tree care

Arborists: The Unsung Tree-Care Pros Who Keep Our Trees Growing Strong and Living Long

The weather is slowly warming up, birds are more frequently chirping and the sun’s setting later—which means spring must be approaching in the coming months. This also means it’s time to start preparing for your spring gardening and tree care needs. And no one is better equipped to help get your trees ready for spring than a tree care professional, also known as an arborist.

What is an arborist?

An arborist is a specially trained tree care professional who has expertise on how to plant, care for and maintain trees. In order to perform tree work in Denver, all contractors must be licensed and insured by the city. Licensed arborists help the City of Denver and property owners maintain private and public trees through tree removal, pruning of dead, diseased or damaged branches, and treatment of insects and diseases. This maintenance helps ensure our urban forest remains heathy and resilient and prevents potential damage to our properties, city rights-of-way and utilities.

What does an arborist do?

Think of arborists like a primary care provider for your trees. They can help assess a tree’s condition, provide recommendations based upon the needs of the species and complete the necessary work, ensuring the health of the tree. Services arborists can provide include:

  • Pruning: Arborists can help you determine what kind of pruning your tree needs, including improvement of health, appearance and safety of the tree. This may include removing limbs that interfere with utilities or structures or obstruct streets or sidewalks. While some pruning can be done on your own, if you’re pruning a large branch or anything from your tree that can’t be reached from the ground, be sure to hire a tree care professional.
  • Tree removal: Some trees, like ash trees, are susceptible to an invasive insect called Emerald Ash Borer (EAB) which impacts all ash species and quickly kills untreated trees.  If you need assistance removing a right-of-way ash tree, Denver’s Office of the City Forester can potentially help through the Ash Tree GAP removal and replacement program. Thyronectria Canker is increasingly common on honeylocusts and is easily spread between trees if pruning equipment isn’t properly disinfected between cuts.
  • Emergency tree care: Removing or pruning storm-damaged trees may be necessary after severe weather events to keep trees healthy and to ensure broken or damaged limbs don’t pose a risk to you or the public’s safety.
  • Planting: Arborists can also help with getting a new tree off to a healthy start by assisting with planting and creating a care plan that you can implement with ease. If you’re interested in planting a tree in the public right-of-way adjacent to your Denver property, you can apply for a free tree.

Why should I hire an arborist?

Trees are assets on our properties. They provide natural beauty year-round, summertime shade and a place for our flying friends to rest their wings. They increase the value of our homes, provide numerous environmental benefits and improve our quality of life and mental health. They’re also an investment—meaning they require proper and regular care. When it comes to caring for your tree, arborists are specially trained and equipped to perform the necessary work.

Depending on what’s required, tree work may be dangerous for homeowners to perform themselves. Licensed arborists are insured and specially trained in safety precautions while treating trees and will come to your property prepared with the appropriate equipment and training to keep themselves, the public and your property safe while caring for your trees. Every tree is unique, and each requires a different plan of care.

What should I look for when hiring an arborist?

When looking to hire tree care professionals, you may want to make sure the company has an International Society of Arboriculture (ISA) Certified Arborist on staff. This certification ensures an individual is proficient in the competencies needed for proper tree care. ISA Certified Arborists have knowledge in areas like tree biology, diagnosis, maintenance practices, proper safety procedures and other subject and practical areas within the tree care industry.

Where can I find an arborist in Denver?

Denver’s Office of the City Forester provides a helpful list of tree care professionals in Denver.

Professional, trained arborists know how to properly maintain trees for the safety of the public and the health of the tree. The best way to ensure your tree stays healthy is to hire a professional arborist. Watch this video to learn more about arborists.

Winter Watering Guide: Caring for Newly Planted Trees During the Winter

Why is winter watering vital? 

In the fall and winter, trees drop their leaves and become dormant as they prepare for colder temperatures. However, newly planted trees experience the greatest growth in their root system during this time. Colorado often experiences dry periods during winter (two or more weeks without snow cover), which can leave roots susceptible to drying out, causing tree death or severe root damage. Not watering throughout the winter is the largest contributing factor to the mortality of newly planted trees. It is best to slowly give any newly planted trees 10-15 gallons of water before putting the hose away for the winter and to supplement with 10-15 gallons of water during dry periods and when temperatures are above 40 degrees. Do not water when temperatures are near or below freezing.   

Watering routine: 

  • Before winter: Continue to water your tree(s) until the ground freezes. Slowly (trickle over several hours) give your newly planted tree 10-15 gallons of water. Don’t forget to disconnect your hose so that it doesn’t freeze.  
  • During winter: Water your tree twice a month, with 10-15 gallons of water if the ground isn’t frozen. This is best done when the temperature is around 40 degrees and at mid-day to allow water to soak in before the ground freezes at night. Continue to check the moisture level of the root ball (the main mass of roots directly beneath the trunk), especially during long periods without snow cover.  

  • Following spring and summer: Continue to water the trees(s) once a week with 10-15 gallons of water and more when the weather is dry, windy or we have prolonged periods of drought and sunshine.   

Additional tree care tips for the winter: 

  • 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. Some community recycling programs like Denver Recycles provide wood chips free of charge.  

Proper tree care during the winter months is crucial for tree health and survival. Following these watering and tree care tips can help your trees continue to grow and thrive. For additional information, read more from the Colorado State Forest Service on winter tree watering.