Progresses in dendrochronology of shrubs
灌木年轮学研究进展

In general, shrubs can grow above or beyond the alpine and high-latitude tree lines, arid and semi-arid areas. They provide a unique opportunity to extend the traditional tree-ring network into high-elevation, high-latitude, as well as arid and semi-arid environments. Despite of their great potentials, around 30 shrub species, to date, have been applied in dendrochronological studies. This paper briefly summarized the major progresses of shrub dendrochronology in high latitudes, semi-arid and arid areas and high altitudes in the past decades. They can be included the following four parts: (1) to detect dendrochronological potentials of shrub species; (2) to identify major environmental factors in controlling their growth, and to reconstruct the past climate change by the annual ring width and isotope of shrub species; (3) to investigate their growth and expansion in response to global warming; (4) to investigate the effects of the warming on the growth and physiology of the shrub species by controlling temperature variations. These studies demonstrated the high dendrochronological potential of shrub species in extending the present tree-ring network, being the most promising research direction in dendrochronology. In addition, most shrub dendrochronology studies focused on the northern circumpolar areas. As the third pole of the world, the Tibetan Plateau has a widespread distribution of alpine shrub species, being an excellent platform in investigating the responses of alpine shrub growth to extreme environments. Meanwhile, shrub species on the Tibetan Plateau provide a unique chance to extend the present tree-ring network beyond the survival limit of forests which are confined to the surrounding areas of the Tibetan plateau. However, dendrochronology of alpine shrub species on the Tibetan Plateau did not get enough attention in the last decades. How can the alpine shrubs adapt to extreme environments? What will happen for their growth and spatial distribution in response to global warming on the Tibetan plateau? These questions deserve further studies in the future.