Pear trees in our area have a problem. Cracking, plating, and flaking bark has been reported in many ornamental or flowering pears across the region. What caused this problems and what can you do about it?
The pear problem actually started a whole year ago, it just took awhile for the damage to come to the surface. Those of you in Nebraska might remember last November how we had a severe temperature fluctuation that lead to rapid decline of temperatures to subfreezing levels, aka it got really cold really quick. For some of our trees, pears and willow mostly, the sap wasn’t all the way out of the tree when the temperatures got that cold. When water freezes it expands, and sap does the same thing.
Why did it take until now before the damaged was noticed? Trees put energy into making their buds the year before it needs them. Last fall the trees had already put the energy into making the flower and leaf buds. There was just enough energy in the tree come this spring to have the tree look ‘normal’ as though nothing had happened. Now the energy reserve is depleted in the tree and the tree will start to show signs of stress.
Is there anything to do? Sad to say no, there isn’t anything at this point in time that needs to or could be done for the tree. Leave the wounds open to the environment, do not apply a tar or wound sealing product. It is just going to be a waiting game to see how/if the tree survives the winter. All of the nutrient and water movement happens just behind the bark. If there isn’t any bark there, there isn’t any nutrient or water movement. No movement of these substances and the tree can’t function as it normally would. As a rule of thumb, a tree can seal (not heal) over a wound if it is less than 1/3rd of the trunk. In most instances with the pears that I have seen, the damage to the tree was so extensive that the tree is going to have a hard time overcoming that amount of damage.
There are a couple of options for the damaged trees. If the tree is brittle and the branches break off easily, its not moving any nutrients to that area and it is probably dead. Remove dead branches at any time, especially if there is the chance they could break off in the winter and fall onto something of importance, like the house, car, or people. If the tree does survive the winter, be on the lookout next spring when it puts on leaves. If the leaves are smaller than normal or scattered on the tree, the tree might have a difficult time for long term survival.
Inspect you pear trees for damage. If you need to, prune out the dead or wait until spring to see how the tree survives the winter. Rest easy that it wasn’t anything that you did wrong and it was just Mother Nature in Nebraska at her finest.
Elizabeth Killinger is the Horticulture Extension Educator with Nebraska Extension in Hall County. For more information contact Elizabeth at firstname.lastname@example.org, her blog at https://huskerhort.com/, or HuskerHort on Facebook and Twitter.