonal trends of heat pulse velocity in the trunks of 55-year-old ponderosa pine (Pinusponderosa Dougl. ex Laws.) and Douglas-fir (Pseudotsugamenziesii var. glauca (Beissn.) Franco) trees showed large yearly variations related to weather patterns. Onset of sap movement in the spring, seasonal variations, and summer declines in response to decreasing moisture were similar for Douglas-fir and ponderosa pine. When soil moisture was not limiting, rates of heat pulse velocity in both species were significantly related to air temperature, solar radiation, and vapor pressure deficit. As soil moisture decreased during the summer, rates of heat pulse velocity no longer followed evaporative demand. In both species, sap movement also occurred at night. Diurnal trends of heat pulse velocity also were similar in both species. During early summer, maximum heat pulse velocity occurred at midday; in the fall, maximum rates occurred earlier. The similarity of seasonal and diurnal trends of heat pulse velocity and responses to variation in site conditions suggest that on the site studied, transpiration behavior in ponderosa pine and Douglas-fir trees generally is similar.

An analysis of the outbreaks of the Australian Plague Locust, Chortoicetes terminifera (Walker) during the seasons 1940-41 to 1944-45.

1953 ◽  
Vol 1 (1) ◽  
pp. 70 ◽  
Author(s):  
LR Clark
Keyword(s):  
Soil Moisture ◽  
High Temperatures ◽  
Regional Differences ◽  
Early Summer ◽  
Late Spring ◽  
Seasonal Occurrence ◽  
Severe Winter ◽  
Biotic Factor ◽  
Main Area ◽  
Australian Plague Locust

Outbreaks of the Australian plague locust, Chortoicetes terminifera (Walker), occurred each locus: season from 1940-41 to 1944-45. The largest outbreak, that of 1942-43, was less severe than those recorded in 1937-38, 1938-39, and 1939-40. Consideration of the course of these recent outbreaks in relation to temperature and moisture has again demonstrated the importance of these factors as determinants of the regional and seasonal occurrence of swarms. The curve of limiting conditions for the persistence of swarm populations, obtained by Key (1942), was a useful guide for the interpretation of events in the present analysis. However, a number of discrepancies occurred. These were due probably to a variety of causes, e.g, the kind of infestation concerned, the crudenessof the monthly Meyer ratio as an index of soil moisture and pasture conditions, and regional differences in the upper moisture limits at high temperatures. The results of the present investigation suggest that:(a) The limiting Meyer ratios for the persistence or development of a spring infestation of small, weakly gregarious swarms at temperatures between 60 and 70�F. exceed 4-5; either when the September Meyer ratio is 5 or less, or when the spring is preceded by a severe winter drought.( b ) At temperatures around 75'F., the maximum Meyer ratio at which swarms can exist is approximately 20. (c) At temperatures near the estimated hatching threshold of 57.5'F., swarm hatchings can occur at Meyer ratios as low as 4-5. The collapse of the 1942-43 outbreak in part of the main area infested was due apparently to parasitism by an unidentified fly. Similarly, a biotic factor, possibly the same parasite, was largely responsible for the decline of the 1943-44 outbreak during the late spring and early summer.

scholarly journals Topography-based modelling reveals high spatial variability and seasonal emission patches in forest floor methane flux

2020 ◽  
Author(s):  
Elisa Vainio ◽  
Olli Peltola ◽  
Ville Kasurinen ◽  
Antti-Jussi Kieloaho ◽  
Eeva-Stiina Tuittila ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Spatial Variability ◽  
Boreal Forest ◽  
Forest Floor ◽  
Methane Flux ◽  
Early Summer ◽  
Ground Vegetation ◽  
Small Scale ◽  
Ch4 Flux ◽  
Ch4 Uptake

Abstract. Boreal forest soils are globally an important sink for methane (CH4), while these soils are also capable to emit CH4 under favourable conditions. Soil wetness is a well-known driver of CH4 flux, and the wetness can be estimated with several terrain indices developed for the purpose. The aim of this study was to quantify the spatial variability of the forest floor CH4 flux with a topography-based upscaling method connecting the flux with its driving factors. We conducted spatially extensive forest floor CH4 flux and soil moisture measurements, complemented with ground vegetation classification, in a boreal pine forest. We then modelled the soil moisture with a Random Forest model using topography, based on which we upscaled the forest floor CH4 flux – this was performed for two seasons: May–July and August–October. Our results demonstrate high spatial heterogeneity in the forest floor CH4 flux, resulting from the soil moisture variability, as well as on the related ground vegetation. The spatial variability in the soil moisture and consequently in the CH4 flux was higher in the early summer compared to the autumn period, and overall the CH4 uptake rate was higher in autumn compared to early summer. In the early summer there were patches emitting high amounts of CH4, however, these wet patches got drier and smaller in size towards the autumn, which was enough for changing their dynamics to CH4 uptake. The results highlight the small-scale spatial variability of the boreal forest floor CH4 flux, and the importance of soil chamber placement in order to obtain spatially representative CH4 flux results. We recommend that a site of similar size and topographical variation would require 15–20 sample points in order to achieve accurate forest floor CH4 flux.

scholarly journals Life cycle of ground beetle Chlaenius tristis reticulatus Motschulsky, 1844 (Coleoptera: Carabidae) in the condition of Western Transbaikalia

2020 ◽  
Vol 418 ◽  
pp. 19-24
Author(s):  
L.Ts. Khobrakova ◽  
◽  
S.G. Rudykh ◽  
Ts. Ulzii ◽  
Ch. Gantigmaa ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Life Cycle ◽  
Ground Beetle ◽  
Early Summer ◽  
Related Structure ◽  
Young Generation ◽  
Seasonal Activity ◽  
Western Transbaikalia ◽  
Age Related ◽  
One Year

In the conditions of Western Transbaikalia, Chlaenius tristis reticulatus Motschulsky, 1844 has a one-year late spring – early summer life cycle with the hibernation of a young generation of beetles. The interpretation of their life cycle is based on the study of sex and age-related structure of imago, the seasonal activity of generative females, the above-ground activity of larvae, and stages of the development of beetles in the laboratory conditions. The changes in the seasonal activity of beetles on meadows with different soil moisture (steppificated, moistened, and marshy meadows) were identified.

scholarly journals Soil CO<sub>2</sub> efflux of a larch forest in northern Japan

2010 ◽  
Vol 7 (11) ◽  
pp. 3447-3457 ◽  
Author(s):  
N. Liang ◽  
T. Hirano ◽  
Z.-M. Zheng ◽  
J. Tang ◽  
Y. Fujinuma
Keyword(s):  
Soil Moisture ◽  
Soil Temperature ◽  
Ecosystem Respiration ◽  
Late Summer ◽  
Early Summer ◽  
Larch Forest ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Soil C ◽  
Northern Japan

Abstract. We had continuously measured soil CO2 efflux (Rs) in a larch forest in northern Japan at hourly intervals for the snow-free period in 2003 with an automated chamber system and partitioned Rs into heterotrophic respiration (Rh) and autotrophic respiration (Rr) by using the trench method. In addition, we applied the soil CO2 concentration gradients method to continuously measure soil CO2 profiles under snowpack in the snowy period and to partition Rs into topsoil (Oa and A horizons) CO2 efflux (Ft) with a depth of 0.13 m and sub-soil (C horizon) CO2 efflux (Fc). We found that soil CO2 effluxes were strongly affected by the seasonal variation of soil temperature but weakly correlated with soil moisture, probably because the volumetric soil moisture (30–40% at 95% confidence interval) was within a plateau region for root and microbial activities. The soil CO2 effluxes changed seasonally in parallel with soil temperature in topsoil with the peak in late summer. On the other hand, the contribution of Rr to Rs was the largest at about 50% in early summer, when canopy photosynthesis and plant growth were more active. The temperature sensitivity (Q10) of Rr peaked in June. Under snowpack, Rs was stable until mid-March and then gradually increased with snow melting. Rs summed up to 79 gC m−2 during the snowy season for 4 months. The annual Rs was determined at 934 gC m−2 y−1 in 2003, which accounted for 63% of ecosystem respiration. The annual contributions of Rh and Rs to Rs were 57% and 43%, respectively. Based on the gradient approach, Rs was partitioned vertically into litter (Oi and Oe horizons) with a depth of 0.01–0.02 m, topsoil and sub-soil respirations with proportions of 6, 72 and 22%, respectively, on an annual basis. The vertical distribution of CO2 efflux was consistent with those of soil carbon and root biomass.

Time-lagged effects of spring Tibetan Plateau soil moisture on the monsoon over China in early summer

2007 ◽  
Vol 28 (1) ◽  
pp. 55-67 ◽  
Author(s):  
K. C. Chow ◽  
Johnny C. L. Chan ◽  
Xueli Shi ◽  
Yiming Liu ◽  
Yihui Ding
Keyword(s):  
Soil Moisture ◽  
Tibetan Plateau ◽  
Early Summer ◽  
Lagged Effects ◽  
Time Lagged

scholarly journals Oversummer Survival of Monilinia vaccinii-corymbosi in Relation to Pseudosclerotial Maturity and Soil Surface Environment

Plant Disease ◽  
2001 ◽  
Vol 85 (7) ◽  
pp. 723-730 ◽  
Author(s):  
K. D. Cox ◽  
H. Scherm
Keyword(s):  
Soil Moisture ◽  
Ground Cover ◽  
Soil Surface ◽  
Field Capacity ◽  
Bare Soil ◽  
Sole Source ◽  
Early Summer ◽  
Soil Temperatures ◽  
Maturity Degree ◽  
Surface Environment

Pseudosclerotia (infected, mummified fruit) on the orchard floor act as oversummering and overwintering structures and the sole source of primary inoculum of Monilinia vaccinii-corymbosi, the causal agent of mummy berry disease of blueberry. Survival of pseudosclerotia may be affected by their maturity (degree of stromatization), which can vary considerably at the time of fruit abscission in early summer, and by variations in the soil surface environment. From July through October in 2 years, survival of pseudosclerotia of varying initial maturity (expressed as the proportion of fruit containing mature, melanized entostromata; immature, nonmelanized entostromata; or undifferentiated mycelia) was investigated in the laboratory relative to soil surface temperature and soil moisture content and in the field in relation to shading (full sun versus 50% shade) and ground cover (bare soil versus grass). In the laboratory, oversummer survival, expressed as the percentage of intact pseudosclerotia at the end of the experiment, was higher for cool soil temperatures (approximately 15°C), soils drier than field capacity, and pseudosclerotia containing mature entostromata. In the field, survival was related solely to initial maturity of pseudosclerotia and was highest for pseudosclerotia containing mature entostromata. Shading or grass ground cover did not significantly (P > 0.05) affect oversummer survival, presumably because they did not greatly modify soil temperature or soil moisture. When individual, intact pseudosclerotia were tested for viability using fluorescein diacetate staining, a linear relationship (r = 0.982, P < 0.0001, n = 90) between viable and intact pseudosclerotia was observed, supporting the use of the percentage of intact pseudosclerotia as a measure of oversummer survival.

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