Is 60 degrees in February a good thing?
So here we are on February 16th, 2017 and its something like the 3rd or 4th day at or near 60 degrees in Sioux Falls, South Dakota. Now I’m not crazy, I love that its this nice. It certainly beats a bunch of snow and zero degree weather. But I am concerned that if these trends continue, it could start having rough consequences for our trees.
Now as long as the soil stays frozen and temps go back down for that soil to stay frozen until April, all will likely be well. But if we stay in these above average temperature cycles it could start causing the trees to come out of dormancy earlier than normal and that is when we could run into problems.
The biggest would be a frost or return to ‘normal’ weather which will kill flowers and early leaf development. Especially in those trees that aren’t evolved to handle leafing out early and can’t handle late frosts.
The other concerns would be tied to the longer growing season. Now in some aspects this would be a good thing, but our trees have evolved with a certain length of a growing season and the pests and diseases that go along with it. Milder winters usually mean higher pest populations in the summer. For example, Pine Wilt Disease (caused by a nematode) was never found this far north because of our colder average winter temperatures. But in recent years the disease has progressed north with the milder winters and is now a major threat in Sioux Falls to our non-native pine species such as scotch pine and Austrian pine. The longer season also leaves more room for trees to be effected by drought or other environmental stresses.
So while all of this is speculation and just a concern. I always feel two sides of emotion when we get these warm winter days. And yes, remember it still is WINTER.