20th century carbon budget of Canadian forests

Abstract

Our analysis of the carbon budget of Canada's forests (1920-1989) indicates that these forest ecosystems have been a C sink approximately 0.2 Gt C yr-1. We attribute our observed C sink to a shift in the forest age-class structure towards a greater average forest age. Forest disturbances, which largely determine Canadian forest dynamics on a time scale of decades, appear to have been less frequent in the period 1920-1970 than in previous decades. They have, however, increased greatly in recent years (1970-1989) and have contributed to a decrease in the C sink. -Authors