Aggregated estimation of the basic parameters of biological production andthe carbon budget of Russian terrestrial ecosystems: 1. Stocks of plant organic mass

The data presented were obtained at the first stage (1993-1999) of studies on evaluating the basic parameters of biological production in Russian terr estrial ecosystems in order to provide information for assessing and modeli ng the carbon budget of the entire terrestrial biota of the country. Stocks of phytomass (by fractions), coarse woody debris, and dead roots (undergro und necromass) were calculated by two independent methods, which yielded cl ose results. The total amount of phytomass in Russian terrestrial ecosystem s was estimated at 81 800 Tg (=10(12) g = million t) dry matter, or 39989 T g carbon. Forest ecosystems comprise a greater part (82.1%) of live plant o rganic matter (here and below, comparisons are made with respect to the car bon content); natural grasslands and brushwoods account for 8.8%; the phyto mass of wetlands (bogs and swamps), for 6.6%; and the phytomass of farmland s, for only 2.5%. Aboveground wood contains approximately two-thirds of the plant carbon (63.8%), and green parts contain 9.9%. For all classes of eco systems, the proportion of underground phytomass averages 26.7% of the tota l amount, varying from 22.0% in forests to 57.1% in grasslands and brushwoo ds. The average phytomass density on lands covered with vegetation (1629.9 million hectares in Russia) is 5.02 kg/m(2) dry matter, or 2.45 kg C/m(2). The total amount of carbon in coarse woody debris is 4955 Tg C, and 9180 Tg C are in the underground necromass. In total, the vegetation of Russian te rrestrial ecosystems (without litter) contains 54124 Tg carbon.