Will silver fir be under higher risk due to drought? A comment on Walder et al. (2021)

There is large uncertainty on the future of European silver fir (Abies alba) forests and how they will respond to climate warming. Many studies, such as Walder et al. (2021), suggest they will show positive growth trends and a larger distribution area in response to warmer conditions whenever summer drought is not severe and long. This contradicts localized dieback events in continental, drought-prone Mediterranean sites mainly located in the southwestern margin of the current species distribution range. We discuss these disagreements and propose compound climate extremes and elevated atmospheric drought as drivers of dieback in similar marginal silver fir populations.