Wind storms down trees

By Marit Gookin

Staff Writer

Recent wind storms have toppled several trees, drawing local media attention. On Monday, gusts of 50-60 mph saw downed tree limbs and even entire trees. However, these wind speeds may strike some long-time Wyoming residents as noteworthy only because trees that have long withstood similar gusts were unable to stand up to them.

Wyoming is the windiest state in the U.S.; the University of Wyoming’s Climate Atlas states that throughout the state, “there are frequent periods when the wind reaches 30 to 40 mph with gusts of 50 or 60 mph.” Trees in Wyoming often noticeably lean to one side – almost inevitably to the east, as Wyoming winds tend to come from the west – or have fewer branches on the side that is more exposed to the wind. While Riverton and Lander are two of the least windy cities in the state, even trees in Fremont County show evidence of how common strong winds are; if our trees toppled every time there were 50-mph gusts, there would be no trees left in Wyoming.

While it’s possible that the reason some trees have recently toppled is ultimately due to wind, the weather’s impact on trees goes beyond the immediacy of windy days. “Part of the reason why we’re seeing more tree problems this year is because, I think, of that extended winter,” explained UW Extension Office Agriculture and Natural Resources Extension Educator Chance Marshall. Marshall emphasized that he can’t speak to whether the trees being weakened is directly resulting in more damage, but many trees in Fremont County and around the state are undeniably less healthy this summer as a consequence of winter weather. “The big thing is that the long, cold winter we had really weakened the trees,” he commented. “A lot of that really set them up to be … more susceptible.” 

There are several factors involved in the impact of both the cold winter and the damp spring and summer on trees and other plants. First, long periods of freezing temperatures can directly impact plants. Additionally, heavy snows combined with strong winter winds can also result in broken limbs, leaving trees with what Marshall described as “open wounds.” Large amounts of snow on the ground for long periods of time also mean that more sunlight is being reflected up onto trees from below – for the same reason that backcountry skiers and snowmobilers frequently wear sunglasses or goggles to protect their eyes from the light bouncing off of the snow – resulting in the plants being sunburnt. 

“It seemed like also there was a lot of animal damage,” observed Popo Agie Conservation District Conservation Technician Dave Morneau. “From large ruminants … but also voles and rabbits.” While the deer and elk were stripping the parts of trees that were above the snow, small burrowing mammals such as voles were chewing their way through root systems. Jack States, a biologist and owner of a non-commercial apple orchard, noted that winter vole activity directly resulted in the death of several of his apple trees. 

And, now that the snow has melted, the plants are vulnerable to bacteria, fungus and infections – especially because many bacteria and fungi tend to thrive in moist, damp conditions. 

“Most of the time, I’m advising people on dry, hot conditions this time of year,” Marshall continued, but this year, he has received a lot of calls from people concerned about the impact of cooler weather. “With the unusual conditions, keeping an eye on bacteria and mold kind of things will be important … When things heat up, it’s going to grow pretty quickly.” 

The snow wasn’t all bad; Morneau observed that the deep snow may have actually provided a measure of insulation to plants in some cases. “Trees and shrubs that were buried in snow seemed like they did better – for example, my Nanking cherries,” he said. Trees that stuck above the snow were exposed to the winter’s extreme temperatures, while those that were completely covered were somewhat protected.

While giving struggling trees plenty of water and fertilizer is tempting, overwatering can be just as harmful as underwatering, and giving the tree too much fertilizer too quickly can shock it. Marshall encouraged those who are worried about the health of their trees to keep an eye on any open wounds, establish a 10-day watering schedule and introduce fertilizer slowly. He also suggested consulting with an expert. “We do have some good resources in Fremont County as far as tree care goes,” he remarked. There are several local businesses specializing in tree care, and he said that any of them could be a good resource for people who have concerns about their trees. “We’re pretty lucky to have those.” 

For garden plants such as tomatoes, people should be careful to give the plants enough space to have proper ventilation. “With things like blossom end rot … I think we’re going to see a lot of that this year,” he commented. 

He also noted that people can help set their plants up to do well through the next winter by continuing to water them into the fall, even after the first frost. “Before that ground is actually frozen, we can still get that water in there,” he observed. Wyoming has a short growing season and early frosts aren’t uncommon, but it isn’t unusual for the weather to warm back up after the first frost. Marshall suggested that people should keep an eye on the weather, and cover their plants at night if it looks like the temperatures are going to dip down.

Many people are concerned about their trees this summer, and rightfully so, as many trees are struggling and have been blown over in this summer’s unusually frequent storms. However, while it may be the Wyoming wind knocking them down, it seems as though it’s the Wyoming winter that set them up.