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Tips and Tricks for Pruning Your Trees

By Urban Forestry Operations Assistant Paul Cancik

With spring upon us, many residents are eagerly planning their gardens and starting to spruce up their yards. Pruning helps trees live longer, which allows them to grow taller and contribute to Denver’s urban canopy. With this in mind, Denver’s Office of the City Forester is offering helpful tips for pruning. It’s important to keep in mind that if you cannot safely prune your tree from the ground, it’s best to hire a licensed tree care professional since they use specialized equipment and have the necessary field knowledge. When you prune a tree, you are planning for the future, and with patience, you will ultimately have results that benefit generations to come.

Why should you prune your trees?

  • Pruning helps ensure that your tree develops a strong form/structure and prevents breakage in the future. 
  • Thinning your tree makes the crown (top) healthier by allowing more air and sunlight to pass through it. 
  • Pruning, much like watering, helps give your tree longevity; future generations will be able to enjoy it.
  • Removing deadwood from your tree helps prevent insect infestation.
  • If pruning is neglected, a tree can become susceptible to breakage, making the tree potentially dangerous.

What should you prune from your trees? 

  • Follow the “3 D’s” of pruning: only remove Dead, Damaged and Diseased wood, especially if the tree is not established. You can also prune branches that impact the structural integrity of the tree. 
  • Be deliberate about what you prune from a tree. 
  • It’s important to prune around stop signs and to ensure sidewalks are clear to prevent accidents on or near your property. Stop signs should be clearly visible and sidewalks free of obstructions. The clearance requirements in Denver are 8’ above sidewalks and 13.5’ above streets and alleys.

When should you prune your trees?

  • While you may prune your tree year-round, ideally the best time to prune is late in the dormant season or early spring, before leaves form. This is typically a good time to remove excess or undesired branches because the tree is not putting forth energy to create foliage.
  • Certain trees, including American elm (Dutch elm disease) and fruit trees in the rose family (fire blight) should only be pruned while dormant to reduce the spread of disease.
  • Only prune a young tree two years after it has been planted and just focus on dead, broken, crossing and interfering branches.  

Tips for pruning:

  • Make sure that every pruning cut you make is clean and smooth. The best tool to use for pruning is a pair of sharp bypass hand pruners for one-inch branches because they make smaller cuts that the tree can recover from faster.
  • Colorado has a very short growing season compared to other regions. A shorter growing season means the tree has a shorter period of time to create and store energy, which ultimately affects how quickly a tree can recover from pruning. A young established tree can tolerate removal of 1/3 of its foliage in a growing season. A mature tree should never have more than 25% of its live foliage removed in one growing season. 
  • If you are pruning something off your tree that you can’t reach from the ground, it’s advised that you hire a tree care professional since they use specialized equipment such as an aerial lift truck/bucket truck and they have the needed field knowledge and expertise. In the City of Denver, tree contractors are required to be licensed and insured. A list of Denver’s licensed tree contractors can be found by visiting https://www.denvergov.org/forestry.
  • If you suspect an insect problem, contact a tree care professional to develop the most effective and environmentally conscious solution. 
  • Covering a wound or using wound dressings is not recommended and may be detrimental to tree health.

Want to learn more? Our friends at The Park People offer a community forester program with classes that cover a variety of topics, including pruning and tree planting basics. You can sign up here: https://theparkpeople.org/What-We-Do/Community-Forester-Program

 Happy pruning!

The Smart Ash Explains EAB Treatment Options

Be A Smart Ash has been turning Denver residents into smarter tree owners since 2016. And while emerald ash borer (EAB) hasn’t yet been found in Denver, we know it’s just a matter of time. But even if Denverites know if they have an ash tree in their yard, they still may need more details about treatment options.

While ash tree treatment seems like a straightforward topic, it can be surprisingly complex. In fact, it combines a good bit of chemistry, can depend on how you feel about your tree, involves some budgeting, and the options can be difficult to demonstrate. In short – ash tree treatment is anything but straightforward.

Enter The Smart Ash. Voiced by our very own Denver City Forester Rob Davis, and inspired by the popular PBS Kids show Wild Kratts, The Smart Ash is a character on a quest to defeat EAB and defend the ash trees that make up Denver’s invaluable urban forest. The campaign is designed to be entertaining but informative – especially when it comes to emphasizing safety and the value of working with a tree care professional to treat or remove trees.

So, join The Smart Ash as he breaks down the various ash tree treatment options into a handful of short videos. Whether you’re searching for a specific treatment option or want to peruse the variety that are available, The Smart Ash has you covered.

Tree climbing arborists help raise EAB awareness

DENVER — Arborists from across Colorado gathered in Denver’s Washington Park for the 2017 International Society of Arboriculture’s Rocky Mountain Chapter Tree Climbing Competition. Here, these talented professionals showed off the skills they utilize day-to-day caring for trees around the state.

From the speed climb competition to much more technical climbs, arborists put a mix of athletics, tree knowledge and math skills on display — and 9NEWS was there to capture it all.

Illustrating their true team spirit, this year’s participants all donned Be A Smart Ash competition shirts, helping raise awareness about an issue they combat every day in their field, the emerald ash borer (EAB). Now the most destructive forest pest in U.S. history, EAB has devoured ash trees in more than 25 states and caused billions of dollars in damage.

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‘Tis once again the season for free trees in Denver

DENVER — If you didn’t end up with a free tree from the Denver Digs Trees program, which began accepting wait list applications earlier this month, there’s still good news: You can now apply for a free tree to be planted in your public right-of-way from Denver’s Office of the City Forester!

That’s right. If your property is adjacent to a public right-of-way that fits these parameters, you can apply to receive a tree at no cost to you.

Why are we so interested in giving away trees? Well, we love trees, for one, and we’re always looking for ways to bolster and diversify our urban canopy in Denver. The second big reason has to do with a tiny green pest.

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