Even though urban trees on Colorado’s Front Range, Eastern Plains and Western Slope are now going dormant, they require care before and during the winter to remain in top health.
“It’s very important to prepare your trees for winter’s cold, arid conditions, and also to continue watering them during drier periods over the next several months,” said Keith Wood, community forestry program manager for the Colorado State Forest Service. He emphasizes that younger trees require the most care. The CSFS offers the following tips to prepare Colorado’s urban trees for winter:
• Wrap the trunk. In Colorado, thin-barked trees like honeylocust, ash, maple and linden are susceptible to sunscald and frost cracks because of the drastic temperature fluctuations in fall and winter. To prevent bark damage, guard the trunks of younger trees up to the first branches using commercial tree wrap. Leave the wrap on until April.
• Mulch the base. Apply 2 to 4 inches of wood chips, bark or other organic mulch near the base of the tree, but not against it, to reduce soil evaporation, improve water absorption and insulate against temperature extremes. Check your community recycling program, as some programs provide wood chips free of charge.
• Recycle leaves. Instead of disposing of fallen leaves, consider layering them around the base of each tree as a natural mulch, or blend them into the yard with a mulching mower to retain nutrients.
• Prune conservatively. Late winter is the best time for pruning most tree species, but it can be done whenever trees are dormant over the winter months. Common reasons for pruning are to remove dead branches and improve form. Always prune at the branch collar – the point where a branch joins a larger one – and don’t remove any branches without good reason.
• Give them a good drink. Slowly water each tree in the area from just outside the trunk to the extent of the longest branches. Water at the rate of 10 gallons per inch of tree diameter.
Wood says urban trees require additional, regular watering over the winter. During extended dry periods (2-3 weeks without snow cover), provide supplemental water per the guidelines above. The best time for winter watering is on warmer days, when snow has melted off and the temperature is above 40 degrees.
For more information about urban tree care, visit the Colorado State Forest Service website at csfs.colostate.edu.