Tree species known for heavy shade tolerance are the allegheny serviceberry, the pawpaw and the hop-hornbeam. The maidenhair tree, the red maple and the mugo pine are known for being drought resistant trees. Among these trees, the hop-horbeam is both drought and shade tolerant.
Trees that thrive in shade are uncommon, but some tree species can adapt to darker environments. Flower blooming, fruit production and general development are affected by light access, which is necessary for photosynthesis to take place. Plants growing under shade-tolerant trees are severely affected by the shade of those trees, so they should also be shade tolerant.
The allegheny serviceberry thrives in partial shade, but it's sensitive to dryness. It requires good drainage and does best if planted in alkaline to acidic media. The pawpaw is very adaptable and survives in full sun or full shade, but it requires moist soil with good drainage. The hop-hornbean, used in urban areas as a shade tree, grows well under sun and partial shade and grows in a wide variety of soils.
Drought-resistant trees are characterized by having small leaves and root systems capable of using water efficiently. The leaves are also covered in natural protective waxes. Trees native to the soil and climate of the region are better at handling drought conditions.
The maidenhair tree, or Ginkgo Biloba, is both drought and pollution tolerant, but the female tree overproduces fruit, making it not ideal as a street tree. Although known as the swamp maple, the red maple resists drought, but its growth stops. The mugo pine looks like a shrub but is actually a small tree that acts effectively as ground cover.