XIM4 meeting report, Sept. 25-27 2019, Padua (Italy)The hydraulic community has taken a step forward towards non-invasive measurements

The fourth edition of the international xylem meeting was held for the first time outside France. This represents an important step forward for the meeting and attests to the resolutely international dimension of this symposium. The conference was organized by the University of Padua in the green setting of the botanical garden. No less than 140 researchers from more than 21 countries attended these three intense days of seminars and discussions. For logistical reasons, the number of places had been limited by the organizers, which forced us to decline a number of registrations. This tends to prove, if there was any need, that the community of researchers in xylem physiology and plant hydraulic functioning is booming, and that these meetings are becoming an essential biennial event for our discipline. For this edition, no less than a hundred communications were presented, including about fifty plenary talks. It is difficult to summarize all the richness of this work in a few lines, so we propose here to highlight some of the most salient points. A scientific community in tune with its society While we were discussing our scientific work in session, more than 20,000 peaceful demonstrators marched for climate in the streets of Padua. In a manifesto published on social networks and signed by all congresses, we wanted to remind that: "We, as an international community of plant scientists, support climate change mitigation. Our investigations of trees, forests and climate dynamics clearly show that critical ecosystems are being threatened by increasingly frequent extreme climatic events. Large-scale tree mortality across the globe demonstrate the severity of the threat that we are facing and demands actions." Our work on the hydraulic functioning of plants allows us to better understand the response of trees to future climate change, especially to drought events, and their ability to adapt or migrate. We must also take advantage of these scientific meetings to better communicate with the general public, the media and political decision-makers, and to explain what will be the consequences of the ongoing climate change based on scientific evidences. It is our responsibility to alert people of the serious risks that our current lifestyles pose to natural and anthropized ecosystems. We will try not to miss this opportunity during our next meeting