workshop tree mortality zurich

 

ETH, Zurich, Switserland: 16 September 2015

Organizers: Maxime Cailleret, Jordi Martínez-Vilalta

Attendants: Maxime Cailleret, Lucía DeSoto, Steven Jansen, Jordi Martínez-Vilalta, Elisabeth Robert, Koen Kramer (Skype), Frank Sterck (Skype)

The aim of this workshop was to discuss how the international tree ring-width database already compiled under the STReESS COST action could be used to study the relationship between previous drought responses and future mortality risk. Specifically, we discussed the best ways to analyze and present this data to identify associations between early responses to drought events and future mortality probability, building on the previous work on the same database. Our current database consists of 5003 living trees and 3258 dead trees, belonging to 36 species and sampled (using a paired design) from 199 sites. There are 1618 combinations of site x mortality year. We decided to characterize extreme drought events as situations in which the August, six months SPEI is < -2. For each of these instances we will calculate resistance, recovery and resilience indicators (separately for TRW and BAI) based on Lloret et al. (2012). These indicators will be related to several explanatory variables (including tree size and tree status: living or dead; among other variables characterizing the effected species and the drought event) using mixed-effects linear models. The corresponding manuscript will be submitted to a special issue in Frontiers in Plant Science.