Applying the litter–bag technique for researching plant litter decomposition processes in natural and urbanized biogeocenoses

In the research of decomposition processes in the urban forest biogeocenoses of the Arboretum of the Botanical Garden of Moscow State University, the litter–bag technique was applied. To determine the leading factors of decomposition of the test materials, the study was carried out in various biogeocenoses of the zonal range: from the zone of mixed forest (Moscow region) to the zone of dry steppes (Volgograd region). Standardized samples of wood, cellulose, tea and native forest litters were placed on the soil surface (within or below the forest litter), then collected at different time intervals. For each study site the dynamics of mass loss were estimated, and some zonal and local decomposition patterns related to the decomposition factors were described. It was shown that the leading decomposition factors are specific to the different materials. Thus, the decomposition of wood and cellulose is controlled by temperature and moisture. The decomposition rate of tea in the initial stages depends on climate, but differs in deciduous and coniferous forests. The decomposition rate of native litters is not controlled by climate in the studied range. In the MSU Botanical Garden, the decomposition of wood is slowed to the rates that are typical for zonal forests located 320–440 km to the south. The native litters in coniferous forests of Botanical Garden, on the contrary, decompose faster than in natural biogeocenoses, which is consistent with previous data on litter-fall input and litter reserves. Thus, the specifics of the use of some test materials for decomposition studies in human–influenced biogeocenoses is shown; in addition, it is shown that the wood can be used as a test material.