how does this canopy cover affect the heat difference?
Because they reduce air temperatures and surface temperatures
Urban heat island
Trees are a necessary feature in combating most of the urban heat island effect because they reduce air temperatures by , and surface temperatures by up to . 
urbanization is the cause of urban heat island a condition that could be described as The modification of land surfaces how does this island affect the animals? For example, ant colonies in urban heat islands have an increased heat tolerance at no cost to cold tolerance, and Grey-headed flying foxes, found in Melbourne, Australia, colonized urban habitats following increase in temperatures there. does it change according to the season? Yes, the urban heat island temperature difference is not only usually larger at night than during the day, but also larger in winter than in summer. how is it associated with greenery? In recent years, researchers have discovered a strong correlation between neighborhood income and tree canopy cover.
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Urban heat island [SEP] Inequality of tree canopy cover
Researchers hypothesized that less-well-off neighborhoods do not have the financial resources to plant and maintain trees. Affluent neighborhoods can afford more trees, on "both public and private property." Part of this is also that wealthier homeowners and communities can afford more land, which can be kept open as green space, whereas poorer ones are often rentals, where landowners try to maximize their profit by putting as much density as possible on their land.