Wednesday, November 26, 2014

Mid-November cold injury

Osage, 24 Nov. 2014
   Last week we experienced extremely cold temperatures for mid November. On November 18th, we recorded a low temperature of 6 F (the -14 C). So this week, I decided to check the condition of some of our mature, nut-bearing trees.
    Each photo that accompanies this post shows the bark peeled back on a fruiting shoot (on the left) and a vegetative shoot (on the right). The caption below each photo identifies the cultivar.

Kanza, 24 Nov. 2014
Chetopa, 24 Nov. 2014

Maramec, 24 Nov 2014
    In peeling back the bark of several cultivars, I found a range of cold
injury. Osage, which produced a light crop this year, had a healthy green color inside the bark. Kanza and Chetopa showed signs on internal browning while Maramec was severely injured by the cold.
     In looking at the Kanza shoots you will note that the fruiting shoot appears to have more internal browning than the vegetative shoot.  I noticed this same relationship between fruiting stress and cold injury with Pawnee last year. In contrast, Chetopa shoots seemed to have the same amount of cold injury regardless of shoot type.
    Both Maramec shoots displayed severe internal browning. However, the fruiting shoot appeared to have suffered greater cellular freezing.
    In years past, I have seen cold injured trees break bud normally in spring and set a good crop of nuts. Pawnee trees injured last winter produced a good crop this fall. It will be interesting to watch how cold injury in mid-November impacts flowering and fruiting next spring. I have the feeling that Kanza and Chetopa will overcome the damage they suffered and produce nuts next year. Maramec may be in trouble for 2015.