Semi-empirical models for assessing biological productivity of Northern Eurasian forests

The Richards–Chapman growth function was used as an analytical basis for a unified system of semi-empirical models describing the dynamics of the main biometric characteristics of major types of Northern Eurasian forests. The growth function was applied at the stand level using yield tables. The models received satisfactorily describe the diversity of growth patterns for different species and geographical regions of Northern Eurasia. A special type of model of biological productivity (MBP) has been developed combining the above growth models and multi-dimensional regression equations of phytomass (living biomass). The latter have been parametrized for dominant tree species, site indexes and ecological regions based on 3507 sample plots collected in Northern Eurasia's forests. The MBP account for age dynamics of forest ecosystems and simulate dynamics of seven components of phytomass (stem wood over bark, bark, crown wood, foliage, understory, green forest floor, and roots) as well as net primary production. The model system could be used in different ecological applications, in forest inventory and forest management as a semi-empirical reference information on the growth and productivity of Northern Eurasia's forests.