I have observed and seen reports from many locations in northern Utah of fruit and nut trees dying back in the shoot tips. The ends of branches in the tops of trees are dead, while shoots lower on the tree grow normally. Some young trees have been killed outright. What conditions brought about this injury?
In October 2019 and 2020, we experienced precipitous drops in temperatures. Trees can easily survive temperatures in the 20’s when fully acclimated; injury is caused by a lack of time to acclimate to the cold temperatures.
Ice formation damages membranes and, life ceases. As temperatures drop in the autumn, plant cells dehydrate as part of their acclimation process. When insufficient acclimation time is allowed, cells are full of water, and damage ensues. The result we see is die back in the upper parts of trees or death of entire young trees.
What can you do to remedy the situation? The dead branches will not come back to life. Prune off the dead branches just slightly into the living tissue. For large trees, employing an experienced arborist will be required to remove the dead and dangerous branches.
Further, even though we are all underwater restrictions, trees need water to survive. Less frequent deep irrigation is best for trees. Soaker hoses can be a great tool for watering trees. Place the soaker hose in a circle out three to four feet from the base of the tree, and barely open the hose valve. Allow the soaker to run for several hours with just a trickle of water.
Alternatively, a sprinkler could be placed under the tree and turn the hose valve to a low flow to allow the water to soak deeply into the tree root zone.
Hopefully, this fall will provide better conditions for cold acclimation.