North American Fruit Explorers mailing list at ibiblio

["Kevin Bradley" <kbradley@ttlc.net>]

I did a little research on this one because I always wondered this myself, that is why a tree that is cut and left out all winter will dry up and why one that remains intact and alive will not dry up even though the soil is frozen and has no leaves to transpire and pull up moisture from the roots. (by capillary action)

I found a study (If you want the name of the study let me know, its on my favorites menu and I don't feel like getting it right now, so there), that compared severed conifer trees to unsevered ones and learned the following:

 

-roots will not take up water if the soil is below 32 degrees F. This is another reason that snow helps greatly in winter survival, it not only protects against root death from freezing but also allows water transport.

-large trees replenish water supply lost during winter by calling on reserves in sapwood.

-smaller trees rely more on their roots pulling up water from unfrozen pockets of soil and from water stored in roots.

 

Still remaining unanswered is the method these trees use to transport this water, I imagine it is strictly through capillary action just as in summer, the leaves transpiring and pulling up water through the xylem tubes, only I guess its much slower in winter. By Jove Watson I do believe I've answered my own question!

 

Kevin Bradley
2201 Carling Dr #5
Madison, WI 53711