A common winter sight in most cold temperate regions like ours are frost-heaves; areas of water-saturated soil that have been uplifted due to expansion and freezing.
Frost-heaving is generally regarded as an undesireable dynamic, because it evidences a lack of organic material or mulch capable of sheltering the soil (and it's microinhabitants) from freezing.
A good diagram I found at the Washington Post
However, on degraded and compacted sites, frost heaves are really a great opportunity for establishing vegetation which can ultimately protect and nuture soil life.
Also, in the coldest of winters, frost heaving can occur everywhere throughout our forest, regardless of how much humus is present. You can feel the crunch of the frost heaves underfoot, even when walking through dense forest with a large amount of leaf fall.
Since these deep-freeze events are infrequent, I believe that they ulimately benefit the forest. Our heavy clay soils can easily become anaerobic and compacted through the naural process of soil settling. The frost-heaves aerate and mix the A and B layers of the soil, re-invigorating soil organisms by giving them the raw materials they need.
The technique is simple; wait until forst heaves form, and then broadcast seed into the holes. As the soil thaws and soil temps rise to satisfactory levels, the frost heaves will collapse, covering the seeds and providing the needed moist soil contact to initiate germination.
Alfalfa seeded into frost heaves in January 2013, doing well in the height of the hot dry summer.
I have successfully germinated plants from seeds sown into frost heaves on many occasions. Notably, in our North Umbria garden space that has been under intensive restoration for the past 3 years.
This year, I took the process to a much larger scale, and sowed innoculated alfalfa seed into frost heaves over an approximately 20 acre swath of land through our developing "main pasture" system, and through an Oak savannah ecosystem that runs across the southern band of the property.
As spring sets in I will be assesing the success of this endeavor. My hope is that the alfalfa can get established in these relatively isolated but harsh conditions - away from the grazing pressure of the sheep and pigs - and can begin conditioning the soil in areas that are hoped to be developed into a paddock shift system in the distant future.
In other areas of the property, I also seeded deep rooted pioneering plants such as Curly Dock and Common Mullein into areas of compacted clay soil. These were typically along primitive roads where we have yet to lay down a road base of crushed rock.
My hope it that these plants will be able to hold down soil, and work as a force of decompaction. To ensure that the soil remains as open and receptive to water as is possible as we infrequenly use these roads.
More pics of the places I seeded into frost heaves in North Umbria.