New look at understanding hydrological role of forest

The article is concerned with the discussion of the reasons for the contradictions existing in the assessment of the hydrological role of forests. The authors believe that the accumulation of new information related to seemingly well-studied processes and phenomena necessitates revisions of traditional views and leads to new knowledge of the hydrological role of forests. Various conceptual approaches to assessing the hydrological role of forests in different geographic conditions are considered. System analysis of the materials obtained by the authors and literature data made it possible to identify the features of the hydrological cycle depending on the structure of forests and climatic conditions. The data of 460 snow surveys in the period of maximum snow reserves in 212 forest stands growing in different climatic and ecological conditions were used. The comparison of the features of snow moisture balance of the forest and treeless ecosystems in different climatic conditions contributed to understanding the reasons for the contradictory assessments of the hydrological role of forests. The authors showed that in the conditions of mild and warm winters, forests are more powerful evaporators of snow moisture than treeless sites and in conditions of severe winters with frequent snowstorms, they are the accumulators of snow moisture and sources of river flow. The paper presents a conceptual model describing the mechanisms of water cycle in the forests of the boreal zone, which determine the features of the influence of forest ecosystems on the river runoff depending on the geophysical background

Altitudinal-belt variability of evapotranspiration of forest ecosystems in the mountains of Southern Siberia

This work is devoted to the study of evapotranspiration in the landscape complexes of the northern macroslope of the Western Sayan. Article summarizes literature and authors’ data on evapotranspiration obtained at experimental watersheds in the basin of the river Kebezh, on one of which in the 70s, as an experiment, 50 % of the forest area in the watershed has been cut down. Calculations of the total evaporation of phytocenoses at the basin level has been made, taking into account the altitudinal zonality. To calculate evapotranspiration at the study sites, field data obtained as a result of silvicultural and geobotanical studies and hydrological observations were used. Based on interpretation of remote sensing images and the use of digital elevation model, classification of landscape-hydrological complexes for the basins of the Kebezh and Taigish rivers was carried out, for which the components of evapotranspiration were calculated. The results showed that evapotranspiration in the dark coniferous taiga of the Western Sayan is an important component of the water balance and a significant proportion is the unproductive consumption of moisture for the evaporation of precipitation intercepted by tree crowns. It has also been established that the structure of evapotranspiration changes along the altitudinal zones in accordance with the vertical differentiation of climatic parameters and vegetation productivity. Estimated evapotranspiration data for various landscape-hydrological complexes made it possible to an indirect estimates of their contribution to the formation of runoff in river basins. This study can serve as a theoretical guide for landscape hydrological studies in the temperate cool zone

The influence of the LED lighting on structural-functional parameters of lettuce plants

Comparative studies were conducted on morphofunctional parameters of lettuce (Lactuca sativa) plants cultivated with the use of supplementary lighting from different light sources - LED lamps, high-pressure mercury arc lamp (HPM) and high-pressure sodium arc lamp (HPS). The work showed that morphofunctional parameters of lettuce were significantly higher with LED lighting, in comparison to plants cultivated with HPM illumination, and main parameters of leaves grown under LED were barely discernible from the samples grown under HPS lighting. We observed accelerated transfer into reproductive period during HPM lighting, what can lead to quality degradation of the product. Considering the approximate values of leaf character range in experiments with HPS and LED lighting and greater energy efficiency of LED, light emitting diodes are obviously more promising for supplementary illumination in protected ground conditions

Transformation of river runoff in permafrost zone of the Central Siberia under various scenarios of forest cover and climate change

The rise in air temperature that has taken place in recent decades both globally and on the territory of the Russian Federation has an impact on many environmental processes, including the hydrological regime of rivers. According to the data of meteorological stations for 1952–2012, the change in the main climatic indicators in the studied territory of the Central Siberia was estimated. Analysis of meteorological data confirms that over the past decades, there has been a change in the average annual air temperature. Changes of air temperature in the study area are characterized by a stable tendency to warming at a rate of 0.26–0.36 °С/10 years. The average air temperatures for the warm (V–IX) and cold (X–IV) months have a positive tendency to increase. Based on cartographic materials and satellite images, data on dynamic of forest cover were obtained for nine catchments located within three landscape zones – forest-tundra, northern and middle taiga. A regional model of the relationship between river runoff with forest cover of catchments, geographical coordinates and average annual air temperature was development. Numerical experiments with the obtained model showed that an increase in the forest cover of the river catchments in northern latitudes contributes to an increase in the annual runoff, and in southern regions, to its decrease. The results obtained can serve as a theoretical basis for a sustainable forest management in order to obtain the desired hydrological effect

Modeling air temperature changes in Northern Asia

Based on time series (1950-2005) of monthly temperatures from 73 weather stations in Northern Asia (limited by 70-180 degrees EL and 48-75 degrees NL) it is shown that there are statistically significant spatial differences in character and intensity of the monthly and yearly temperature trends. These differences are defined by geomorphological and geographical parameters of the area including exposure of the territory to Arctic and Pacific air mass, geographic coordinates, elevation, and distances to Arctic and Pacific oceans. Study area has been divided into six domains with unique groupings of the temperature trends based on cluster analysis. An original methodology for mapping of temperature trends has been developed and applied to the region. The assessment of spatial patterns of temperature trends at the regional level requires consideration of specific regional features in the complex of factors operating in the atmosphere-hydrosphere-lithosphere-biosphere system

Impact of Forest Harvesting and Forest Regeneration on Runoff Dynamics at Watersheds of Central Siberia

In the paper disturbance of Angara river region forests were estimated and peculiarities of forest regeneration after logging and wild fires were analyzed. According to the landscape classification of the regional study, three groups of landscapes differencing on types of forest successions were developed. It was shown that water protective and water regulate functions of the Angara river region forests change under commercial forest harvesting. Comparisons of the inventory and hydrological data detected that hydrological consequences of commercial forest harvesting are dependent on climatic parameters and forest regeneration peculiarities. In the continental climate conditions, when forest regeneration is delayed, snow storms are more active, snow evaporation increases and runoff reduces. In the process of logging sites overgrown with secondary small-leaved forest, snow accumulation increases and runoff increases, exceeding the value of annual runoff at undisturbed watersheds

New look at understanding hydrological role of forest

The article is concerned with the discussion of the reasons for the contradictions existing in the assessment of the hydrological role of forests. The authors believe that the accumulation of new information related to seemingly well-studied processes and phenomena necessitates revisions of traditional views and leads to new knowledge of the hydrological role of forests. Various conceptual approaches to assessing the hydrological role of forests in different geographic conditions are considered. System analysis of the materials obtained by the authors and literature data made it possible to identify the features of the hydrological cycle depending on the structure of forests and climatic conditions. The data of 460 snow surveys in the period of maximum snow reserves in 212 forest stands growing in different climatic and ecological conditions were used. The comparison of the features of snow moisture balance of the forest and treeless ecosystems in different climatic conditions contributed to understanding the reasons for the contradictory assessments of the hydrological role of forests. The authors showed that in the conditions of mild and warm winters, forests are more powerful evaporators of snow moisture than treeless sites and in conditions of severe winters with frequent snowstorms, they are the accumulators of snow moisture and sources of river flow. The paper presents a conceptual model describing the mechanisms of water cycle in the forests of the boreal zone, which determine the features of the influence of forest ecosystems on the river runoff depending on the geophysical background. Статья посвящена раскрытию причин противоречий, существующих в оценке гидрологической роли лесов. Авторы утверждают, что накопление новой информации в отношении, казалось бы, хорошо изученных процессов и явлений обусловливает необходимость пересмотра традиционных взглядов и приводит к получению новых знаний о гидрологической роли лесов. Рассмотрены разные концептуальные подходы к оценке гидрологической роли лесов в различных географических условиях. Системный анализ собственных материалов и литературных данных позволил выявить особенности гидрологического цикла в зависимости от структуры лесов и климатических условий. В работе использованы данные 460 снегосъемок в период максимальных снегозапасов в 212 насаждениях, произрастающих в неодинаковых климатических и лесорастительных условиях. Сопоставление особенностей баланса снеговой влаги лесных и безлесных экосистем в несхожих климатических условиях позволило понять причины противоречивых оценок гидрологической роли лесов. Авторы показали, что в условиях мягких и теплых зим леса по сравнению с безлесными пространствами являются более мощными испарителями снеговой влаги, а в условиях жестких зим с частыми метелями - накопителями снеговой влаги и источниками формирования стока рек. В работе представлена концептуальная модель, описывающая механизмы влагооборота в лесах бореальной зоны, которые определяют особенности влияния лесных экосистем на речной сток в зависимости от геофизического фона

Photomorphogenesis of wheat sprouts with LED irradiation of different intensities

Definition of the growth and development characteristics of plants in varied light conditions is a key factor for the creation of highly efficient light facilities for plant cultivation. Experimental research was conducted using an LED irradiation facility with photosynthetic photon flux densities ranging from 0 to 261 lmol m2 s1 and a continuous spectrum with maxima at 445 and 600 nm. Under the maximum photosynthetic photon flux density (261 lmol m2 s1) wheat germs demonstrated diminishing leaf surface with high values of specific leaf area, enhanced pubescence of ground tissues, increases in the number of stomata on the upper epidermis and palisade, and an increase in the thickness of the leaves as well as an increase in carotenoids but a decrease in the chlorophyll aþb/carotenoids relation. It was revealed that the optimum level of photosynthetic photon flux density for the referred spectrum was in the range from 82 to 100 mmol m2 s1, which may enable a reduction of irradiance under specific conditions during early development with no harm to the plants while minimizing energy consumption during cultivation