Experimentation; Frozen Roots are OK!

Frozen Roots are OK.  Dried out roots are not!

 I had been taught that if you let the roots of dug up trees freeze; it would kill the trees.  Garden centres usually give this as important information, as do tree-people.  But I have proved that it doesn't matter if they freeze, just if they dry out.

I had always been suspicious of this concept, in the same way I am sceptical of the 'Big bang Theroy'.  Oh, and the EU.

My scepticism arose from a curiosity; as to why, if this were so; did baby trees not die, when there was a deep, prolonged and penetrating frost, which froze the ground solid, way deeper than their little roots went.  Also many trees have shallow roots, often being exposed above surface level.  How come they weren't being killed off routinely in the cold weather?

One obvious factor to this is that cold weather in the winter is usually 'dry weather'.
If the wind is blowing from the South West then it's usually mild and raining, but if the cold air is blowing from the East, then it is cold and dry.  

I know from bitter experience, that if the roots dry out; the trees usually die, so I always keep them in plastic bags with a few damp leaves, to keep the moisture in.

Many times the whole bags containing baby trees have frozen solid.  Where the individual trees could not be separated or even removed from their bags, as they were all stuck together with the frost.   
The last three winters were bitterly cold, with temperatures getting down to -20-degrees C, but all those trees were fine.  Even the ones that had not been planted for months and were out for repeated heavy frosts.

I have been keeping a purposeful eye on these trees that had been frozen and all were fine, which in my book; proves my theory and now I have no concern when the temperature drops, but I always take very special care never to let the roots dry out.