Through the 20th century, US and Canadian urban forests suffered the consequences of low taxonomic diversity. The arrival of invasive urban forests pests and pathogens like Dutch elm disease and emerald ash borer ravaged monoculture urban forests. Yet, many urban foresters maintained that a native-only species palette should be used for street tree planting. This presentation details the results of a geospatial analysis of taxonomic diversity in Canada’s street tree population using the Open Urban Forests repository – the first national-level collection of Canadian urban forest inventories. Using the Royal Botanical Gardens, KEW database, we standardized species names and identified them as native or non-native species. We examined taxonomic diversity and native proportions across cities, comparing city sizes and ecozones, and within cities, comparing downtown and non-downtown areas. Our results demonstrate that warmer climates have more taxonomic diversity yet lower native species proportions. Native species proportions were also higher in downtown areas. We also examine how ash and elm are not always the dominant tree species and genera. Rather, new taxa are climbing the ranks, becoming dominant assemblages of the urban forest.