Just north of St. Ignace and the bridge over the Straits of Mackinac, the sign for the Mystery Spot looked pretty much as it did the last time I saw it. There seems to be a Mystery Spot just about everywhere. I know there are at least three in California alone. Mystery Spots purport to be the sites of “gravitational anomalies”, where you can witness balls rolling uphill and people standing effortlessly at fantastic angles. My guess is that what you see has more to do with clever engineering and our tendency to accept as real what our senses tell us. I am certain too that in any visit to a Mystery Spot, there’s nothing anomalous in the lightening of the weight of your wallet.

If you’ve driven around the top of Lake Michigan, you may have noticed that the forest crowds the highway; trees dominate the landscape, and the mix of trees is different from farther south. All along the route, we’d seen stands composed of conifers (mainly pines) mixed with common deciduous species. And before the novelty of the drive was long gone, my wife wondered why there are “so many pines up here”. She meant “conifers”, in general, and that characterization is not terribly quantitative, but it’s a good observation.

To be sure, countless things influence what grows where (and with what). On a small scale, you could search for answers in differences in soil, topography, or any number of other variables, but on the grand scale of the Upper Peninsula of Michigan, the quick-and-dirty short answer is the way to go. As political commentator James Carville might say “It’s the climate, stupid”.

The climate of any area is shaped mostly by the air masses that grace it and the physical characteristics those air masses possess. In the central part of North America, three primary air masses dominate: Subtropical, Arctic, and Continental. North Pacific and North Atlantic air only infrequently have an effect. Warm air from the Atlantic Ocean collects moisture as it moves across the Caribbean; this subtropical air then flows up the Mississippi Valley and reaching the middle of the country, it heads east. Arctic air masses that form over the Beaufort Sea are cold and dry. They flow south over Canada and turn east also in the middle latitudes. When these two air masses meet, the cold Arctic air sinks under the warm, moist subtropical air, forcing it to rise and cool and often lose its moisture to precipitation. The third air mass develops in the Great Basin area. Prevailing westerly winds drive it east over the Rocky Mountains, which comb out most of the little moisture it held. This Continental air mass often acts to separate the two contentious air masses. When that happens, dry conditions prevail.

The interplay among these air masses mainly determines the climate in the central part of the continent. One clear feature is a climatic gradient that runs roughly east-west from Minnesota and approximately through the central parts of Wisconsin and Michigan and, east of the Great Lakes, through Pennsylvania, New York, and the less mountainous parts of New England. South of the gradient, conditions are relatively warmer and drier. To the north, the climate is cooler and moister; the winters are longer and somewhat more severe, and snow usually remains on the ground all winter. Most precipitation in the north falls in summer where it’s more constant than to the south where there are often summer droughts.

This climatic gradient marks the southern boundary of the “North Woods” (the “North Country”, the “Great North Woods”, or the “Laurentian Mixed Forest Province”, whatever), which extends north through parts of the Canadian provinces Ontario, Quebec, and the Maritimes. It is a vast area that was covered by ice during the last glaciation, and its physical features reflect this pedigree in lakes, swampy depressions, outwash plains, and barrens. Elevations are relatively low, a few hundred feet above sea level to a little more than the 2,300 feet of remnant mountain ranges that in their days would have rivaled the Alaska Range but have been worn down by this last glaciation, other past glaciations, and mostly eons of wind and rain and freezing and thawing.

The North Woods lies between the boreal forests of Canada and Alaska and the ancient deciduous broadleaf forests that radiate from the vicinity of the Ozark Mountains in Arkansas and Missouri and in the southeast, the southern Appalachian region. It is transitional between these two forest zones having components of both. Around 15,000 years ago, there were no trees, only the Laurentide Ice Sheet. Then as the glaciation waned, conifers began to colonize the area in successive waves. Boreal species such as tamarack, spruce, and balsam fir arrived about 13,000 years ago. Probably these initially grew in the soil on top of the retreating ice. They were followed by white pine and hemlock, both from the southeast. Toward the end of the conifer migrations, the flowering trees then began arriving . Oaks and elms first appeared around 11,000 years ago, then maples a little later and finally the American beech.

The Upper Peninsula, where we were, has always seemed wild and remote to me. It’s a difficult place to make a living, even in the best of times, as evidenced by the number of stores along our route selling pasties, gas, liquor, and sundries that have closed their doors. In prehistoric times, the populations of native peoples were much greater farther south. Logging, and later mining, brought in lots of men. In the old days, those industries were practiced rapaciously and all but decimated the forest and landscape. When logging reached its predictable conclusion in about 1930, there was nothing left to hold them and the men who worked the forests drifted off. Now logging and mining are conducted on a smaller scale in a more controlled way and fewer workers are needed. Farming has always been an iffy proposition here; summer is sometimes called 3 months of bad sledding. Those who tried farming, maybe castoffs of the logging days, often gave up, and then they too decamped to more favorable climes.

The forests have grown back since the logging days, though not exactly as before. Nearly 300 years ago when the French came here to trap beaver, convert the native peoples, and search for ingots of pure copper, they found the forests mature (late successional) and dominated by conifers, mostly white pine and hemlock. Deciduous species dominate now, in both mature and juvenile forests. Those French would not disagree with my wife’s observation, but they might be surprised at what she called “so many pines”.