By Megan Hart, Park Biologist

A walk through the winter woods surrounds you with a sense of quiet and stillness. At this time of year, the forest is cloaked in muted grays, whites and browns as a blanket of thick snow covers the ground. Your walk takes you to the edge of a ravine. Here, the colors shift to include the deep green of hemlock trees, which stand out starkly against the white of the clinging wet snow to their boughs. Standing in the silence of the forest and hearing the wind sigh through the hemlocks, it seems like this magical forest has been torn from the pages of a book. These trees are part of the fabric of what makes Lake Metroparks so special.

The Eastern hemlock (Tsuga canadensis) is the only species of hemlock native to Ohio. These majestic trees are a slow-growing species—it can take an eastern hemlock 20 to 40 years to produce its first cones! That’s right, some of those small chest-high hemlocks you see producing cones could be way older than you think. These sentinels of the Northern and Appalachian forests can live to be more than 800 years old—the oldest on record was 988! Eastern hemlocks can be found from southern Canada to the bottom of the Appalachian Mountains in Georgia and west to the Great Lakes. In Northeast Ohio, Eastern hemlocks can be found growing in ravines, along cliffs edges and on cool northern slopes with moisture, shade and cooler climates.

Eastern hemlocks provide habitat for a unique set of species in Northeast Ohio. Hemlocks help to regulate the microclimate in areas where they grow by keeping the areas cooler in summer and warmer in winter. In the summer, this cooling effect helps to maintain the cold temperatures of the headwater streams in the ravines, which is important habitat for cold-water fish species. Hemlock forests also provide habitat for more than 100 associated species of birds. Some of these species are rare or state listed breeding birds like Blackburnian warbler, magnolia warbler, purple finch, winter wren, dark-eyed junco, black-throated green warbler, and Canada warbler. Hemlock forests provide habitat for these species of birds that tend to have a more northern distribution, which allows them to breed in Northeast Ohio.

Unfortunately, hemlocks are under attack by two non-native pests. The first threat, elongate hemlock scale, is an invasive invertebrate pest that originates in Asia. These scale insects can be found on the underside of hemlock needles and appear to be white or brown flat pill-shaped bumps. The second threat is hemlock woolly adelgid, which resembles small cotton balls stuck to the twigs and branches between the hemlock needles. Both species cannot move as adults but are carried from place to place in their mobile phases on infected tree material, wind and by wildlife. Elongate hemlock scale and hemlock woolly adelgid can kill hemlocks as they feed and weaken the trees over the years. Lake Metroparks has been conducting surveys and a treatment program to save the hemlocks within the parks for several years.

Elongate hemlock scale

Hemlock woolly adelgid

If you would like to experience the magic of a hemlock forest, there are many great options to choose from in Lake Metroparks. There are 17 parks with hemlock forests that are open to the public. Our newest park, Hemlock Ridge Park, has excellent views of Eastern hemlocks and the Grand River. Some other parks for experiencing Eastern hemlocks throughout the year are Penitentiary Glen Reservation, Jordan Creek Park, Indian Point Park, Girdled Road Reservation and Hell Hollow Wilderness Area. On the next snowy day, take a walk and enjoy the majesty of a hemlock forest.