by Cheri Dunning, Executive Director, Three Rivers Land Trust
Three Rivers Land Trust volunteers and I were surprised recently at sudden wilting and then browning of the new growth at the tips of tree branches at the Sanford Community Forest.
While sometimes an insect attack or pathogen can cause similar-looking damage, that is usually limited to one tree or plant species at a time, leaving others unaffected. In this case, we noticed oaks, beech and several other tree species all had very similar looking damage. The outer leaves and up to six inches of twig had died back. Only the new growth was affected, leaving last year’s twigs unaffected.
In the week prior to noticing this damage, we had experienced a hard freeze that saw temperatures fall well below freezing for 4 hours or more. Typically, our native trees can handle a light frost during the spring, but this freeze was harder than most. Orchardists in the area report that many fruit tree flowers were killed by the same cold temps, and we could also see that new growth of some seedlings and smaller plants had died back at the same time. The tender new growth of each tree branch was at the most vulnerable stage when the freeze hit, before the tree had toughened up those newest parts to resist frost. Therefore, the trees lost much of their new growth.
Frost damage on apples at McDougal Orchards
A few weeks after the frost, most plants had recovered, but thanks to those brown leaves and twigs still clinging on, the affected trees continued to look a little sickly in the heaviest-affected areas. People understandably started to wonder if something else was affecting the trees. However, a close look at the twigs of freeze-damaged trees shows that they are rapidly putting out new growth from side buds that had been dormant and therefore protected from the freeze. Although the frost damaged the trees and set them back by a few weeks, almost all trees will have plenty of energy to put out new leaves and continue growing normally. Eventually the brown leaves and dead twigs from the frost will crumble and break away. When this kind of thing happens, the trees need no treatment or special care to recover – just time and warmer weather will do the trick.