When Jack pine seeds germinate, the bearberry provides enough protection from
wind and blowing sand to allow the seedlings to grow large enough to fend for themselves.Entering a grove of jack pines is like moving back to an era of colder climatic conditions. As the Ice Age was closing, most cold-adapted plants gradually retreated northward. Provided the proper growing conditions in the chilly pockets between the dunes closest to the cooling effects of Lake Michigan, an isolated colony of jack pines grows 60 miles further south than any other community of jack pines around the Great Lakes.
Jack pines are so well adapted to the cold that they live further north than any other pine. They are able to grow in the humus-free dunes as well as the nutrient poor tundra because they require only small quantities of nutrients like calcium.
Quick Activity - Grab a needle of the jack pine and follow down to its connection on the branch. Its has a partner and the two needles form a bundle. If you put the two needles together you will see they form as one needle that splits apart. The number of needles in a bundle is an important way to identify a pine. For example, the white pine has five needles per bundle, so remember there is one needle for each letter in the word WHITE. If the students want a closer look, have them pick up needles from the ground to prevent injury to the trees.
The low growing Arctic bearberry is another Northern Forest plant. The bearberry reproduces like the marram grass by sending out runners. They can withstand slow sand burial but do not grow fast enough to survive a rapid pile-up. Growing behind foredunes stabilized by marram grass and cottonwoods, the bearberry forms a special relationship with the jack pines.
When Jack pine seeds germinate, the bearberry provides enough protection from
wind and blowing sand to allow the seedlings to grow large enough to fend for themselves.
Common junipers and red cedar trees (a type of juniper) grow in this community. With single needles instead of bundles and having a berry like fruit instead of cones, it is easy to see the difference between these junipers and the jack pine. Junipers often appear on the slopes of the dunes before the taller pines
Quick Activity - Again, allow the students a quick time to make their observations of sunlight, wind, soil temperature, and soil moisture.
During spring migration, the pines can be alive with songbirds
that stop to rest and feed. During harsh winters further north, Great Horned and Northern
Long-eared owls, three types of finches (Evening Grosbeaks, Pine Siskins, and Crossbills)
all seek food and cover in these evergreens.
Quick Activity - Have students look for crab spider webs in the trees. Roll up a small part of a leave and toss it into the center of the web. The spider will come and check to see if it is an insect and then cut the leave out of the web. Don’t use a large piece or you will damage the web.
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