Report of St. Petersburg Team O.G. Chertov, M.A. Nadporozhskaya E.V. Abakumov Biological Research Institute St. Petersburg State University 2005 INTAS SILVICS

Introduction n A close cooperation with the Pushchino and Fraunhofer teams n Development of a theoretical background for the SOM model n Incorporation of a new experimental data into the models n Formulation a new version of ROMUL model n Test the models for different spatial scales

The laboratory experiments § Impact of biochemical parameters of plant debris on the rate of their decomposition § Impact of the disposition of decomposing matter (pure or in mixture with different soil material) to specify difference of above-ground and below-ground litter decomposition and patterns of decomposition in organic layers § Specification of nitrogen mineralisation in dependence on SOM and soil properties

The field works include: Experiments on decomposition of forest litter fall of different quality in the forest A study of SOM accumulation in a process of primary soil formation

Theoretical analysis of the decomposition process

Model of SOM and N dynamics ROMUL n The model is based on a classical concept of humus type (Humusform) n Experimental base for the model compilation is published and authors data on organic debris decomposition in controlled conditions n The rate of litter and SOM humification and mineralisation is dependent on quality of litter, soil temperature and moisture, and some soil physical and chemical parameters n There is a specification of rate variables for above and below ground litter cohorts n The model calculates the dynamics of organic matter and nitrogen during the decomposition with gross CO 2 and available N evaluation n The model was evaluated against the long-term experimental data n The model is in use as a soil compartment in three forest ecosystem models

Flow chart of ROMUL model

Elaboration of a new ROMUL version n A large set of experimental data for SOM decomposition allows for a revision of ROMUL model n The kinetic coefficients of litter and SOM mineralisation were re-calculated using Bleasdale function and a special program (A.S. Komarov and M.A. Nadporozhskaya) n This allowed to specify the mineralisation rate in two sub horizons of forest floor (F and H) and a peat n A structure and test program of a new version of ROMUL model was compiled and preliminary tested

Calculation of kinetic coefficients of organic debris mineralisation and humification Stage of fast decomposition reflects a mineralisation of fresh organic debris Stage of slow decomposition represents a mineralisation of humified organic debris - not the material with increased concentration of lignin only The function of Bleasdale was used for approximation of experimental curves: y = (a + bt) - 1/c or y = (a + bt) 1/c

Flow chart of a new version of ROMUL model

The use of forest ecosystem model EFIMOD for research and practical implementation at forest stand, local and regional levels n Recently, the idea on the necessity to have a cascade of forest ecosystem models with a different spatial resolution was dominated in the terrestrial ecosystem modelling n Now there are technical opportunities allowing for a use of one basic model type at any spatial levels without the loss of information obtained at the lower levels n Some results of and prospects for the implementation of one basic model type to cover different spatial scales in forest ecosystem modelling were investigated

Methods and Material n Standard EFIMOD simulations of a single stand growth and soil changes were performed for the model use at different scales: n Individual tree growth n Stand level: effects of environmental changes; thinning regimes n Local (landscape) level: silvicultural regimes in forest enterprise (case studies) n Regional level: soil carbon dynamics for a large forest area

Individual tree growth Trajectories of individual tree growth on 25-m transect in a modelled Norway spruce stand Map of individual trees disposition on the modelled plot

Hierarchy of spatial scales for the application of a stand level model Stand level: Parameters of individual trees growth Stand/soil parameters in detail No generalised parameters for forest area Local/landscape level: Optionally parameters of individual tree growth Stand/soil parameters in details Generalised parameters of any format for forest area Regional level: No parameters of individual tree growth Optionally stand/soil parameters in full details Generalised parameters of any format for forest area

The results of EFIMOD runs at different scales shows that n The application of one basic stand-level forest model for different spatial scales has positive prospects for its further development At local and regional levels, this approach was used by Chumachenko et al. (2003: ForRus), Ho et al. (1999: LANDIS), Garman (2004), Kurz & Apps (1999: CBM-CFS2) and Nabuurs et al. (2003: EFISCEN) n The approach can be an additional methodological option that will be more effective for the practical implementation of the forest modelling for the realisation of the concept of Sustainable Forest Management

Case study I and II: Application of the EFIMOD-Pro for the analysis of carbon balance at different silvicultural regimes in forests of Central European Russia

Collaboration with Projects Teams n Close co-operation with Pushchino and Fraunhofer teams n Participation in the Case Study Participation in the interpretation and presentation of the results of geovisualisation and Exploratory Spatial Data Analysis (ESDA) for Case Study

Links to other projects n EU INTAS Project Podzol n St. Petersburg State University Project Changes of Soils and Soil Cover under Anthropogenic Factors n Russian Federal Science and Technology Program Global Climate Changes and Carbon Cycle, part 14 Soil as a source of greenhouse gases

Publications for the period International journals Published4 Submitted 3 Proceedings and national journals Published7 Submitted3 Abstracts to conferences 19

21 presentations at international and national scientific meetings for the period May February 2005 Pushkin, SPB (3) Gent(1) DSS Vienna (3), Uni Hohenheim (1) Trippstadt Forest Station (1) Pushchino (3), Kazan (2), Quebec (1) ForMod Vienna (3) ECEM 04 (2)

Acknowledgements The participants of SPBU team acknowledge colleagues from other teams of the Project, the Administration of the Biological Institute, the Department of Soil Science and Soil Ecology of St. Petersburg State University and the Dokuchaev Soil Museum for their active collaboration and valuable help