By 11,4000 to 11,000 years ago the Wisconsinan glacier, the ice sheet, had melted back to the distant horizon in this photo of the Kilkenny Wilderness. The melting glacier created a large lake in the valley between the northern Presidentials and the Kilkenny ridge, right down there where you see US Route 2 in the photo. The lake extended from the right hand side of his photo all the way to the left to where the present towns of Whitefield and Littleton, NH, are located about 35 miles to the west. This lake eventually drained off to the south by way of the Saco and Connecticut River watersheds.
One of the truly striking things about the glacier ablating is the question of the return of the boreal forest to this region, how long it took and what it was made up of in terms of species of plants and trees. Climate (temperature and precipitation), water, cloud cover, and length of daylight and, most important, the amount and quality of the soil and the availability of seed sources, would all play a role in determining the vegetation that followed the glacier.
I like to think that soil building is the principal activity of the combined natural forces on Earth; that all living things, the weather, the sun and moon, are all working in unison to cover the Earth with a rich layer of healthy soil. For instance, when I am in the woods in the fall and the wind is blowing the leaves around I like to think of it is “redistributing the wealth” of soil nutrients by distributing the leaves more equally. I even go so far as to say soil is our only true wealth, but that may be overstating things. And to be realistic the wind doesn’t equally distribute the leaves, either. At any rate, I do think that the large continental glaciers played an enormous roll in creating the soils of the northern hemisphere around the globe. Glaciers, along with plants and animals, over time created some amazing soils. Where I live in the Connecticut River Valley of Massachusetts, the so-called Pioneer Valley, there's a glacial soil here, actually formed under Glacial Lake Hitchcock, that is called, simply, Hadley Loam, a light, sandy loan, that is arguable one of the best soils in the world. When you slide your hand down into it feels alive. It’s great for growing things like corn and onions, etc. It sits comfortably on a thick layer of mixed glacial till with superb (in most places) drainage characteristics. I’ll say more about soils of the White Mountains later. I just want to throw this notion out that glaciers, in moving so much solid “stuff” are key soil builders and when you think of the enormous damage done to New England forest soils by Acid Rain alone, the leaching of key nutrients by the acid, you can think of another ice sheet descending and with it tons and tons of “rock fines”, the ground up, powdered form of essential nutrients, the magnesium rich silicas and the acid neutralizing calcium, as the perfect remedy to reverse the effects of Acid Rain and, hopefully, return the native soils to a less acidic "circumneutral" pH.