Abstract: To quickly and accurately diagnose nutrient limitation factors is indispensable for the study of nutrient limitation in forest ecosystem. Nitrogen (N) and phosphorus (P) are the two popular and major limitation nutrients in forest ecosystem. At present, the main diagnosis methods of N and P limitation to tree growth are fertilization experiment, foliar nutrition diagnosis, and root diagnosis. This paper reviewed the research progress on these methods, discussed the development trend of related researches, and emphasized the significances of the interactions between nutrient elements and the eco-physiological adaptability of plants to nutrient deficiency in the diagnosis of nutrient limitation.

Key words: Northeast China transect (NECT), Stipa community, Precipitation, Net primary productivity (NPP)