A Neighbourhood Built Around Its Original Street Trees
Most of the houses in Riverdale went up between the 1870s and the 1930s, packed into rows of Victorian and Edwardian semis on lots that were tight even for their era - Simpson Avenue's "Six Sisters" are among the oldest survivors. The silver and Norway maples along these same blocks are frequently just as old, and a hundred years underground means their roots have grown into, around, and sometimes straight through the sidewalks, foundations and pipes nobody mapped when they went in.
Old trees plus old infrastructure plus lot lines close enough to touch is a combination that rewards a crew who plans before it cuts, rather than one improvising once it's already on site.
Streets Backing Onto The Don Valley Play By A Different Rulebook
Follow Riverdale west and the land drops off toward the Don River and Riverdale Park, and a number of the backyards along that edge sit inside the boundary Toronto protects under its Ravine and Natural Feature Protection bylaw. Injure a tree there, disturb the grade, or move soil around without a permit, and the fines climb into six figures fast - dead and clearly hazardous trees are the only exception.
So before a ravine-edge job gets quoted, the boundary gets checked first. If a permit applies, we're the ones filing it.