Shifts of Forest Resilience after Seismic Disturbances in Tectonically Active Regions

Forests in tectonically active regions are disturbed by earthquakes. Besides direct injuries to trees, earthquakes also induce stand-wide changes in hydrological conditions, whose effects on long-term forest growth and resilience remain unknown. Here we establish spatio-temporal links between global tree-ring width series and earthquakes after 1900, disentangle seismic signals from climate-induced variations in ring width series, test growth changes using superposed epoch analysis and quantify post-earthquake resilience shifts along environmental gradients in seven regions around the world. We found sites with enhanced resilience locate in relatively dry areas of temperate regions, where the response of tree growth to growing-season precipitation also increased after earthquakes. Our results provide evidence that earthquake-induced soil cracks and fractures increased precipitation infiltration to deeper soil layers and enhanced the use of water and nutrients by trees. In contrast, reduced post-earthquake resilience in regions with abundant precipitation can be explained by increased soil erosion and nutrient leaching. We conclude that seismic disturbances cause decadal-scale shifts in forest resilience under specific environmental conditions, disentangling complex interactions between lithosphere, biosphere and atmosphere. These findings can contribute to a better understanding of how the Earth system functions. Earthquakes can cause decadal-scale shifts in forest growth resilience by increasing the infiltration of precipitation through earthquake-induced soil cracks, according to global analyses of tree-ring width and historic earthquake data.