The project aims to assess the biotic and abiotic factors regulating fragmentation and mineralization of bark of main boreal tree species as well as to assess the role of presence and quality of bark included in the litter and attached to logs in the boreal forest biodiversity. The project is especially important because of the lack of information about the bark as a component of nutrient cycling and as a substrate and a as a food source for many organisms of different taxonomic groups. Such information is necessary for addressing many basic scientific problems including estimating carbon balance in boreal forests, assessing and forecasting biodiversity, modelling forest dynamics in view of global climatic changes. Practical implication of such information includes utilization of the bark waste, facilitation of its decomposition.
The scientific originality of the project lies in its complexity and novel methodological approach. First time, the mechanisms of fragmentation and mineralization of bark will be characterized using modern methods and molecular techniques as well as mathematical modelling. The project objectives will be fulfilled in the three experiments supplemented by additional research. Two experiments will be established in the “Kivach” reserve. The estimations of bulk density and mass of bark, CO2 emission will be made on the same fallen logs of different tree species, decay stage and time since tree death. The inventories of the organisms, associated with bark using recording (for wood decaying fungi and epixylic species), rearing with trunk emergence traps (for insects) and DNA sequencing (for fungi) will be inventoried on the same logs. The mass loss and carbon emission as well as the species composition of fungal communities will be also estimated for the bark in the logging slash on the clear cut areas. The third experiment aims at estimation of the carbon fluxes from decomposing bark of Norway spruce in piles in vivo and in small samples in vitro. The additional estimations of bark decomposition and characteristics of epixylic successions will be made on the study sites located in primeval and managed forests in all boreal sub- zones.
The main project result is the conceptual model of microsuccession of communities of different organisms, associated with bark. The model includes quantitative characteristics of fragmentation and mineralization of bark of main boreal tree species. First time the effects of biotic and abiotic factors on the fragmentation and mineralization of bark attached to logs and included in litter will be estimated based on the calculations of mass loss and on the measurements of carbon emission. The CO2 fluxes, mass loss, C and N losses in combination with the temperature and moisture measurements will be estimated also from bark piles during 2.5 years of composting. First time the complex estimate of bark decomposition will be made separately for floem and cork in natural and laboratorial conditions at a broad range of temperature and moisture using mathematical modelling. First time the role of bark attached to fallen logs in the diversity, including “hidden” diversity will be described for the saprotrophic and saprophytic organisms. The results will include the identification and characterization of a microbiome, associated with bark in European boreal forests; patterns of microsuccessions of epixylic vegetation on the fallen logs of main boreal tree species and the factors, influencing the rate of these successions and the species composition of epixylic groups on different stages; as well as the estimation of trophic and other relationships between mosses, hepatics, wood decaying fungi and insects associated with bark.