Abstract: As one of the key problems in ecology, interaction is presented in two aspects:(1)the action of organisms on their environment,(2)the reaction of environment(including ncighborer organisms)to the original organisms. The ecological field theory introduced by Hsin-I Wu, Sharpe and Walker, is dealing with the integrated quantitative analysis of these interaction processes, in an attempt to reveal their eco-physiological mechanism. The formation background, definition, basic contents and significance of the ecological field theory are described in this paper.

Key words: phenology, remote sensing, net ecosystem carbon exchange, flux tower, growth season, normalized difference vegetation index (NDVI)