EFIMOD 2—a model of growth and cycling of elements in boreal forest ecosystems

The model EFIMOD 2 was developed for the description of tree (stand) growth and biological turnover of elements in boreal and temperate forest ecosystems. The model has the following features. (i) It is a spatially explicit stand-level simulator for Scots pine ( Pinus sylvestris L.), Norway spruce ( Picea abies L. Karst) and Pendula birch ( Betula pendula L.) on different forest soils growing under different climatic conditions in Europe; each stand consists of individual trees for which growth is modelled depending on the tree’s position within the stand and local light, water and available nutrient conditions. (ii) The model has a tree-based submodel for total biomass distributed between several biomass compartments. (iii) The calculations include natural regeneration as well as ground vegetation dynamics. (iv) The soil submodel (ROMUL) is used to assess organic matter dynamics and nitrogen availability for tree growth as a function of soil temperature, soil moisture content and litter quality. (v) EFIMOD 2 calculates nitrogen cycling and accounts for atmospheric nitrogen deposition, nitrogen fixation and leaching, vegetation uptake, litter fall and nitrogen redistribution within and between trees and soil horizons. (vi) Monte–Carlo simulations are done to simulate the extent of naturally oscillating variability. EFIMOD 2 allows for short-term and long-term simulations of natural and managed forest ecosystem dynamics over a wide range of forest sites, climatic conditions and silvicultural regimes. The model calculates dendrometric parameters for every tree, including undergrowth and seedlings, total growing stock, and pools of coarse woody debris and soil organic matter, with special reference to carbon and nitrogen dynamics. The model is effective for assessing wood productivity and evaluation of forest management regimes to meet criteria and indicators of Sustainable Forest Management. This includes a general evaluation of biodiversity and soil sustainability. The model system allows for the direct use of standard forest inventory data. Output variables include carbon and nitrogen pools in the stand and soil, CO 2 emissions, and tree (stand) growth and yield.