A computer model of the solar radiation, soil moisture, and soil thermal regimes in boreal forests

Our current understanding of the ecology of boreal forests indicates that vegetation patterns within the circumpolar boreal forest reflect a complex interrelationship among climate, solar radiation, soil moisture, soil temperature, the forest floor organic layer, forest fires, and insect outbreaks. In this paper, a simulation model was used to explore the environmental subset of this interrelationship, specifically the interactions among solar radiation, soil moisture, soil freezing and thawing, the forest floor organic layer, and forest fires. The model solved for these environmental factors on a monthly time step using easily obtainable soils and climatic data. The algorithms developed in this study successfully reproduced local, seasonal patterns of solar radiation, soil moisture, and depths of freeze and thaw for different topographies at Fairbanks, Alaska. These same algorithms also reproduced regional patterns of the annual solar radiation, soil moisture, and soil thermal regimes in boreal forests of North America, Scandinavia, and the Soviet Union. By calculating these environmental factors on a monthly time step, these algorithms operate at a temporal scale suitable for individual-tree models of forest succession, which can be used to study extent vegetation patterns in boreal forests and the possible ecological consequences of climatic changes.