In autumn, many residents of North America flock to the woods around Lake Superior, sometimes traveling far from home to enjoy the brilliant spectacle of red, yellow and orange displayed by the changing leaves in the forests. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite captured a different, but also spectacular, view of autumn leaves as it traveled 705 kilometers (438 miles) above the Earth’s surface on October 2, 2011.
North of Lake Superior lies Ontario, Canada, where much of the forests remain deep green. This is the Boreal Shield ecozone, where more than 80% of the land is forested and the predominant species are black spruce, white spruce, jack pine and balsam fir – all coniferous species which stay green year-round. To the south, hardwood trees such as white birch, aspen and poplar, mix into the conifers, and appear from space as patches of light color.
Below the border of Canada, three states surround Lake Superior. From the west, these are Minnesota, Wisconsin and Michigan. The leaves along the North Shore of Lake Superior, located in Minnesota, were at their peak on the day this image was captured. The common deciduous species in these forests are maples, birch, aspen/poplar and oak, with leaf colors that range from brilliant red, to bright orange to glossy yellow.
The broadest bands of color can be seen arching along Michigan’s Upper Peninsula, where color was just reaching peak on October 2. The forests here, too, are filled with maple, birch, aspen, ash and oak, blended among bands of green conifer forests. Where stands of deciduous trees mix with coniferous, the color is a mottled or light green. Where stands of deciduous trees are nearly pure, the colors are distinct and bright. Fall color typically peaks in early October in this region, as leaves gradually lose chlorophyll during the lengthening fall nights. Chlorophyll colors leaves green, so as the concentration of the pigment fades, so too does the leaves' green color. Other pigments—carotenoids (yellow, orange, and brown) and anthocyanins (red and purple)—can then show their colors as the green fades.