Boundary Waters Canoe Area Wilderness

Native Trees
How Do Trees Survive the Deep Freeze?

Step outside on a 35-degree morning, and you may well wonder how anything can stay alive in northern-Minnesota cold without several layers of Polartec and goose down. But nature finds a way. Trees, for example, employ remarkable mechanisms for handling temperatures far below freezing.

The staples of the northern-hardwood and boreal-hardwood transition forests—trees such as sugar and red maples, eastern hemlock, and white pines—depend on supercooling, in which cellular fluids stay liquid down to about 40 degrees F because there are no solid particles inside cells for ice to form around.

The spruces and firs of the boreal forest are even trickier—they allow most of their cellular liquids to flow into the interstices between cells, where they freeze and insulate the living cells like an igloo. Jack pines, quaking aspens, black spruces, and other boreal-forest trees have evolved thusly to be able to handle truly severe cold—temperatures as low as 80 degrees F.


It seems almost impossible, as you look across the horizon, to begin to separate the thousands of plant species native to the Boundary Waters and neighboring Quetico Park. Here are some helpful descriptions of the various plant life you will find in the northwoods wilderness.

White pine: The white pine is a familiar sight. Its cluster of five soft, thin needles gives it a delicate appearance when young. As the pine matures it stands out on the shoreline due to its impressive size. Used during the logging era as main masts for ships, the white pine is now a common sanctuary for bald eagle and osprey nests.

Red pine: Red pines grow to tremendous size also. They can be distinguished from the white pine by their long clusters of two needles (approximately four or more inches in length). The bark of a red pine will also have a reddish cast.

Jack pine: Like the red pine, jack pine also have clusters of two needles. You can distinguish the two from each other by the short length of the jack pine needles (typically fewer than two and a half inches in length) and the gnarly, rough appearance of their limbs and bark.

Spruce: Both black and white spruce inhabit the area. Spruce have individual needles attached directly to the branch. The needles grow around the entire circumference of the branch, and the individual needles are roundish in shape.

Fir: At first sight, the balsam fir looks much the same as the spruce. Several differences do exist, which will make distinguishing between the two possible. The balsam fir grows needles on only two sides of the branch—rather than all the way around as the spruce does. The balsam needles are flat and have a faint white stripe on the underside of the needle.

Tamarack: Tamarack inhabit wet, marshy areas. Tamarack have clusters of very light green needles about one to two inches long randomly dispersed throughout its branches. The tamarack never really fills out and will have a sparse, almost sickly appearance. Many of the northwoods lakes receive their lightly stained color from the acids emitted from the tamarack's roots.

Cedar: A deer's favorite winter meal consists of cedar, an unusual and unique-looking tree. The cedar has flat groupings of scaly leaves or needles. Cedars inhabit low-lying wet areas, especially near rapids and shorelines. The light brown, scruffy-looking bark hides a strong wood excellent for building. The cedar also has a refreshing scent.

Birch: It is a temptation to pull the white peeling bark from a birch tree, but please don't. Removing bark from trees exposes it to bugs, disease, and certain death. Young birch trees have a deep reddish-brown bark.

Aspen: Both the trembling and large-toothed aspen are native to both the Boundary Waters and Quetico. The creamy, light-green bark and "trembling sound" of their rustling leaves will help you to identify them. Aspen grow quickly and reproduce through an underground root system that produces "suckers," or young trees.

Thanks to Canadian Border Outfitters for sharing this information on Boundary Waters.


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