Here's why:

* Climate: Boston experiences four distinct seasons with warm, humid summers and cold, snowy winters. This is a characteristic of the temperate deciduous forest biome.

* Vegetation: While Boston is heavily urbanized, the surrounding areas have a mix of deciduous trees like oak, maple, and beech, which are typical of this biome.

* Wildlife: Although wildlife is limited in the city itself, the surrounding areas support a variety of animals that are commonly found in temperate deciduous forests, such as deer, squirrels, and birds.

While Boston is a city, its climate, historical vegetation, and nearby ecosystems categorize it as being within the temperate deciduous forest biome.