Study relevance and goals. Soil is one of the key pools of carbon in terrestrial ecosystems. According to recent data, the soil carbon pool of forest ecosystems may be significantly underestimated. Therefore, obtaining data on the forest soil carbon with reliable interpolation on geographic area contours is of particular interest. In the present work, the available data on soil carbon stocks are aggregated in accordance with forested regions: officially approved ecological administrative spatial units. Forested regions serve as a topological basis for the extrapolation of sample set data to the entire territory of the corresponding region and forest lands in general. The immediate goal of this work is to interpolate data from soil profiles by layers of the soil stratum in forest regions. Study objects and methods. The basis for calculating the carbon stocks in the forest and tundra soils of Russia is a database that combines information on soil sections gathered from a total of 300 literary sources. To determine the spatial differentiation of the mean values, all the sections present in the database are assigned to different forested regions according to their coordinates. For each section, we determine a forested region and a habitat on the basis of the description of the section. A total of 1405 soil sections are selected containing all the data necessary for the analysis: coordinates, calculated data on the carbon content at various soil levels, and data on the habitat in which the section is made. Study results. The regression analysis of the correlation between soil carbon stocks and habitats and soil carbon stocks and the forested regions confirm the selected cartographic basis for the interpolation to be a good fit, which confirms the validity of the choice of the topological basis for soil data interpolation. The total and mean reserves of soil carbon are obtained for an area of 1368 × 10 6 ha of forest regions in Russia. Conclusions. The total C soil stock for the territory of Russia within the layers of 0–30, 0–50, and 0–100 cm is estimated at 128.4 × 10 9 t C, 166.5 × 10 9 , and 215.8 × 10 9 t C. For the layer of 0–100 cm, the mean reserves are 162 ± 23 t C ha –1 , represented by mean values ± SE (standard error). Maps of the distribution of carbon stocks for the forested regions of Russia are obtained in relation to different depths of the sections.

Soil carbon pool in the block of the European-Ural part of Russia was assessed on a topological basis of lands categories adopted in State Forest Inventory (21 biotopes in total). The published data on 675 soil profiles were linked to biotopes and forest regions through coordinates and descriptions of profiles (13). The total carbon stock in the soils in forest regions of the European-Ural part were 19.3*109 t C for a depth of 0–30 cm, 26.6*109 t C for a depth of 0–50 cm, and 34.2*109 t C for a depth of 0–100 cm. Forest area in the European part of Russia for these forest regions is estimated at 181.13*106 ha. Aggregated data are presented both for biotopes of the entire region and for forest regions. We compared the results obtained on top basis of dominant tree species and non-forest lands with the estimates of other authors obtained for various soil types.

The carbon pool of the soil block of the European-Ural part of Russia was estimated on the basis of land categories adopted in the State Forest Register (21 biotopes in total). Published data of 675 soil sections using the coordinates and descriptions of sections were linked to biotopes and forest areas (13). The total carbon stock in the soils of forest regions of the European-Ural part amounted to 19.3 *109 t C for a depth of 0-30 cm, 26.6 *109 t C for a 0-50 cm depth, and 34.2 *109 t C for 0-100 cm. The total area of the forest sector in the European part of Russia for these forest regions is estimated at 181.13 *106 ha. Aggregated data are given both for biotopes of the entire region and for forest areas. The results we obtained on a top basis of forest-forming species and non-forest lands are compared with estimates of other authors obtained for various types of soils.

According to the data of the State Forest Registry and the archive materials of the State Forest Fund Account carbon budget of the forests of federal districts (FDs) of Russia was calculated for the years 1988–2015. The total carbon pool of the forested lands of Russia amounted to 123.77±18.93 Gt C as of 01.01.2015. The biggest contribution to the national forest carbon pool was made by Siberian (36.4%) and the Far Eastern (35.2%) FDs followed by the Northwestern (11.3%), Ural (9.3%), Volga (4.4%), the Central (2.8%), North Caucasian (0.3%) and the Southern (0.2%) FDs. Contribution to the national forest carbon sink (206.10±66.86 Mt C yr -1) by districts: the Siberian district 39.3%, the Far Eastern 15.1%, the Northwestern 12.4%, Volga 12.1%, Ural 11.0%, and the Central 8.8%. Two groups of districts stand out in terms of the average value of forest carbon sink: 1) with 0.64–0.85 t С ha-1 year-1 (the Central, the Southern, North Caucasian, Volga FDs), 2) with 0.11–0.33 t C ha-1 year-1 (the Northwestern, Ural, Siberian, the Far Eastern FDs). The magnitude of the carbon sink in the forests of the FDs was at its lowest in 1988–1993. The reduction of losses due to felling in 1993–2000 resulted in increased carbon sink in the majority of federal districts. According to the level of this increase the forests of FDs can be divided into 2 groups: 1) with a significant increase in carbon sink (by 86% and more) – the Northwestern, Ural, Siberian, the Far Eastern FDs; 2) with a moderate increase in carbon sink (by 4–46%) in the Central, the Southern, North Caucasian and Volga FDs.

The calculations of forest carbon budget of federal districts (FD) of Russia is performed using data of State forest registry and archive materials of state forest fund accounts. Total carbon reserves on forested lands of Russia at 01.01.2015 were 123.77±18.93 Gt C. The input to national forest carbon reserves were maximal in Siberian (36.4%) and Far East (35.2) FD. The next were North-West (11.3%), Ural (9.3%), Volga (4.4%), Central (2.8%), North-Caucasian (0.3%) and South (0.2%) FD. Inputs to national forest carbon sink (206.10±66.86 Mt C year-1) were by FD: Siberian 39.3%, Far East 15.1%, North-West 12.4%, Volga 12.1%, Ural 11.0%, Central 8.8%. Two groups of FD can be selected based on average carbon sink value: 1) with range 0.64-0.85 t C ha-1 year-1 (Central, South, North-Caucasian, Volga), 2) with range 0.11-0.33 t C ha-1 year-1 (North-West, Ural, Siberian, Far East). Carbon sink to forest of all FD was minimal in 1988-1993. The decrease of carbon losses with felling in 1993-2000 led to increase of carbon sink in majority of FD. FD can be subdivided by value of carbon sink increase on 2 groups: 1) with considerable increase (more then 86%) including North-West, Ural, Siberian, Far East; 2) with moderate increase (4-46%) including Central, South, North-Caucasian, Volga.

На основе системы РОБУЛ (региональная оценка бюджета углерода лесов) исследовали динамику углеродного баланса лесов России в 1988-2015 гг. Сток углерода (превышение поглощения над потерями) в леса был минимальным в 1988 г. С первой половины 1990-х годов начался его рост. Это увеличение было связано со снижением объёма лесозаготовок в связи с социально-экономическими реформами. После 2008 г. сток углерода стал постепенно снижаться, что было обусловлено увеличением потерь при рубках, от лесных пожаров и снижением поглощения углерода.

Regional Evaluation of Carbon Budget of Forests (RECBF), was used to study the dynamics of carbon balance in Russian forests in 1988–2015. The carbon sink (excess of absorption over losses) to forests was minimal in 1988. Since the first half of the 1990s, its increase has started. This increase was associated with the reduction of logging volume in connection with socioeconomic reforms. Since 2008, the carbon sink was gradually reduced due to increasing losses in logging operations, forest fires, and decreased carbon absorption.

The system for the regional assessment of a forest carbon budget is expanded with the procedures of uncertainty calculations. The forest carbon balance of the Russian Federation for 1988–2009 is assessed. The impact of fire on the forest carbon budget is estimated using both official statistics and remote sensing data. For the study period, the average carbon sink from the atmosphere to Russian forests was 205 ± 64 × 106 t C yr−1 on average, varying from 70 ± 81 × 106 t C yr−1 in 1998 to 287 ± 60 × 106 t C yr−1 in 2001. The interannual variations of carbon sink are determined by the dynamics of carbon losses due to forest fires. The distribution of the fireinduced carbon losses in Russian regions is examined using remote-sensing data.

ISSN: 0024-1148 Russian Journal of Forest Science. 2013, No. 5, pp. 36-49 THE IMPACTS OF FIRES AND CLEAR-CUTS ON THE CARBON BALANCE OF RUSSIAN FORESTS D. G. Zamolodchikov 1,2 , V. I. Grabovsky 2 , P. P. Shulyak 2 , O. V. Chestnykh 1 1 Lomonosov Moscow State University Leninskie Gory 1, Moscow, 119991, Russia 2 Center for Forest Ecology and Productivity of the Russian Academy of Sciences Profsoyuznaya st. 84/32 bldg. 14, Moscow, 117997, Russia E-mail: dzamolod@cepl.rssi.ru Received 1 March 2013 The system for the regional assessment of a forest carbon budget is expanded with the procedures of uncertainty calculations. The forest carbon balance of the Russian Federation for 1988–2009 is assessed. The impact of fire on the forest carbon budget is estimated using both official statistics and remote sensing data. For the study period, the average carbon sink from the atmosphere to Russian forests was 205 ± 64 × 10 6 t C yr −1 on average, varying from 70 ± 81 × 10 6 t C yr −1 in 1998 to 287 ± 60 × 10 6 t C yr −1 in 2001. The interannual variations of carbon sink are determined by the dynamics of carbon losses due to forest fires. The distribution of the fireinduced carbon losses in Russian regions is examined using remote-sensing data. Keywords: Russian forests, carbon balance, forest reserves, dynamics, phytomass, deadwood, litter, soil, clearcuts, forest fires, uncertainty, remote sensing.

A lot of studies on the impact of global climate changes on natural communities deal with cryogenic ecosystems, tundra in particular, since they are delimited by low air temperature and permafrost, thus being extremely sensitive to long-term climate fluctuations. Continuous warming in Northern Hemisphere is unmasking all the more details concerning complex system of direct relationships, feedbacks, and interactions of carbon balance factors as the main response function. While the set of such factors may be viewed as more or less complete, their relative contribution to C-balance, as is becoming clear with accumulating results of field observations, directly depends on temporal scale of observations and is not constant. As the results of field observations and modeling of tundra ecosystems show, any one of significant factors can become the leading one within the boundaries determined by the given scale of observations. Even the least significant factor can become the determining one for direction of carbon annual net flux in an ecosystem, if contributions of more significant factors canceled each other during the period of observations. In the most general situation, the greater is the variation of a significant factor during the period of observations, the larger is its partial contribution. The complete set of independent variables of C-balance is not limited by abiotic factors but should include such an important factor as a stock of plants living top mass, which can be treated as not only the natural product of C-balance but also as its independent parameter.

The state and results of studies on the carbon cycle of forests on lands of the Russian forest fund (total area 1172 × 106 ha) are analyzed at the federal level. Consideration is given to changes in the areas of different categories of forest lands, the age structure of stands, the pool and deposition of carbon in the phytomass, and the organic carbon pool of soils over the period from 1966 to 1998; the dynamics of activity in the forest industry by years and the extent of pyrogenic transformation of the forest cover between 1990 and 2001; and carbon fluxes associated with forest exploitation, including carbon emission resulting from fires.