OUTSIDE: The freeze in the trees

Published 9:40 am Tuesday, May 4, 2021

By Steve Roark

We had a hard freeze recently at a bad time for some trees, with many just putting out those very succulent and tender new leaves.  A number of trees and shrubs got hammered in my yard, totally wiping out all of the leaves, and many forest trees took the same hit. If your trees were impacted too, you may be wondering what all this means in terms of tree health and fruit/nut production.

Apple, pear, and other fruit trees were blooming or were just finishing up when the recent 2-day freeze happened, so some fruit embryos were probably damaged. Temperatures were in the mid-twenties at my place, so some may survive and to produce fruit.  In the forest hard mast production (acorns, hickory nuts and walnuts) may be low this year as well, which will impact many wildlife species such as deer, turkey, and grouse.  Soft mass-producing trees (dogwood berries, blackberries, cherry) bloom later so they are probably okay.

Leaf damage depended on how far along they were.  Those where the leaves were barely unfurling got the worst damage.  Trees typically area able to put out a new flush of leaves, but some will do better than others.  Some trees have what is called determinant growth, which means they are genetically wired to produce a set number of leaves.  Trees with determinate growth include oaks, elms, sassafras, mulberry, hickories, walnuts, ash, and cherry.  Their canopies may look a little sparse this year.  Trees with indeterminate growth will put out new leaves as long as temperature and moisture are adequate and should put out all new leaves and look normal. Trees with indeterminate growth include yellow poplar, sassafras, and dogwood.   Having to put out a second crop of leaves will drain energy reserves and cause some tree stress, and if other stressors like drought occur during the growing season it may do some harm.  So be sure to keep frost damaged trees and shrubs well-watered this year.  Newly planted trees will be particularly vulnerable because they don’t have a well-established root systems and lack energy reserves.  So, water well, but don’t fertilize this year.

As far as other structural damage to the tree, I think it will be minimal.  There may be some small twig dieback if the wood is this year’s growth and was succulent, but I don’t think this will cause much harm.

Steve Roark is the volunteer interpreter for the Cumberland Gap National Historical Park.