Monday, May 15, 2017

520 Growing Degree Days (B42)

We had some freezing nights last week and the damage has become apparent.

Chinese Chestnut
Carpathian (English) Walnuts were hit particularly hard.
Although some of the Carpathians seemed to miss most of the damage.
Frost damages is funny stuff.  It can be very local.  Colder air puddles up in low places.  Exposure to the sky will increase radiant heat loss.  Even on the same twig, two buds will super-cool to the same degree, one will initiate ice crystals and die while the other will escape death.

That is one of the weaknesses of single-event, cold stress-tests to determine cold hardiness of seedlings.  Luck plays a part.

Black Walnut for comparison.
Catkins on a Sawtooth Oak tree.  Catkins are where the pollen comes from.
Three Sawtooth Oak marching up the left side of the image.  They are brown with catkins, not newly emerging leaves.
I am coughing quite a bit.  Maybe a cold.  Maybe allergies.  Mrs ERJ suspects allergies.

Some random images.

Pears in the orchard.  As you can see the pear trees are fully leafed out.
Apples.  Not quite as fully leafed out as the pears.
Looking across the pasture.  The trees that are fully leafed out, from left-to-right, Norway Spruce, Red Maple, Sugar Maple, Trident Maple.  The trees that are not leafed out are primarily Black Locust and Northern Red Oak.
Autumn Olive blooming, Major GDD Marker
The earliest specimens of Autumn Olive started blooming a couple of days ago.  These are a major marker because it is a common plant (considered an invasive alien), you can smell the flowers from a distance and it is an important honey plant.
This species also fixes Nitrogen so it is useful even if it is not a native.

Common Ground Ivy (aka, Creeping Charlie) as a ground cover beneath a tree.

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