Wind Chill

[tbear]

Even on nice sunny days when the wind blows the sap doesn't run well, my understanding is it's because of the chilling factor of wind on the trees. Does it work the other way also? If it's 33°F and has a "feels like" temp of 22°F does that count as below freezing temperature? Just curious, Ted

[DrTimPerkins]

No, wind chill is a term meant to explain how cold it feels for humans (or animals in general). The temperature is not actually that cold, but your nervous system tells you it is colder because of the wind and removal of heat from your body.

Objects like trees (or rocks) don't experience windchill. If it is 30 degrees and windy (and enough time has passed for the object to stabilize) and there is no sun, then the object is 30 degrees, not something lower.

Now what can happen is that heat can be added to the object by the sun, or heat can be taken away faster by the wind (which decreases the boundary layer resistance), but cooling won't drop the temperature of the object below that of the air.

[tbear]

Thanks Dr. Tim. Wind is a one way street, got it. Ted

[3% Solution]

My dad would tell me the old guys would say ( back in the 1930's) ....
Wind from the North sap flows forth
Wind from the East sap flows the least
Wind from the West sap flows the best
Wind from the South sap has a drought
Dos that hold true Dr. Tim???

[DrTimPerkins]

I have an hour-long presentation on biological and environmental factors that affect sap flow and sugar yield which includes that poem. Answer is -- sometimes.

[Ontario Ian]

Answer is -- sometimes.[/QUOTE]

Lol.