MINIMIZING ORCHARD DAMAGE CAUSED BY ICE STORMS
February 9, 1998
by Dwight Bradley
The recent ice storm that devastated parts of Quebec and New England was the worst in living memory. Ice storms in that part of the world are fairly common between October and April when the all above a warm front is above freezing, and the air below it is below freezing. What made this particular storm so bad was that the rain was heavy and lasted for many days, eventually building up as much as 1-2” of ice on trees. Evidently, a fairly narrow range of elevations was affected; ambient temperatures were above freezing at the highest and lowest elevations, but the middle elevations were below freezing so ice coated everything.
In large parts of northern New England, virtually every mature hardwood tree was either damaged or killed, newspaper account showed a 100-year-old maple sugar orchard which consisted of 15,000 trees, reduced to a stand of toothpicks surrounded by tangled branches. I have not yet heard any detailed reports on damage to apple orchards, but pictures I’ve seen of various fifty-year-old apple trees look pretty sorry.
All this has prompted me to wonder what I would do about it if the ice storm of the century were to strike my 80-tree apple orchard in Peters Creek, In other words, what would I do if I looked out at 5 AM and to see all the work I’ve put into the past six years threatened. I would be interested in getting your ideas. Here are mine.
- Hot-water sprays. Using an adapter that screws into the tap of a kitchen sink, it would be fairly easy to set up a lawn sprinkler in the orchard that would spray hot tap water onto ice-coated trees in the orchard. Or, a person might just put an adjustable spray nozzle on the hose and melt the ice off each each tree one by one. I can imagine needing to monitor the situation pretty closely, so as to not keep blasting a tree with hot water after its ice falls off. Question: exactly how hot would each drop of water still be when it landed?
- Chemical sprays. I have a five gallon, hand-held spray rig that I use for foliar feeding. There are lots of things besides hot water that would melt ice, but I would be reluctant to apply anything like windshield de-icer, for fear of causing long-term damage. However, various salts might work, dissolved in a five-gallon pail of hot tap water. I suspect that the best salt to use would be a soluble fertilizer such as potassium nitrate, containing as it does, two of the three components of N-P-K. Road salt is cheap and available, but would be bad for soil and vegetation alike, a well-known side-effect of road salting in the Lower 48.
- Other short-term measures. Space heaters? Smudgepots? Small bonfires? Shaking off the ice by hand? Propping up loaded branches?
- Long-term measures: Maintain strong crotch angles on scaffold branches. Defoliate your trees as soon as the growing season ends (by hand if by no other method).