A spruce forest’s secrets revealed

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I recently took my high school ecology students on a spruce forest scavenger hunt. It turned out to be one of my more successful efforts to engage students with nature.

While spruce forests are common in Maine, the list of items to be found must be tailored to the specific forest area and to the season. For example, I knew that our area had a nesting pair of bald eagles, a wetland area and deer tracks.

I waited until we were at the site to show students how to distinguish a spruce from a fir by close examination of the needles – a field guide can help you with this. Also, we had just finished a class on lichens.

Background

This activity deals with characteristics of forests in which red spruce and balsam fir are the predominant tree species, accompanied by a few old paper birch, yellow birch and aspen (popple, or poplar). We were visiting a forest in which many of the spruce trunks were larger than 16 inches in diameter at breast height and long strands of a lichen called “Old Man’s Beard” (mistakenly called “Spanish moss” by some) hung from the branches of both living and dead spruce trees. Forest ecologists use these two characteristics, large spruce trees and long strands of the lichen, as an index of a mature spruce forest.

Red squirrels are an indicator species of Maine spruce forests, relying almost entirely on spruce seed for winter food. They store the cones underground at the base of the tree in a cache called a midden. As they feed on the seeds, they discard the cone scales on the surface of the ground. Over time, the pile of scales and old cones grows to a depth of several inches and a width of several feet. Scattered through the midden are holes made by the squirrels as they buried their treasure.

Scavenger hunt instructions

. Work in teams of two students on a team.

. Try to find as many items on the list as possible.

. Only one team can claim a specific example of each item. In other words, find your own!

. To receive credit, your find must be initialed by one of the teachers (adults).

. Stay on the path as much as possible. If you need to venture off the path, do so carefully so as to minimize disturbance.

. Stay within sight of your teachers and talk softly – a better chance at seeing wildlife.

The list

. A spruce tree greater than 16 inches diameter at breast height (measured with a piece of string).

. A tree (dead or alive) with old man’s beard lichen longer than 6 inches (estimated).

. A spruce tree with bark covered by two different lichens.

. A fir tree at least 15 feet tall (estimated).

. A large boulder covered with both moss and lichens.

. A squirrel’s midden.

. An old mossy stump.

. Peeled bark of paperbark birch (on the ground – don’t take it off a tree).

. Lichens growing in a patch of moss on the ground.

. Deer tracks in the ice or snow.

. A wetland indicator plant species.

. A bald eagle.

. A red squirrel (seen or heard).

Consider offering a prize to the team that finds the most items. I offered extra credit points for each confirmed find. Everybody was a winner.