Sleeping In The Cold
Tips To Keep Our Trees Happy In Winter
By Michael Swanson
Denver City Forester
William Carlos Williams once eloquently wrote: “…having prepared their buds against a sure winter, the wise trees stand sleeping in the cold.”
Winter is here, but that doesn’t mean trees are getting enough moisture to sustain them until spring. In fact, trees need water year-round, especially in our arid climate. Here are a few signs that your trees may be in distress and tips for how to help them stay healthy year-round:
• Use 20 gallons of water per week for every inch of diameter of tree (for instance, a 2-inch diameter tree needs 40 gallons of water in a one-week period). A new tree will need focused watering atop the root ball and then throughout the rest of the planting area.
• Apply mulch around the tree, leaving a six-inch gap between the tree trunk and the start of the mulch; mulch should extend by a three-to-four-foot radius from the trunk of the tree or to dripline (whichever comes first).
• Portions of Southern or Southwestern-facing trees are subject to sun scald. Sun scald is the damage that occurs to living cells just underneath the bark of a tree due to the day-and-night fluctuations during Colorado’s winter months. Signs of damage include discolored and/or cracked bark or sunken areas within the bark. This is a serious byproduct of our warm winter days. To avoid this, you can wrap your tree’s trunk using materials such as cloth or tree wrap available at a hardware store. Butcher paper is a great tool as it’s waterproof and removes/absorbs some of the energy that the sun produces.
• Keep an eye out for signs of emerald ash borer (EAB), which has destroyed millions of ash trees in the Midwest, has been discovered in Boulder and recently in Arvada and will inevitably arrive in Denver sometime in the near future. There are an estimated 1.45 million ash trees in the Denver metro area, including 330,000 in the City and County of Denver. That means that one in six Denver trees are ash trees, and they can be found everywhere in the Mile High City – with the majority on residential properties.
• Become familiar with the Be A Smart Ash campaign, which aims to actively educate and enlist the help of Denver residents in the process of identifying, treating and replacing ash trees.
• Check out an interactive tree inventory map and information about ash tree treatment options and resources to find a tree care professional, at this link: beasmartash.org/do-i-have-an-ash-tree/interactive-map/.
Learn more about winter tree care by watching the third episode of Water, Trees, Life, at https://youtu.be/Ff3wqWv6R_I. Let’s help our trees so we can enjoy their healthy urban canopy next year and for years to come.