Research on Trends in Extreme Weather Events and their Effects on Grapevine in Romanian Viticulture

Abstract

The aim of this work was to investigate the frequency and intensity of extreme weather events in various centers from Romania’s viticultural regions: winter frost, extreme temperatures during the growing season and summer droughts. Winter frost damaging the vine is a significant risk to grape production, mainly in the plains and lowlands to the foothills. The frequency of winter frost damaging the vine has increased during the last decades, in the context of climate change. Also, there has been found a significant increase in the number of hot days (Tmax > 30°C) and very hot days (Tmax > 35°C). The evolution of these extreme events was followed in Craiova, Constanta, Bucharest, Timisoara, Cluj-Napoca, Oradea and Iasi, between 1977 and 2015. The long term study (18 years) conducted in the experimental plantation of the University of Agronomic Sciences and Veterinary Medicine Bucharest revealed their influence on vine. During the last two decades, there has been registered a trend of increasing the frequency and intensity of winter frost, damaging vine (Tmin < -20°C), heat waves (number of days with Tmax > 30°C and > 35°C) and droughts that adversely affect viticulture, production and quality of grapes and wine. The highest warming trends were observed for northern viticultural regions (Transylvania and Moldavia) and for the seaside. Although the intensification of heat waves increases sugar accumulation in the berries, they trigger a significant reduction in grape production and in titrable acidity, requiring corrections and resulting in unbalanced wines. Meanwhile, droughts trigger production decrease. To avoid negative effects on vine, it is necessary to take measures, both on a short, medium and long term.