This group contains trees which may be used with a great deal of certainty that they will thrive under city conditions of congestion and dusty atmosphere. Wherever possible, these trees, especially evergreens, should be thoroughly sprayed at frequent intervals to wash a considerable portion of the dust from the surface of the leaves.

Abies concolor White Fir

Aesculus hippocastanum Common Horse-chestnut

Ailanthus glandulosa Tree of Heaven

Celtis occidentalis (North only) Nettle Tree

Cercis canadensis Red-bud

Crataegus (in variety) Thorn

Fraxinus (in variety) Ash Tree

Ginkgo biloba Maidenhair Tree

Juniperus virginiana

Red Cedar Picea pungens

Colorado Spruce

Pinus montana mughus Dwarf Mountain Pine

Pinus sylvestris Scotch Pine

Platanus orientalis Oriental Plane

Quercus palustris " Pin Oak

Robinia pseudacacia Black Locust

Salix (in variety)

Willow Sophora japonica

Japanese Pagoda Tree Tilia europaea

European Linden Tilia tomentosa

Silver Linden

Ulmus campesiris English Elm