Update on the Ballard Tree-Cutting Scandal...
I called the City of Seattle and was put in contact with some hippies in the department that handles city tree-cutting. I gave them the address of the alleged crime and they told me that the trees were on private property, but, because of their visibility, were also considered "city assets" and permits are required to cut down said assets.
The property owners did obtain permits for cutting down the trees, so their actions were legal. The owners also informed the city that they intend to plant new trees in the now vacant plots.