The high elevation forests and north facing slopes in the northern part of Frederick County contain a tree mixture that is much more common in northern states like Michigan, Pennsylvania, New York, or Garrett County, Maryland.  This is because these cooler “micro-climatic” conditions favor trees that are more adapted to northern latitudes.  This is a relatively uncommon forest association in our county.

Cool, damp micro-sites like this area outside of Thurmont harbor tree groupings
that are much more common to the north.

These Northern Hardwood Forests contain trees such as red and white oak, tulip poplar, beech, white ash, shagbark hickory, red and sugar maple, hemlock, cucumber magnolia, yellow birch, basswood, and white pine.   The sub-canopy of these forests contain a fairly unique species mixture some being relatively rare in our county.  Some of the more unique trees and shrubs found in these areas are rhododendron, striped maple, hemlock, sourwood, American hornbeam, and eastern hop hornbeam.  Hemlock used to be a very common component of these transition forests but their numbers have greatly diminished due to an insect know as hemlock wholly adelgid.

A rare grove of hemlock persists next to Catoctin Creek near Middletown.

Frederick County is uniquely situated so that many of the southern and northern tree varieties intermingle in our county.  These small pockets of northern transitional forests form a small representative sample of vast hardwood forests lying to the north.