Comparative spatio-temporal and morphological analysis of urban growth using local climate zones in southern Chile

Southern Chilean cities have experienced rapid urbanisation at the detriment of agricultural use and native forest cover, but data and documentation describing this transformation are limited. This study utilized the Local Climate Zones (LCZ) framework to contribute to traditional land use and land cover change studies by incorporating urban morphology and surface characteristics into a spatio-temporal analysis. The cities of Temuco, Valdivia, and Puerto Montt, which belong to the southern macrozone of Chile, serve as case studies. To evaluate spatio-temporal change based on LCZ, the WUDAPT method was applied by visual interpretation and supervised classification of satellite images and combined with transition analysis and landscape metrics. The results indicate that LCZ related to low-rise and sparse buildings have increased steadily over a 30-year period. From 1988/90–2020, two urban LCZ stand out with high average annual growth rates: LCZ 9-Sparsely built grew on average by 8%, and LCZ 8-Large low rise by 9%. The study reveals significant rural landscape transformation in the analyzed cities, including loss of farmland and ecological areas. Despite this, about 80% of the landscape remains unchanged due to LCZ persistence across all classes. Urban expansion is occurring at the expense of small forest and agricultural zones. These findings support better urban planning by clarifying patterns of urban growth and fragmentation in medium-sized cities.