North American Fruit Explorers mailing list at ibiblio

[hollaus@comcast.net (R F Hollaus)]

From,

https://lists.ibiblio.org/sympa/arc/nafex/2008-February/023145.html
In the Archives Ernest Plutko wrote:

 

>The air temperature now at 6:30 PM in northern Minnesota is +8 F.
>The ground temperature under 15 inches of snow is now +27.3 F.  Quite
>a difference for plant survival.  I have the sending unit of a
>wireless thermometer in a plastic baggie on the ground surface
>covered with 15 inches of snow.  The coldest ground surface I
>monitored was +18.1 F when it was -34 F a few weeks ago.  The weather
>this winter hasn't been really cold and we don't have much snow.  The
>winter temps have been gradually getting higher.  Hard to say if this
>is a long term or short term warming.  Might be just a temporary
>warming.  A blip.  The coldest I have seen it here was -48 F.  I was
>told this is now 3 ft of frost in the ground.  Under the frost level
>the soil is above freezing.  Any moderately hardy plant should be
>able to live under the snow at ground l evel.  Above the snow is a
>rigorous, killing environment.  When it is -40 F you often hear big
>trees boom when their trunks crack.  Last year a big bur oak next to
>our house cracked.  It had 140 growth rings.
>Winter finally got it.

>

>"Ernest Plutko"

 

Ernest,

 

As cold as +18.1 F is to you in Minnesota I would wonder if this
would be enough to kill the apple codling moth?

 

Comparatively speaking I have also been doing readings where it's
colder longer of Fairbanks in the State of Alaska. In my case I used
a mechanical insertion thermometer and I found -1 F at about 2.5"
below the soil underneath at least 20" of snow and this occurring
March 21, 2007 in -25 F ambient conditions. Being curious I also went
to the hills finding soils averaging 6 F more. Whether in the hills
or not this is apparently mild enough to many of the woody fruits not
just apples. There are some plums and even some unconfirmed reports
that I have heard of Siberian-C peach offspring of the type that Jim
Fruth had alluded to recently...
https://lists.ibiblio.org/sympa/arc/nafex/2008-February/023136.html
(although I have to admit they may not have managed to make actual
peaches on them yet.)

 

R.F. Hollaus (in zone-1 for Alaska)