Global mountain forests are mostly located in seismic zones and are often disturbed by geological activities such as earthquakes. The earthquake process releases enormous energy. Secondary geological disasters caused by seismic waves can cause physical damage such as stem, branch, or root fracture and distortion of trees, and indirectly affect tree growth by changing the site environment such as soil structure, hydrological conditions, nutritional status, competition intensity, etc., leading to long-term growth release or inhibition of trees. However, it is difficult to separate the coupling effects of environmental changes and climate fluctuations on tree growth, and the spatial pattern and restoration process of the impact of earthquake interference on global mountain forest tree growth are still unclear.

Tree rings have the characteristics of wide spatial distribution, high temporal resolution, and strong continuity, which can record long-term environmental change information. They are a natural carrier for studying the impact of earthquake interference on ecosystems. The sampling points of tree rings in the international tree ring database are often taken for the purpose of studying climate response, mostly from trees at the edge of forests, with weak competition levels, and avoiding obvious damage and distortion. When these tree rings are applied to study earthquake interference, they can more reflect changes in the site environment.

The ecosystem pattern and process team of the Qinghai Tibet Plateau Research Institute of the Chinese Academy of Sciences has explored the impact of earthquakes on tree growth in the seven study areas divided by earthquakes by establishing a global tree ring chronology and the spatio-temporal relationship between earthquake events since 1900, and using the interference information separated from the tree ring width sequence. Research has found that although the impact of earthquakes has a certain degree of randomness and complexity, there are significant differences in climate conditions or terrain characteristics in the large spatial scale where growth increases and decreases after the earthquake. In multiple research areas at mid latitudes, the sample points with increased average tree growth after earthquakes are mainly distributed in areas with less precipitation or unfavorable precipitation storage; In areas with high precipitation, the average annual tree growth after earthquakes generally decreases, indicating that the long-term changes in tree growth after earthquake interference are related to changes in soil moisture at the site. In areas where tree growth increases, the response of tree growth to precipitation during the growing season becomes more sensitive after an earthquake, indicating an increase in precipitation utilization efficiency during the growing season. In addition, after a strong earthquake, the correlation between soil water and precipitation observed by remote sensing weakened, indicating an increase in soil moisture content after the earthquake. This may be due to the occurrence of surface cracks caused by earthquakes, as well as the loosening of tree roots or the contact surface between rocks and soil, which facilitates the formation of macropore flow and increases the infiltration of precipitation during the growing season; In areas with high precipitation, excessive infiltration can lead to soil erosion and nutrient leaching, which is not conducive to tree growth.

This study indicates that strong earthquakes can affect the redistribution of precipitation by altering surface structure, thereby affecting long-term tree growth trends. It reveals the multi layer chain response and spatiotemporal process of the lithosphere atmosphere biosphere. This is a typical case that reflects the processes and functions of the Earth system. At the same time, this study emphasizes the temporal (long-term span) spatial (multi circle connection) tunneling effect of tree rings, which is an important research carrier for breaking the isolation of circles and exploring the complexity of the Earth system.

Recently, relevant research results have been published in Nature Geoscience under the title of Shifts of Forest Resilience After Seismic Discourses in Technically Active Regions. The research work was supported by the National Natural Science Foundation Basic Science Center Program, the second comprehensive scientific expedition on the Tibetan Plateau, and major science and technology projects in the Xizang Autonomous Region.

Paper link：论文链接



Schematic diagram of the mechanism by which soil cracks promote precipitation infiltration and increase tree growth toughness in drier regions after earthquakes