Trees of the same kind will become stunted in sections where dry weather persists.
In some parts of the United States forestry experts can tell where they are by the local tree growth.

For example, in the extreme northern districts the spruce and the balsam fir are native.

As one travels farther south these give way to little Jack pine and aspen trees.

Next come the stately forests of white and Norway pine.

Sometimes a few slow-growing hemlock trees appear in the colder sections.