Monthly Archives: September 2022

2022 has been a hot one. But the good news is, autumn is nearly here and soon the air will be crisp, sweaters will take over for t-shirts and your trees’ leaves will start to turn. Which then means your trees’ leaves will also begin to fall.  

Do you have a plan? This “almost there” season is the perfect time to think ahead about what to do with your leaves. Luckily, Denver’s LeafDrop program is here to help, giving Denver residents an easy and free way to take care of their neighborhood and city.    

Here are three easy ways you can turn your leaves into something helpful and keep them out of landfills.  

1. CLAIM YOUR BAGS. Before raking up your leaves, use this coupon to pick up a pack of  free compostable paper bags specifically for leaf collection. Free 5-packs of paper leaf bags are available at participating Denver-area Ace Hardware stores.
2. #COMPOSTINGCOLORS. While you’re raking up leaves, be sure to capture the beauty – and the bounty – of Denver in autumn by snapping a photo of your trees, leaves and LeafDrop bags. Learn how to participate in this year’s fall photo contest and use the hashtag #compostingcolors to be entered to win great prizes.
3. DROP IT LIKE IT’S HOT. Keep your raked leaves out of the landfill and compost them for free through Denver’s LeafDrop program. Weekday sites will open to Denver residents Oct. 10. Weekend drop-off sites will open Nov. 4. Remember, when dropping off your raked leaves, if you’re not using these compostable bags, use paper bags – they can be composted along with the leaves!

Try as we might to keep them well and reaching for the sky, sometimes we simply have no choice but to say goodbye to our strong, shady friends. Simply put, trees don’t live forever. And tree removal – while sad to see – is an expected part of the natural lifecycle. The “whys” of tree removal can vary greatly, but there are some rules that stand firm. One thing you’ll hear our foresters say often is “right tree, right place”. This simple reminder also serves as a starting point for the list of reasons a tree might need to be removed. Here are the top five reasons:  

1. Right tree, wrong place.

This one breaks many hearts because, well, it didn’t have to end this way. Planting a good tree in a bad spot generally stems from a lack of understanding or planning on the part of the OP, or original planter. Reasons here can range from HOA regulations that don’t allow planting in certain areas, to some city regulations that don’t allow certain types of trees to be planted under overhead power lines or in certain rights-of-way. The best way to avoid this is to research in advance what’s allowed and where. For example, you should never plant a tree within 20 feet of a stop sign, 10 feet from a fire hydrant or five feet from water meters. And dial 8-1-1, it’s required prior to planting. 

2. Wrong tree, right place.  

Even if you have the perfect location for a tree that meets all the requirements outlined above, there are still some trees that aren’t permitted due to structural issues, overplanting or threats of invading insects. The most common trees planted without permits are silver maple, autumn blaze maple, aspen, cottonwood, evergreens and of course the ash tree, which we know is at the greatest risk for invasion by the emerald ash borer.  

3. Wrong tree, wrong place.   

This is when everything’s, well, wrong. A small spruce tree planted along the street near the corner may not be a concern now, but as the tree grows it’s likely to create a visibility obstruction for drivers and pedestrians. It may also shade the sidewalk and/or street, delaying the melting of snow and ice, which may create dangerous conditions for the public utilizing the public right-of-way. In this case, it’s best to remove the tree while it’s small and before it becomes a safety concern.  

4. Diseased or dead.  

Health and safety of a tree isn’t always apparent to the naked eye. What may look lush and lively at first glance, might turn out to be hollow or otherwise sick, leaving passers-by, property and neighboring trees at risk. Learn how to tell if your young tree is diseased, dead or just dormant. For larger trees it’s probably best to contact a certified arborist to do a health evaluation. 

5. Someone didn’t tree-t ‘em right.…and you thought we didn’t have any tree puns left! 

We already know it – prevention is the best medicine. Infestations may spread to neighboring trees so removal may be necessary to prevent an infestation from impacting adjacent trees. If you currently have the right tree in the right place, we can’t stress enough that you should do whatever you can to keep it well for a long healthy life. That includes regular pruning and care and working with a professional arborist when needed.  

The primary job of Denver’s Office of the City Forester is to attempt to preserve every tree we can, while also following these rules. If you see us removing a tree, it’s generally for one of the above reasons.  If you think a tree is being wrongly removed, let us know by contacting our office at 720-913-0651. 

Hey, we get it – it’s easy to think “the more the merrier” when it comes to trees. But planting any tree in the public right-of-way (areas between the curb and sidewalk or next to the street), isn’t always good for the future of our urban canopy.  

In fact, some trees can be problematic there. The silver maple is one of those trees. As they mature, these trees become tricksters because they tend to decay from the inside out. Imagine if you will, a tree that’s 30” in diameter, looks great – with lots of leaves – but is hollow inside. Now imagine that tree over the sidewalk or the curb, and the harm it could bring if it were to fall. But the silver maple isn’t the only species facing challenges in Colorado. Read on to learn more about approved street trees, unpermitted street trees and those that fall somewhere in-between.  

Get planting!  

The approved street tree list for Denver’s public rights-of-way includes trees that, when given proper and consistent maintenance, including supplemental irrigation, proper pruning and mulching, will be assets to Denver’s urban canopy because of their ability to thrive in our climate. Trees not included on this list may not be planted in the public right-of-way (as a street tree) without express permission from the Office of the City Forester. Here are a couple tips to help you plant it right:  

• When possible, obtain trees that have been grown from a local seed source. Locally grown trees will be adapted to our area’s highly variable, and often harsh, growing conditions.  
• If locally grown trees cannot be obtained, source from locales that have similar growing conditions to our area (precipitation, soil pH, high/low temperatures, etc.)  
• Review these basic tips about planting a new tree.  
• Email forestry@denvergov.org to get your free tree-planting permit! 

Right-of-way? More like wrong-of-way.

Most of the trees listed below tend to develop structural issues. Others create obstructions in various ways. All of them are not welcome in the right-of-way. Per Denver Forestry Rules and Regulations, the following trees may not be planted in the public right-of-way:  

• Any of the poplar (Populus) species including cottonwoods and aspens  
• Any of the willow (Salix) species  
• Boxelder (Acer negundo)  
• Siberian elm (Ulmus pumila)  
• Multi-stemmed trees  
• Weeping and pendulous trees   
• Evergreens  

Hit pause on these . . . for now.

Other trees – for reasons such as insects, overplanting, invasiveness or structural issues – are currently under a moratorium for planting in the public right-of-way, including:  

• Ash (Fraxinus) species, due to the threat of emerald ash borer (EAB)  
• Walnut (Juglans) species  
• Silver maple (Acer saccharinum)  
• Autumn Blaze / Freeman maple (Acer x freemannii)  
• Sunburst honeylocust (Gleditsia triacanthos inermis ‘Sunburst’)  
• Bradford pear (Pyrus calleryana ‘Bradford’)  
• Mulberry (Morus) species  
• Russian-olive (Elaeagnus angustifolia) 
• Tree-of-heaven (Ailanthus altissima), invasive, structural issues and due to the threat of the spotted lanternfly 

If you see a tree excluded from the above list, it may be permitted on a case-by-case basis. Contact the Office of the City Forester at forestry@denvergov.org or 720-913-0651 for details, site inspections and planting permits. As always, we depend on the eyes and ears of the tree loving community to keep us informed.