Stocks of organic matter and carbon in the underground phytomass of middle taiga deciduous phytocenoses

We carried out the studies of the underground part of phytomass of different-aged deciduous-coniferous phytocenoses of post-felling origin in the middle taiga on the Komi Republic. Data on the stocks of organic matter and carbon in tree roots less than 20 mm in diameter and underground parts of plants of the grass shrub layer at a depth of 40-55 cm were obtained. It was established that from 3.9 to 9.8 t/ha of organic matter and from 1.5 to 4.6 tC/ha were accumulated in the underground phytomass. It was found that in medium-aged deciduous-coniferous stands the mass of tree roots less than 20 mm in diameter was on average 2 times higher, and that of plants of grass shrub layer is 2 times lower than in birch-spruce young growth. The vertical structure of distribution of underground phytomass and carbon stocks is presented. It was revealed that 87-95 % of the root mass is concentrated in the upper 20-25 cm layer of soil. The distribution of tree root mass by species is shown. The obtained results allow us to assess the participation of fine roots in the pool of mobile organic matter and carbon cycle in general in middle taiga deciduous-coniferous stands of post-felling origin.