Street trees in Paris are sensitive to spring and autumn precipitation and recent climate changes

Abstract : Determining the main factors causing urban tree decline is becoming essential for sustaining their health and survival. Understanding responses of tree growth to urban environments and climate change throughout tree life span is thus necessary. To explore these questions, a dendrochronological study exploring past climate-tree growth relationships was conducted on street and park silver lindens in Paris, according to different DBH classes used as a proxy of tree age, and using climatic data for the 1970–2013 period. Younger urban silver lindens presented high sensitivity to climate with highest growth rate. In comparison with park trees, street trees had higher sensitivity to climate and lower growth rates. Climatic and pointer years analysis pointed out the importance of drought characterization in order to understand its potential impact on tree annual growth and functioning. Urban silver lindens growth is mainly and strongly correlated with precipitations and especially in autumn and spring. Finally, our study on temporal evolution between climatic factors and growth through 1970–2013 periods showed a stronger stability between growth and precipitation only in October and revealed quick climatic changes since 40 years impacting the relation between tree growth and climate. Our study highlights that an optimized irrigation management, specifically in respect of tree phenology, could contribute to maximizing silver linden functioning and survival in Paris under climate change.