This current book reviews and analyzes forest ecosystems. Chapter One begins with a discussion of radioactivity in forest ecosystems. Chapter Two discusses how litter chemistry has significant effects on soil biogeochemistry and looks into the relationships between litter chemistry, soil chemistry and microbial activity. Chapter Three summarizes information about short- and long-term study of the relationship between soil nematode communities as bioindicators of soil health and different types of disturbance forest soil (fallen trees, fire-damaged) and management (cleared and non-extracted windstorm plot). Chapter Four studies the organization of boreal forests in insular volcanic landscapes of the north-west Pacific. Chapter Five concludes the book with an analysis of the changes of snow moisture balance in logging areas in dark-needles forests of the Yenisei Ridge of Central Siberia.