Forest Resilience in the Himalayas Inferred From Tree Growth After Earthquake Disturbances

Abstract

AbstractThe Himalayas are one of the most seismically active regions in the world; thus, experiencing frequent catastrophic earthquakes. A growing body of evidence has shown that large earthquakes severely impact on forest ecosystems, particularly in mountain regions. However, little is known about the impact of severe earthquakes on Himalayan forests. Herein, we analyzed tree radial growth patterns following major earthquakes that occurred in 1833, 1905, 1916, 1934, and 1936 in the Himalayas. Based on 46 tree‐ring sites, 77%, 64%, 73%, 72%, and 77% of total analyzed trees showed responses to these seismic events, respectively. On average, 72% of responsive trees undergo growth suppressions following the earthquake events. Superposed epoch analysis showed a strong growth decline 1–5 years after the earthquake. A negative relationship was found between the percentage of responsive trees and the distance of the tree‐ring site from the earthquake's epicenter. The mean time required for 75% of trees to recover reached 5, 5, 5, 13, and 28 years following the earthquake of 1833, 1905, 1916, 1934, and 1936, respectively. The recovery time after a low growth period showed a negative relationship with the distance to earthquake's epicenter. However, the growth resistance improved with increasing distance from the epicenter. Thus, forests located close to earthquakes' epicenters can serve as reliable archive for the reconstruction of earthquakes' impacts. As the Himalayas are prone to earthquakes, adaptive management strategies are required to minimize the impacts of earthquakes on the mountain forest ecosystem.