Abstract: Disturbance is one of the driving forces of forest community succession, and of significance in forest ecosystems. The impact extent of disturbances on forest ecosystems was mostly depended on the frequency, intensity, and spatial scale of the disturbances, and, excessive and frequent disturbances may lead to the destruction of forest ecosystems. The response of forest ecosystems to disturbances represents in many aspects, and the internal relationships among these aspects are quite complicated. Therefore, it is difficult to define the response of forest ecosystems to the disturbances from one or several phenomena in a forest ecosystem. Aiming to correctly evaluate the response extent of existing forest ecosystems to the disturbances, the authors considered that the response extent of forests to disturbances (REFD) could be related to the change degrees of forest ecosystem structure and function under the existence of disturbance, which only reflect the extent of the differences between existing forests and objective forests (zonal climax vegetation or original forest vegetation) after disturbances, but not the types of intensity and property of the disturbances. The concept and connotation of REFD were defined and explored, and the evaluation principles and methods of REFD were also summarized.

Key words: Straw, Nitrogen, Mineralization and immobilization, Simulation