Autumnal brilliance arrives

The hillsides in and around Duluth are yellow, with bursts of orange and red, interspersed with the dark green of the pine trees and the duller green that lingers in the leaves of some deciduous trees.

A few trees stand naked, already stripped of their leaves from the wind and rains of recent storms.

There’s no doubt that the change of seasons is upon us. How much of a change … well, that depends on where you are.

According to reports on the Minnesota Department of Natural Resources:

• In Jay Cooke State Park the leaves are starting to turn (they were rated 10 to 25 percent on Monday), and the views from the Swinging Bridge and Oldenburg Point are filling with color. Visit this park outside Carlton and you’ll see lots of yellows – flowers including goldenrod and sunflowers, plus ash and oak trees along with the rusty reds of bracken fern and sumac.

• In Grand Portage State Park, 36 miles north of Grand Marais, the leaves are already 50 to 75 percent turned. The maples inland from Lake Superior have really changed a lot in the past week and about half of them are very close to their peak color, the park report stated earlier this week. Aspen and birch are starting to change as well. Wildflowers currently in bloom include black-eyed Susans, ox-eye daisies and asters.

• At Banning State Park, maples are starting to think about fall by showing off their red and yellow leaves. You will also start seeing the understory turning color, trying to outdo the maples. Fall colors are best seen along the Kettle River. Interior trails remain very wet and soggy .

At the beginning of this week, the DNR reported, between 10 and 50 percent of the leaves had changed color along the North Shore. Peak color in the northern part of the state usually begins soon, however, so don’t delay.

Weather is the most important factor in determining the brilliance of those fall colors. Colors are best when high quality foliage – a product of a warm, moist summer like the one we had this year – is exposed to sunny, cool fall days. Cool we’ve had, sunny not so much.

Of course, there would be no autumn magic without chemistry.

Yellow shows up in the leaves each fall as the smaller amount of daylight triggers the trees to break up the green substance in the leaves: chlorophyll. With the warm season winding down, trees are shutting down production of foods so the chlorophyll is no longer needed. In the absence of the green pigments, leaves turn yellow. When the green goes, the yellow shows up.

The red pigment, anthocynin, needs to be produced by the leaves at this time. Made from excess sugars in leaves, it is seen in fewer trees. Red maple, dogwood, sumac, pin cherry and hazel stand out at this time.

Another very common plant with red leaves is not a tree, but a vine called Virginia creeper. Also known as woodbine, this clinging climber now can be seen all over the Northland. These vines were here all summer but, being green like all the others, they did not attract attention. Bright colors changed all that. The Virginia creeper’s leaves are about six inches long and hold five partially toothed leaflets. (With five leaflets, it is not likely to be confused with the three of poison ivy; that is also red now.) Noticeable among the leaves are purple berries, also of the season.

As with other plants of a scarlet glow, the best colors are in sunlit sites, writes nature writer Larry Weber. A red maple may be crimson in the sun, but yellow in the shade of the woods. The same goes for Virginia creeper.

While one only has to look up in Duluth to enjoy the range of colors, those planning to take a drive or go hike a state or national park to enjoy the autumn display should keep in mind these safety tips from Superior National Forest:

• In addition to visitors enjoying the fall color over the coming weeks, hunters will be out and about on the back roads, so please remember as you are driving to watch out for other traffic.

• Take special care on narrow, hilly, and curving forest routes and remember to use headlights.

• Be prepared for a wide range in temperature during the day.

• Frosty mornings could create slippery patches on roads.

• Don't forget to take along a good map and emergency supplies.