MANAGING AND ENHANCING URBAN TREE DIVERSITY: A COMPARISON OF SUBURBAN DEVELOPMENT IN TWO CANADIAN CITIES

Abstract

Given the widespread suburbanization of Canadian cities, it is crucial to explore the mechanisms by which subdivision development influences forest composition. This study assessed whether suburban neighbourhoods in two cities with contrasting pre-urbanized landscapes (woodlands and farm fields) exhibited differences in tree diversity losses or gains due to development. Trees were sampled in neighbourhoods representing two development decades and three land types: remnant woodland, streetscapes, and residential properties. Changes in species-selection decisions likely explain diversification in newer streetscapes in both cities. Older residential properties located adjacent to remnant forest stands were dominated by native trees, alluding to species dispersal across green spaces over time and the ecological importance of retaining woodland during development. Instead of simply aiming to maximize biodiversity in suburban areas, practitioners and stewards should acknowledge differences in forest composition based on land use evolution and tenure, and embrace flexibility and adaptation when shaping and managing tree-species diversity.