Search

Quantitative assessments of the carbon balance of terrestrial landscapes and, specifically the permafrost zone, where the most significant warming trends are observed, require taking into account the export of terrigenous carbon beyond their boundaries with lateral flow. The paper presents the results of long-term monitoring of intraseasonal and interannual fluctuations in the concentrations of dissolved organic (DOC) and inorganic (DIC) carbon in the hydrographic network of the Central Siberian Plateau, carried out on the basis of the Evenkian field station of the V. N. Sukachev Institute of Forest, Siberian Branch, Russian Academy of Sciences (Tura settlement). Research is being carried out on more than 100 streams and rivers of various orders in the middle reaches of the Lower Tunguska River (62–66°N, 96–102°E) based on regular measurements of the concentrations of all forms of carbon, as well as quasi-continuous monitoring of the physical and chemical parameters using specific sensors and automatic loggers. It has been shown that the main limiting factors of lateral carbon flux within the Central Siberian Plateau at present are: 1) stocks of potentially mobilizeable organic carbon in terrestrial landscapes and 2) amount of precipitation in a sharply continental climate. An increase in the DOC flux is predicted both as a result of thawing of C-rich frozen deposits and an increase in the productivity of plant cover, and inorganic carbon – as a result of increased rates of silicate rock weathering and sequestration of atmospheric CO2. Negative predictions of DOC behaviour are associated with an increase in the depth of infiltration of solutes with an increase in the seasonally thawed soil layer, which determines the sorption of DOC in the soil column and its microbiological destruction. An increase in the area and intensity of fires as a result of climate warming determines a significant transformation of the lateral carbon flux. At the same time, the observed reduction in river flow as a result of an increase in the pyrogenic factor will determine the overall decrease in the transport of terrigenous carbon from terrestrial landscapes.

Despite recent progress in the understanding of the carbon (C) cycle of Siberian permafrost-affected rivers, spatial and seasonal dynamics of C export and emission from medium-sized rivers (50 000–300 000 km2 watershed area) remain poorly known. Here we studied one of the largest tributaries of the Ob River, the Ket River (watershed = 94 000 km2), which drains through pristine taiga forest of the boreal zone in the West Siberian Lowland (WSL). We combined continuous and discrete measurements of carbon dioxide (CO2) concentration using submersible CO2 sensor and floating chamber flux (FCO2), with methane (CH4), dissolved organic and inorganic C (DOC and DIC, respectively), particulate organic C and total bacterial concentrations over an 800 km transect of the Ket River main stem and its 26 tributaries during spring flood (May 2019) and 12 tributaries during summer baseflow (end of August–beginning of September 2019). The partial pressure of CO2 (pCO2) was lower and less variable in the main stem (2000 to 2500 µatm) compared to that in the tributaries (2000 to 5000 µatm). In the tributaries, the pCO2 was 40 % higher during baseflow compared to spring flood, whereas in the main stem, it did not vary significantly across the seasons. The methane concentration in the main stem and tributaries was a factor of 300 to 1900 (flood period) and 100 to 150 times lower than that of CO2 and ranged from 0.05 to 2.0 µmol L−1. The FCO2 ranged from 0.4 to 2.4 g C m−2 d−1 in the main channel and from 0.5 to 5.0 g C m−2 d−1 in the tributaries, being highest during August in the tributaries and weakly dependent on the season in the main channel. During summer baseflow, the DOC aromaticity, bacterial number, and needleleaf forest coverage of the watershed positively affected CO2 concentrations and fluxes. We hypothesize that relatively low spatial and seasonal variability in FCO2 of the Ket River is due to a flat homogeneous landscape (bogs and taiga forest) that results in long water residence times and stable input of allochthonous dissolved organic matter (DOM), which dominate the FCO2. The open water period (May to October) C emission from the fluvial network (main stem and tributaries) of the Ket River was estimated to 127 ± 11 Gg C yr−1, which is lower than the downstream dissolved and particulate C export during the same period. The estimated fluvial C emissions are highly conservative and contain uncertainties linked to ignoring hotspots and hot moments of emissions, notably in the floodplain zone. This stresses the need to improve the temporal resolution of FCO2 and water coverage across seasons and emphasizes the important role of WSL rivers in the release of CO2 into the atmosphere.

Greenhouse gas (GHG) emission from inland waters of permafrost-affected regions is one of the key factors of circumpolar aquatic ecosystem response to climate warming and permafrost thaw. Riverine systems of central and eastern Siberia contribute a significant part of the water and carbon (C) export to the Arctic Ocean, yet their C exchange with the atmosphere remains poorly known due to lack of in situ GHG concentration and emission estimates. Here we present the results of continuous in situ pCO2 measurements over a 2600 km transect of the Lena River main stem and lower reaches of 20 major tributaries (together representing a watershed area of 1 661 000 km2, 66 % of the Lena's basin), conducted at the peak of the spring flood. The pCO2 in the Lena (range 400–1400 µatm) and tributaries (range 400–1600 µatm) remained generally stable (within ca. 20 %) over the night–day period and across the river channels. The pCO2 in tributaries increased northward with mean annual temperature decrease and permafrost increase; this change was positively correlated with C stock in soil, the proportion of deciduous needleleaf forest, and the riparian vegetation. Based on gas transfer coefficients obtained from rivers of the Siberian permafrost zone (k=4.46 m d−1), we calculated CO2 emission for the main stem and tributaries. Typical fluxes ranged from 1 to 2 gCm-2d-1 (>99 % CO2, % CH4), which is comparable with CO2 emission measured in the Kolyma, Yukon, and Mackenzie rivers and permafrost-affected rivers in western Siberia. The areal C emissions from lotic waters of the Lena watershed were quantified by taking into account the total area of permanent and seasonal water of the Lena basin (28 000 km2 ). Assuming 6 months of the year to be an open water period with no emission under ice, the annual C emission from the whole Lena basin is estimated as 8.3±2.5 Tg C yr−1, which is comparable to the DOC and dissolved inorganic carbon (DIC) lateral export to the Arctic Ocean.

Possibility is considered for improvement of fire protection in larch forests of the Kazakhstan Altai. It is proposed to predict the occurrence of fires and their behavior based on vegetation fuel maps using the computer program for predicting vegetation fire behavior, including fire spread rate, development, immediate effects and assessment of manpower and means to suppress the fire. The vegetation fuel maps (VF maps) are based on the pyrological description of forest types and other categories of sites, as well as on the VF classification developed at the V. N. Sukachev Institute of Forest, Russian Academy of Sciences, Siberian Branch. Vegetation of the Kazakhstan Altai has never been described this way before. For the first time, the larch forest types of this region have been analyzed in terms of the types of primary fire carriers (PFC types), thus making it possible to predict flammability of vegetation plots taking into account weather dynamics. The PFC types in the Kazakhstan Altai larch forests have been identified by analyzing regional descriptions of forest types present in the forestry inventory plan. There is a brief description of the computer programs for making VF maps (PGM) and for predicting fire spread rate, intensity, development and effects (PGM2). A performance test is given to both programs on the example of the Markakolsky Forestry District: examples of VF maps for different periods of the fire season are given and behavior of a conditionally specified surface fire is analyzed. The use of these developments in practice will significantly increase the efficiency of firefighting equipment and financial means, as it will contribute to making optimal decisions in cases of several fires being active and insufficient fire suppression means and manpower available. In some cases, behavior prediction of active fires may prove that there is no need to immediately suppress them.

For the mountain profile of the Western Sayan located in the south of the Krasnoyarsk Krai, the recreational value of forest areas was assessed according to such characteristics as landscape-aesthetic value, stability, forest health and hygienic effect, digression, assessment of the types of sites. The estimation of recreational resource of the territory is given according to the typology of tourist forest use: the functions of tourist forest use, the motivation of tourist behavior and the types of tourist recreation. Recreational and touristic characteristics and landscape-aesthetic value of natural complexes are estimated in relative units. Specially Protected Natural Areas are given as examples of objects in which recreational activities are conducted. A landscape approach was used with the allocation of altitude-belt complexes and their characteristics in terms of climatic indicators, biodiversity, seasonal aspectivety, which made it possible to estimate territories from the point of view of recreational forest use and perspectives of recreation and tourism. The complex of studies made it possible to assess the recreational potential of mountain forest areas and determine their functional feasibility for existing and prospective types of recreation and tourism.

Wildland fires distribute unevenly in time and over area under the influence of weather and other factors. It is unfeasible to air patrol the whole forest area daily during a fire season as well as to keep all fire suppression forces constantly alert. Daily work and preparedness of forest fire protection services is regulated by the level of fire danger according to weather conditions (Nesterov’s index. PV-1 index), fire hazard class (Melekhov’s scale), regional scales (earlier called local scales). Unfortunately, there is still no unified comparable technique of making regional scales. As a result, it is difficult to maneuver forest fire protection resources, since the techniques currently used are not approved and not tested for their performance. They give fire danger rating incomparable even for neighboring regions. The paper analyzes the state-of-the-art in Russia and abroad. It is stated the irony is that with factors of fire danger measured quantitatively, the fire danger itself as a function has no quantitative expression. Thus, selection of an absolute criteria is of high importance for improvement of daily fire danger rating. On the example of the Chunsky forest ranger station (Krasnoyarsk Krai), an improved technique is suggested of making comparable local scales of forest fire danger rating based on an absolute criterion of fire danger rating – a probable density of active fires per million ha. A method and an algorithm are described of automatized local scales of fire danger that should facilitate effective creation of similar scales for any forest ranger station or aviation regional office using a database on forest fires and weather conditions. The information system of distant monitoring by Federal Forestry Agency of Russia is analyzed for its application in making local scales. To supplement the existing weather station net it is suggested that automatic compact weather stations or, if the latter is not possible, simple weather observation points should be organized in forest ranger stations and aviation bases for obtaining up-to-date weather information.

An algorithm of forest cover mapping based on combined GIS-based analysis of multi-band satellite imagery, digital elevation model, and ground truth data was developed. Using the classification principles and an approach of Russian forest scientist Kolesnikov, maps of forest types and forest growing conditions (FGC) were build. The first map is based on RS-composite classification, while the second map is constructed on the basis of DEM-composite classification. The spatial combination of this two layers were also used for extrapolation and mapping of ecosystem carbon stock values (kgC/m2). The proposed approach was applied for the test site area (~3600 km2), located in the Northern Siberia boreal forests of Evenkia near Tura settlement.

A technique of conjugate analysis of dissimilar data in a stepwise manner for spatial modeling of potential forest growing conditions and forest regeneration dynamics was developed using standard software (ArcGIS, ERDAS). This algorithm involves spatial analysis of multi-band satellite data, a digital elevation model, and ground measurements. Based on this algorithm, maps reflecting the diversity of forest growing conditions and forest regeneration series and stages were developed to south central Siberia.