Why different trees grow in different places

Climate and hardiness

The coldest winter temperature and the length of the growing season set the northern limit of many trees. The USDA Plant Hardiness Zone Map divides North America into zones by average lowest winter temperature, and nurseries use it to say where a plant can live. Sugar maple and paper birch tolerate hard cold, while live oak and cabbage palmetto do not.

Water

Moisture shapes the forest as much as temperature. Bald cypress, river birch, silver maple and cottonwood thrive in wet ground. Ponderosa pine and eastern redcedar tolerate drier sites. Bottomlands, slopes and ridges within the same county can have quite different tree communities.

Soil

Soil acidity, depth and drainage matter. Pines often dominate sandy, poor soils. Sugar maple, basswood and white ash prefer rich, moist soils. Bald cypress and tamarack grow where the ground stays wet. Limestone soils favour eastern redcedar and certain oaks and hickories.

Regions of North America

• Boreal forest across Canada and the north: spruce, fir, tamarack, paper birch and aspen.
• Northern hardwoods in the north-east and Great Lakes: sugar maple, beech, yellow birch, hemlock and white pine.
• Eastern deciduous forest: oaks, hickories, tulip tree and many others.
• South-eastern pine and mixed forests: loblolly and longleaf pine, live oak, sweetgum, bald cypress and palmetto.
• Western mountains: ponderosa pine, Douglas-fir, lodgepole pine and subalpine fir.
• Pacific coast: coast redwood, Douglas-fir, western redcedar and bigleaf maple.
• Desert south-west: junipers, pinyon pines, and the California fan palm in oases.

People move trees

Streets and gardens are full of species from other continents, including Norway maple, horse chestnut and Colorado blue spruce. A tree that does not belong to the local landscape may well have been planted. Check whether a species is native to your area in the USDA PLANTS database.

Using place in identification

Use the range of a tree to remove options. If a species is native only to the Gulf coast, it will not be growing wild in Minnesota. The seasons calendar and the common trees list note where each tree is from.