1. Reserves and Density of Organic Carbon in Russian Forests Anatoly Utkin, Dmitry Zamolodchikov, Georgy Korovin and Olga Chestnykh 4. C phytomass and forest-forming species. Within the total reserve of C phytomass in forests (31.42 x 10 9 t C) 77% is coniferous, 4% is hardwood deciduous, 15% is softwood deciduous, and 4% is other tree and shrub species, including 3.4% of shrub stands of dwarf Siberian pine (while they occupy 5.4% of lands). The distribution of C soil is 69% coniferous, 3% hardwood deciduous, 15% softwood deciduous, and 13% other. Reserves of C phytomass for separate forest-forming species are estimated by occupied areas (Fig. 3). Larch, pine, spruce, and birch stands occupy 77% of forest area within SFR, 77% of C phytomass, and 70% of C soil (Fig. 3). Fig 1. Distribution of the total area of SFR by lands groups for four macroregions and three landscape subzones, 10 6 ha. 5a. Geographic variability of C phytomass and C soil density within SFR of Russia. The values of carbon density for both pools are estimated for ecoregions and federal districts of RF. They indicate the clear relationships. The density of C phytomass increases in the southward direction (Fig. 4), whereas it decreases slightly in the same direction for C soil (Fig. 5). The density of C soil depends significantly on the carbon reserve of non-forest lands, peat bogs first of all. 5b. The density of C phytomass and C soil. The averaged density of C total for SFR is 186 t ha -1, varying from 170 to 205 t ha -1 for four macroregions, and from 179 to 202 t ha -1 for three landscape subzones. Fig. 4. Geographic distribution of C phytomass density within SFR of Russia. Fig 5. Geographic distribution of C soil density within SFR of Russia. 6. Deposition of C phytomass in SFR of Russia. The averaged annual deposition of C is estimated as difference between reserves of C phytomass in stands of adjacent age groups. The geographic relationships of deposition are similar to distribution of density (Fig. 6 and Fig. 4). Deposition depends on stand age and peaks in young and middle-aged forests (Fig. 7). Young and middle-aged stands account for 51% of the total forest area in the European part of Russia. Nearly the half (44%) of C for all SFR of Russia is deposited here. It is 243.16 x 10 6 t C year -1 for forests and 261.64 x 10 6 t C year -1 for all areas of SFR. Fig. 6. Geographic distribution of deposition of C phytomass density within SFR of Russia. Fig. 7. Annual deposition of C phytomass in stands of different age groups within SFR for four macroregions of Russia. The estimates of annual deposition per SFR area are averaged for Russia as 315 kg C ha -1 year -1 in forests and 221 kg C ha -1 year -1 on all lands. These values are, respectively, 656 and 544 kg C ha -1 year -1 for the European part, 233 and 148 kg C ha -1 year -1 for the Western Siberia, 254 and 202 kg C ha -1 year -1 for the Eastern Siberia, 191 and 121 kg C ha -1 year -1 for the Far East. 7. Conclusion. At the area of SFR of Russia the forest cover percent is 45.3%, the bog cover percent is 11.5%, reserves of C phytomass and C soil are, respectively, 34.35 x 10 9 and 172.43 x 10 9 t C. The reserve of C in coarse wood debris (C c.w.d. ) is tentatively estimated as 2.40 x 10 9 t C. When C c.w.d. was being estimated, it was taken that the reserve of dead standing trees and windfall in forests is about 30% of living trees, and the wood density C c.w.d. for various species is 50% of the initial value. Consequently, C total in SFR of Russia is 209.18 x 10 9 t C by the averaged density about 190 t C ha -1, if C c.w.d. is taken into account. C soil is the greatest of all carbon pools. Therefore particular attention must be given to C soil when the dynamics of boreal forests is modeled. Forests of the European part of Russia belong to carbon-deposing ecosystems, whereas forests of Siberia and the Far East are, in contrast, carbon-conserving ecosystems. Dominance of mature and over-mature stands within the last ones can become an obstacle for reaction of local forest ecosystems to global climate change. Fig 2. Distribution of C phytomass in forest and C soil in different land groups of SFR for four macroregions and three landscape subzones, 10 9 t C. 2. Areas of lands in SFR. The total area of SFR is composed of forests - 64%, altered forests (burned areas, clearcuts, etc.) - 10%, and non-forest lands - 26%. The last ones increase in east- and northward directions (Fig.1). 3. Resources of C phytomass and C soil in SFR lands. C phytomass of all lands in SFR is 34.35 x 10 9 t C, 98% of it is accounted for forests (Fig.2), whereas C phytomass of two other groups is 1% for each. C soil of SFR is five times greater than C phytomass and is distributed between forests (61%), altered forests (8%) and non-forest lands (31%) (Fig.2). The percentage relation between the northern, middle, and southern landscape subzones is 25:39:36 for C phytomass and 45:32:23 for C soil..Introduction. The area of State Forest Reserves (SFR) of Russian Federation (RF) is 1110.5 x 10 6 ha. The 99% of the area falls on boreal forests. It is important to have corresponding data on carbon resources in phytomass (C phytomass ), soil (C soil ) and in these two pools together (C total ) when modelling forest dynamics in RF in connection with the global climate change. Estimations are made for three landscape subzones and four macroregions after data for 59 ecoregions in the Asian part and for 56 subjects of federation in the European part of Russia. Next data bases were used: a) state forest inventory; b) phytomass estimations for forest stands; c) phytomass estimations for meadows, peat bogs and other non-forest areas; d) reserves of C soil for stands of dominant tree species and non-forest lands. Fig. 3. Distribution of areas and C phytomass in stands of main forest-forming species (logarithmic scale).