Effects of snow manipulation on larch trees in the taiga forest ecosystem in northeastern Siberia

Changes in winter precipitation (snow) may greatly affect vegetation by altering hydrological and biochemical processes. To understand the effects of changing snow cover depth and melt timing on the taiga forest ecosystem, a snow manipulation experiment was conducted in December 2015 at the Spasskaya Pad experimental larch forest in Eastern Siberia, which is characterized by a continental dry climate with extreme cold winters and hot summers. Variables including soil temperature and moisture, oxygen and hydrogen isotope ratios of soil moisture and stem water, foliar nitrogen and carbon contents and their isotopes, phenology, and soil inorganic nitrogen were observed at snow removal (SNOW−), snow addition (SNOW+), and CONTROL plots. After snow manipulation, the soil temperature at the SNOW− plot decreased significantly compared to the CONTROL and SNOW+ plots. At SNOW− plot, snowmelt was earlier and soil temperature was higher than at other plots during spring because of low soil moisture caused by less snowmelt water. Despite the earlier snowmelt and higher soil temperature in the SNOW− plot in the early growing season, needle elongation was delayed. Leaf chemistry also differed between the CONTROL and SNOW− plots. The needle nitrogen content in the SNOW− plot was lower in the middle of July, whereas no difference was observed among the three plots in August. The soil inorganic nitrogen content of each plot corresponded to these results. The amount of soil ammonium was lower in the SNOW− plot than in the other plots at the end of July, however, once production started in August, the amount of soil ammonium in the three plots was comparable. Extremely low soil temperatures in winter and freeze–thaw cycles in spring and dry soil condition in spring and early summer at the SNOW− plot may have influenced the phenology and production of soil inorganic nitrogen.

Rut formation after the passage of logging machinery in spruce forests on binomial soils

Колейность, образующаяся при проходе лесозаготовительной техники во время разработки лесосек при рубке леса, является одним из негативных экологических последствий, связанных с нарушениями почвенно-растительного покрова вырубок, определяющим дальнейшую их реновацию. Негативное влияние от формирования колейности зависит от числа проходов техники и связано с почвенно-климатическими условиями. На опытно-производственном участке ООО «Двинлеспром», территориально расположенном в междуречье С. Двины и Пинеги (Архангельская область, северотаежный лесной район европейской части РФ), изучено влияние разного числа проходов (4, 8, 10) груженого форвадера Ponsse Buffalo King по волоку, не покрытому порубочными остатками. Исходный участок леса представлен ельником черничным V класса бонитета, произрастающим на подзолистой почве на двучленных отложениях, широко распространенных в регионе. На постоянных учетных площадках (20 x 5 м), заложенных в 3 повторениях, провели детальное изучение строения колей, в дне каждой колеи вскрыли почвогрунт и сделали описание горизонтов/слоев почвы, взяли ненарушенные образцы почвы с глубины 0–10 и 10–20 см для определения влажности и плотности сложения. Установлено, что число проходов более определяет глубину, чем ширину колей. Выявлено 6 типов нарушений почвенного покрова по строению почво-грунта на дне колеи, связанных с перемешиванием, сдвиганием и выносом на дневную поверхность оглеенных почвообразующих пород. Показана представленность типов строения дна колеи в зависимости от числа проездов груженого форвардера, а также различия в плотности сложения и влажности почво-грунта. Плотность сложения в толще 0– 20 см при увеличении числа проходов техники закономерно увеличивается до значений, соответствующих почвообразующим породам. При этом доля влаги в толще 0–10 см при увеличении числа проходов повышается, а в толще 10–20 см снижается. Заметные изменения изученных показателей достигаются при восьмикратном проезде груженого форвардера, что позволяет считать это число проездом максимально допустимым на подзолистых почвах на двучленных отложениях в северотаежном лесном районе. The ruts formed after the passage of logging machinery during logging operations are one of the negative environmental consequences associated with disturbances of the soil and vegetation cover of deforestation, which determines their further renovation. The negative impact of the formation of ruts depends on the number of passes of machinery and is associated with soil and climatic conditions. We studied the effect of different number of passes (4, 8, 10) of a loaded Ponsse Buffalo King forvader on a skid trail that is not covered by felling residues. The experimental logging site of LLC Dvinlesprom is located in the watershed between of the Northern Dvina and Pinega (Arkhangelsk region, North Taiga forest region of the European part of the Russian Federation). The original site is represented by a blueberry spruce forest of the V class of bonity, which grows on podzolic soil on binomial deposits and is widely distributed in the region. We laid the permanent accounting pads (20 x 5 m) in 3 repetitions. We conducted a detailed study of the structure of the ruts, at the bottom of each rut, we opened the soil and made a description of the horizons/layers of the soil, took undisturbed soil samples from a depth of 0–10 and 10–20 cm to determine the soil bulk density and moisture content. It was found that the number of passes determines the depth more than the width of the ruts. We identified 6 types of disturbances of the soil cover on the structure of the soil at the bottom of the ruts, associated with mixing, shifting and removal of the gleying soil-forming parent soil to the day surface. We have given the types of the structure of the bottom of the ruts depending on the number of passes of the loaded forwarder, as well as the differences in the soil bulk density and moisture content. The soil bulk density in the thickness of 0–20 cm with an increase in the number of passes of the forwarder naturally increases to the values corresponding to the soil-forming parent soil. At the same time, the proportion of moisture in the thickness of 0–10 cm increases with an increase in the number of passes, and in the thickness of 10–20 cm decreases. Noticeable changes in the studied indicators are achieved with an eight-fold passage of a loaded forwarder, which allows us to consider this number as the maximum permissible passage on podzolic soils on binomial deposits in the north taiga forest area.

Water vole (Arvicola amphibious) as an object of long-term biomonitoring in a floodplain area (Western Siberia, Russia)

The paper is devoted to the dynamics of the water vole population in the conditions of total deforestation of valley forests and their subsequent restoration. We analyzed the relative population of small mammals in the typical biotopes in the Tom River basin (Western Siberia) on the border of the forest-steppe and taiga zones. From 1978 to 2019, 1,139 water voles Arvicola amphibius (Linnaeus, 1758) (synonym of A. terrestris) were caught with 50-meter trapping grooves; for 788 individuals we assessed the condition of non-metric features (phenes) of the skull. It was found that changes in the population level are non-cyclical, while against the background of a generally low occurrence of the species in the region, the population level increased tenfold in some years. It was shown that such episodic population surges can significantly impact the structure of the community of small mammals. In the valley of the Tom River, the water vole prefers inhabit wet meadows and ecotone areas between the meadow and the dark coniferous taiga forest. During the years of population surges, the water vole intensely occupies new nesting sites due to the dispersal activity of young animals but at the same time retains the original biotopic preferences. Dispersal of the species takes place in waterlogged wetlands. Most of the animals caught during the peak of their numbers were young animals of late broods born from overwintered individuals. The conducted phenetic analysis revealed the heterogeneity of young animals during the population surge, which allowed us to assume the participation of several populations in the formation of the peak. In the final surge year, the surge was characterized by an extremely low percentage of participation in the breeding of young females and the appearance of a large number of weakened animals, which led to crisis in the species population and the disappearance of the water vole from the captures. The research shows that one cannot predict the success of this process at the current stage; therefore, after flooding, it is necessary to continue monitoring.

Forestry and taxation characteristics of Spruce (Piceetum oxalidosum) stands in Udmurt Republic

The results of a forestry and taxation study of spruce stands of the acidic type of two forest districts of the Udmurt Republic are presented. The death of the most productive spruce individuals (productivity class I–II according to B.D. Zhilkin) and pure spruce plantations (acidic forest types, I–II class of bonitet) was noted due to the mass spread of bark beetle typographus (Ips typographus). The most extensive processes of shrinking of plantings were noted in the forest area of coniferous-deciduous forests of Udmurtia. A decrease in completeness in some areas of spruce stands to 0,1...0,3 was revealed, as well as the accumulation of large volumes of dead wood. A change in environmental conditions was revealed due to a decrease in completeness in spruce stands, which led to the development of field grasses and the growth of soft-leaved species. Despite the fact that the peak of the bark beetle development occurred in 2013, a gradual expansion of its range was revealed both in the forest area of coniferous-deciduous forests and in the south taiga forest area of the Udmurt Republic.

Carbon stock in litter of middle taiga forest ecosystems of Central Siberia

Litter plays an important role in the carbon cycle of forest ecosystems incorporating significant amount of carbon as a result of annual partial die-off of the biomass and releasing it during complex multistage processes of organic matter decomposition. The balance of these processes in the forests of permafrost zone significantly shifts towards the accumulation of dead organic matter. That makes the assessment of litter stock in these ecosystems particularly relevant, especially in relation to the predicted consequences of climate change in the study region. On the territory of middle taiga of Central Siberia, 14 sampling plots were established in the various landforms (slopes of different exposition, lowlands and uplands). The carbon stock in litter of the main forest types of the studied area varied from 0.47 to 4.46 kgC/m2. Also, the paper considers composition of litter accumulated in these ecosystems, including the ratio between fresh litterfall, fermented and humified plant residues, and dead roots. Our results demonstrated that fermented plant residues prevailed in the litter composition in most types of studied forest ecosystems due to specificity of hydrothermal regime and quality of litterfall. The results obtained might be applied to refine the carbon budget of Siberian forests.

Effects of Snow Manipulation on Larch Trees in the Taiga Forest Ecosystem in Northeastern Siberia

Changes in winter precipitation (snow) may greatly affect vegetation by altering hydrological and biochemical processes. To understand the effects of changing snow cover depth and melt timing on the taiga forest ecosystem, a snow manipulation experiment was conducted in December 2015 at the Spasskaya Pad experimental larch forest in Eastern Siberia, which is characterized by a continental dry climate with extreme cold winters and hot summers. Variables including soil temperature and moisture, oxygen and hydrogen isotope ratios of soil moisture and stem water, foliar nitrogen and carbon contents and their isotopes, phenology, and soil inorganic nitrogen were observed at snow removal (SNOW−), snow addition (SNOW+), and CONTROL plots. After snow manipulation, the soil temperature at the SNOW− plot decreased significantly compared to the CONTROL and SNOW+ plots. At SNOW−, snowmelt was earlier and soil temperature was higher than at other plots during spring because of low soil moisture caused by less snowmelt water. Despite the earlier snowmelt and higher soil temperature in the SNOW− plot in the early growing season, needle opening and shoot elongation were delayed. Leaf chemistry also differed between the CONTROL and SNOW+ plots. The needle nitrogen content in the SNOW− plot was lower in the middle of July, whereas no difference was observed among the three plots in August. The soil inorganic nitrogen content of each plot corresponded to these results. The amount of soil ammonium was lower in the SNOW− plot than in the other plots at the end of July, however, once production started at the end of August, the amount of soil ammonium in the three plots was comparable. Extremely low soil temperatures in winter and freeze-thaw cycles in spring at the SNOW− plot may have affected these results.

General assessment of natural reforestation by the prevailing species, types of forest and types of growing conditions on the territory of the Lisinsky part of the Leningrad Region Training and Experimental Forestry

Целью исследования являлось изучение естественного лесовозобновления в условиях средней тайги таежной лесорастительной зоны РФ на основе массовых данных лесоустройства, в которых отражена информация о ходе естественного лесовозобновления. Поставленная задача была решена с помощью электронной повыдельной базы данных объекта исследования, включающая в себя информацию, необходимую для общей оценки подроста хозяйственно ценных пород. Оценка естественного лесовозобновления была проведена по шкале оценки возобновления. Из общей электронной базы были отобраны все выделы естественного происхождения в возрасте преобладающей породы основного яруса старше 4-го класса возраста, т. е. хвойные старше 80 лет и мягколиственные старше 40 лет. Общий объем выборки составил 6533 выдела площадью 16814,2 га. В целом на 32,7% площади таксационных выделов, наблюдается полное отсутствие подроста хозяйственно ценных пород. Структура породного состава подроста характеризуется практически полным доминированием елового подроста. Оптимальные условия для естественного лесовозобновления ели создаются в черничниках (встречаемость 99,8%) и в кисличниках – встречаемость 98,4%. Максимальный процент подроста с оценкой хорошо по преобладающей на выделе древесной породе (35% от всех выделов с подростом) оказался в сосняках кисличного типа леса в свежих суборях. The aim of the study was to study natural reforestation in the middle taiga of the taiga forest zone of the Russian Federation on the basis of mass forest management data, which reflects information about the progress of preliminary reforestation. The task was solved with the help of an electronic database of the research object, which includes the information necessary for the overall assessment of the undergrowth of economically valuable breeds. The assessment of natural reforestation was carried out on the basis of the renewal assessment scale. From the general electronic database of data, all natural-origin selections were selected at the age of the predominant breed of the main tier older than the 4th age class, i.e. coniferous over 80 years old and softleaved over 40 years old. The total sample size was 6,533 allotments with an area of 16,814. 2 hectares. In general, on 32.7% of the area of taxation allotments, there is a complete absence of undergrowth of economically valuable breeds. The structure of the breed composition of the undergrowth is characterized by almost complete dominance of spruce undergrowth. Optimal conditions for the natural reforestation of spruce are created in blueberry forests (99.8% occurrence) and in acid forests-98.4% occurrence. The maximum percentage of undergrowth with a rating of good for the wood species prevailing in the allotment (35% of all allotments with the adolescent) was found in the pine forests of the acidic forest type in fresh sub-forests.

TBE in Russia

TBE was first revealed in the Far-East Taiga Forest in the Soviet Union in springs and summers between 1933-19351 and it was further investigated as of 1937 at a large multidisciplinary expedition led by Professor Lev Zilber, the Head of the Moscow Medical Virology laboratory.2,3 The expedition demonstrated that the disease develops in humans after a tick bite,4 and the “Taiga Tick” Ixodes persulcatus was established as the virus carrier. The viral etiology of the disease was confirmed and the first strain of TBE virus (TBEV) was isolated. The clinical disease spectrum in humans and the respective pathology were described and the effectiveness of immunoglobulin-therapy was shown.5 Based on morphological studies since 1937 TBE was assigned to the group of neuro-infections as an independent nosological entity.6,7

FORESTRY EVALUATION OF GROWTH OF FOREST CROPS OF SPIRIT CREATED BY DIFFERENT TYPES OF PLANTING MATERIAL

The purpose of the scientific article is to assess the growth and condition of forest crops of European spruce, created by various types of planting material. The planting of European spruce seedlings in the southern taiga forest area was studied, their survival rate was assessed, and a comparative analysis of the growth of forest crops created by planting material with a closed root system and planting material with open roots was performed.