Abstract: As an important indicator reflecting climatic changes, tree-rings have been widely used in the research of chronology, paleoclimatology, and paleoecology. Annual tree rings are considered as a consequence of the cambial activity and cell differentiation which are significantly associated with environmental variables. Under particularly adverse conditions, the cambial division and growth would be limited or inactive, no xylem or incomplete lignification or damaged cells may be produced in parts of the stem, resulting in abnormal structure of tree-rings. The position of the abnormal structure within tree ring is a time marker for their formation during abrupt extreme events. Such structures include false rings, frost rings, missing rings, light rings, radical crack, fire scars, reaction wood, and traumatic resin duct. These abnormal structures provide a promising approach to better understand growth-climate relations and the physiological processes underlying them. Therefore, they can be used as a climate multi proxy to reconstruct the history of past climatic extremes and to predict future forest dynamics in a changing climate. We summarized the knowledge of some of the most prominent abnormal types of tree-rings, their characteristics and possible causes, and discussed the application in some extreme climatic events or natural disturbances, highlighting the potential of analyzing the features of these special tree rings to reconstruct climatic change history.

Key words: daily global solar radiation, percentage of sunshine, meteorological elements, model.