For a moment, think about those unseasonably warm January days when you can swear you smell Spring. The air has a heavy, moist snow-melt fragrance. The sun is low in the sky, casting long shadows, and warming dark colored objects…like tree trunks.
The fluids in the trunks of your fruit trees start to thaw, particularly on their south sides, and may even move about from cell to cell. “This feels good” your trees say. Then the sun sets, and the temperature drops precipitously. Tree juices freeze, expand, and the cells walls crack. Ouch. The result is badly wounded tree trunks. That’s Sunscald.
It’s sometimes called “Southwest Disease” because the damage frequently occurs on the south or southwest sides of the tree trunk. There, the direct rays of the sun have been known to heat the bark tissue to over 120 degrees Fahrenheit. And when there’s snow on the ground, the reflection of the sun can make the matter even worse. When the sun drops below the horizon, the cells quickly drop their temperatures, and die.
There’s no easy cure, but with the right material, it’s easy to prevent. Here’s one Heirloom Orchardist’s suggestion, taken from J.J. Thomas’s Rural Affairs (Vol. VI) of 1872:
“Protecting the Trunks of Fruit Trees
Orchardists are familiar with the disease that affects the bark on the bare trunks of fruit trees, particularly at the south and west, where there is so much hot sun at mid-day. The Northwestern Farmer states that a fruit-grower has for several years protected his trees against the hot sun by adjusting a board to shield them from the two o'clock rays, with entire success - adding that since he has tried it, he has lost no more trees, the bark on that side remaining as smooth and as soft as on any other part of the tree."
Today, we have a much easier (and cheaper) method to protect our fruit trees from sunscald: Tree Wrap (left). It’s easy to apply in the fall, is removable in the spring, and can be used year after year. The white color reflects the warming sun rays away from the tree. I recommend this stuff. Plan your preparation now, and wrap your trees before winter sets in.You may also consider a Tree Guard. This will provide some added protection from damage caused by deer, beaver, or mechanical devices.
Another problem that’s easily avoided before winter sets in, is the damage caused by hungry mice and voles. These little guys will eat the bark right off the base of your tree trunk, often girdling it. Many amateur Orchardists don’t even find the damage until winter is over. Then it’s time to plant a new tree, or to quickly learn how to set bridge grafts….not easy.
But prevention is easy. The first step is to remove all vegetation in a radius of about four feet around the base of your tree trunk. This is particularly good for control of voles. They love the cover provided by loose vegetation. Then, install a solid barrier. Again, I provide a comment from J.J. Thomas’s Rural Affairs of 1872 (but I don’t really prescribe his advice):
"Mice Repellers: Generally, a smooth, compact mound of mellow earth, free from grass, and made a foot high, late in autumn, is best. But sometimes a roll of sheet-iron or sheet tin is most convenient. Sheet tin is best, and will rust less than iron, unless the latter is well coated with gas tar. Roofing tin, fourteen by twenty inches, will make to each sheet four protectors, seven inches high and three inches in diameter, costing about five cents each. They last many years. They may be applied after some snow has fallen, with a little pressure and turning about."
Of course you could use roofing “tin” today. You’ll find it at any home center (today it's made of aluminium, or zinc coated copper...not too economical). But it's a lot easier, and more effective if you used pre-made Mouse Guards, manufactured for the purpose.
What's that saying? Oh, yeah...A little prevention today goes a long way.