There are very few cities and urban planners who have completely understood the need to promote urban forestry (tress along streets) to support walking/biking. In areas with warmer climate, heat, glare and humidity (and combination thereof) is enough to make even the most ardent cyclists leave their bikes at home. In most cities, building metros, widening roads, adding car (even bike) lanes or parking lots and creating pedestrian pathways are considered activities of choice and no tree is allowed to stand in the way of "development". Its frustrating to most long-term residents of cities as they see busy, beautiful neighbourhoods go bald, dusty and hot. Just compare a bike/walk friendly part of a city with a car-necessary part of a city and the difference made by "tree cover" will become evident. Stronger scientific evidence needs to be generated to assess the impact of trees on pedestrian/biker comfort. This time from an infrastructure development perspective because that's where the change needs to come from.