SEASONAL DEVELOPMENT OF TREE SPECIES IN URBAN AND PERI-URBAN FORESTS IN DROUGHT

Abstract

Our study aimed to analyze the impact of extreme drought on the phenological development of Pinus sylvestris L. and Quercus robur L. forests in Ufa city (Bashkortostan Republic, Russia) and outside it. The study area is located in the northern part of the forest-steppe subzone of the temperate climate zone. The vegetation indices NDVI, GNDVI, and CVI were calculated from cloudless Landsat images for the growing season in the dry year of 2010 and time series of 2008-2017, and they were used to analyze the phenological development of forest vegetation. To plot phenology, we used the Bayesian LSP script which uses Landsat time series data and a Bayesian hierarchical model. Higher temperatures in the city led to the higher pace at the beginning of seasonal development of pine and oak forests. The tendency for the seasonal development of forests outside the city to delay continued in the dry year. At the same time, in the dry year in pine forests both in the city and outside the city the delay of phenological development began earlier than in oak forests. Pine forests respond to a long period of water scarcity more noticeably than oak forests, which is substantially due to the features of root systems of Quercus robur that allow them to use deeper moisture reserves.