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Monthly Tree Care Tips
Welcome! We're so glad you're here! Our Forestry pages offer information on all aspects of tree care. Beginning in January, this page will feature a new tip every month to help you take the best care of your trees.
If you find you need help with a tree located on your property, we have a list of licensed arborists who are certified with the Town of Berthoud. If you have questions about a tree located on the grassy area between your sidewalk and the street, call us at 970-532-4256 and we will happily come out and look at it for you free of charge.
Basics of Tree Anatomy
**If you have any questions about this topic or about your tree in general, don’t forget you can email the Berthoud Forestry Department at forestry@berthoud.org , or call them with questions at (970)-532-4256 and leave a voicemail. **
We wanted to devote January to teaching readers about some important parts of tree anatomy to pay attention to. With a little knowledge on these parts of the tree, hopefully a lot of the concepts covered throughout these monthly tree tips make more sense.
Tree Cambium
This is the area of the tree trunk that has living cells responsible for tree growth. The cambium is composed of two separate types of cells, ones that move water throughout the tree, and ones that move sap (food) throughout the tree. These living cells are located just underneath the bark of the tree. This layer is also responsible for the outward growth of the trunk.
The reason we point out this important part of tree anatomy is to show that this layer is responsible for moving nutrients throughout the tree. Think of it as a main artery for the tree. Some trees have thicker bark that protect this “main vein” of the tree, but others don’t. The bark or cork is the only layer of protection for these vital “veins” of the tree. This is so important to know so you don’t hit your tree with the edge of your mower, or hit it with a string trimmer. This damage caused by equipment can cut these “veins” and can stop the flow of nutrients up the trunk of the tree. If this damage goes all the way around the outside of the trunk, it can fully cut off the flow of nutrients to the branches above and kill the tree. These cells can heal small amounts, but significant damage usually never fully repairs and that damage is there for the life of the tree.
Branch Collar
The branch collar is an important part of branches to look out for when pruning. This area on the branch appears slightly swollen compared to the branch. This is an area where the branch and trunk cambiums overlap. This area aids in the structural rigidity of the branch but also has the living tissue that will envelop the pruning wound, sealing the wound. If this area is cut into during the pruning cut the wound wood might form inconsistently and not fully close over the wound.
Root Flare
We wanted talk about the root flare of the tree and its importance. When seeds sprout, they quickly differentiate between the roots and the main stem/branches. This area on a tree cannot change or move around. When humans move plants around and replant them elsewhere this area should not be buried in the ground too deep or too high. It can cause stress to the tree, and can potentially kill a tree. This is very important to consider when planting a new tree.
Trees should not look like telephone poles at the ground. This tree was either planted too deep or recent construction raised the grade around the tree.
This is a proper root flare for a tree.
Tree roots
The roots of the tree collect water and nutrients from the soil and move it up into the canopy of the tree. The one thing we wanted to clarify here is misconceptions about roots. The roots of a tree are actually much wider reaching and shallow than you might realize.
The tree on the left is usually an artistic depiction of trees and their roots, when actually most tree root systems look like the tree on the right. Keep this in mind when watering your tree.
Links for extra reading:
Understanding Tree Roots - CSU Extension
Tree Growth and Decay - CSU Extension (This extension fact sheet covers branch collars and tree cambiums in more depth)
Winter Pruning
**If you have any questions about this topic or about your tree in general, don’t forget you can email the Berthoud Forestry Department at forestry@berthoud.org , or call them with questions at (970)-532-4256 and leave a voicemail. **
Winter is one of the best times to prune trees. Not only can you see all of the tree’s branches with all of the leaves gone, but it is also less stressful for the tree to be pruned while dormant. Smaller branches can be pruned off with hand pruners or loppers. For larger branches that might need removal with a saw, consider using the three-cut method to remove the branch to reduce the chance of bark tearing. Proper pruning cuts should heal fine if they were made in the right spot on the branch and are not too large.
When pruning any size tree branch, try your best not to cut into the branch collar.
A branch removed at the right size and in the right place will ideally fully seal over the wound.
In the photo above we can see a branch starting to seal up a wound after a proper pruning cut was made.
Here is another picture of a pruning cut that has fully sealed over a wound. This is the ideal outcome with all pruning cuts.
Considerations-
• Branches smaller than 2 inches in diameter should be able to heal properly after pruning. Frequently as trees get larger, some branches get removed that are bigger than 2 inches in diameter. While not ideal, some of these branches will need to be removed for various reasons.
• Clean cuts are easier for a tree to heal over rather than rips, tears and breaks.
• Be proactive- most trees do not need large pruning projects every year. If you are taking off problem branches while they are small, it is not only ideal for the tree, but also for you.
Links for extra information:
Young Tree Pruning Tips - Pruning Continued
**If you have any questions about this topic or about your tree in general, don’t forget you can email the Berthoud Forestry Department at forestry@berthoud.org , or call them with questions at (970)-532-4256 and leave a voicemail. **
There is so much information about tree pruning, we decided to devote two months worth of tree tips devoted to it. This month we have tips for young tree pruning. Many new houses in newer developments come with a tree somewhere in their yard and one in the right of way strip in front of their house. Just a reminder that Berthoud Town Code states that the adjacent property owner is responsible for the maintenance, care, removal, and replacement of the street trees adjacent to their property. Pruning younger trees is easy if you have a plan, small pruning tools like hand pruners, loppers, and a hand saw or pole saw, and keep some basic principles in mind while pruning.
Consider the following:
• Your pruning objectives. One big one to consider especially for trees that might eventually grow over the sidewalks or road is that Berthoud Town Code states that tree branches will be cleared up to 14 feet above roads and 8 feet above sidewalks. If a branch is growing toward your house, low over your driveway, or in front of your perfect view from your favorite window, pruning it off while it is young will be better for you and the tree in the long run.
• Pruning Dosage: A rule of thumb is to not remove more than 25% of a tree's healthy foliage in a year. This is where it is good to have a plan of how you want your tree to develop so you can plan to take a certain amount off each year to reach your objective.
• The age of your tree. Freshly planted trees within their first or second year should not be pruned or have minimal pruning done. If any pruning should be done on newly planted trees, only remove dead or diseased branches. The tree uses every one of its leaves to help grow its root system and develop its branches and trunk. When we take away branches we can slow the growth of a tree. An established tree can more quickly overcome the stress of pruning rather than an unestablished tree still struggling to set its roots.
• The shape of your tree. Some trees naturally grow with a strong central leader and good structure, while others grow strongly towards whatever branches are receiving the most light. One thing to keep in mind is to try to maintain a single central trunk as far up the tree as you can. This can be tough as the tree grows taller and out of reach of long tools and ladders, but whatever you can do while the tree is young will massively benefit the tree in the long run.
• Temporary and permanent branches. On young trees, some of the lower branches might be around waist to chest high. This would obviously not make an ideal tree to mow or move around so consider which branches will be eventually pruned off, and which branches will be the start of the tree's mature canopy. Consider mowing under your tree, or people walking on the sidewalk underneath your trees canopy. It's best to not have a branch that low that will eventually become larger as the tree grows, which will lead to a large pruning wound in the future. For trees with branches growing towards the sidewalks and streets in town, it is best not to have a permanent branch below 8 feet if its growing towards the sidewalk, and below 14 feet if it is growing toward the street. The lowest permanent branch on most mature trees is 6 to 8 feet up the trunk.
Taking these considerations into mind when looking at your tree will help you plan out small pruning projects throughout the years that are easy to manage, rather than trying to manage all of these problems in one large pruning that could stress out the tree.
Links for extra information
Tree Planting Steps
**If you have any questions about this topic or about your tree in general, don’t forget you can email the Berthoud Forestry Department at forestry@berthoud.org , or call them with questions at (970)-532-4256 and leave a voicemail. **
April signals the start of tree planting season for the year, so for April's monthly tree care tip we are going to give tips on how plant a tree. While it may seem like a straightforward task, the Forestry Department wants to give some tips to plant trees like a pro, and steps to never avoid.
Right Plant, Right Place
Before even heading to the nursery and getting out the shovels, give the site you want to plant a tree some consideration. All plants have different environments they thrive in and matching the plant to that environment will ensure you have a healthy, productive plant. Consider if the site gets a lot of reflected heat from nearby buildings or structures, or if the site is in a low area, or drainage area where the soil might stay consistently wet. Is the spot sheltered or unsheltered from the wind. There can be many environmental factors at play for a specific site, but if you do your research on the type of tree that tolerates those conditions, it will start the tree off on the right track. If you are having trouble picking the right tree for your location you can always reach out to the Forestry Department at forestry@berthoud.org , or call them at (970)-532-4256 for suggestions.
Call 811 before you dig
Dont forget to call 811 before you dig. Calling 811 or visiting https://www.colorado811.org/ to submit a dig request will make sure you don't accidentally dig into any underground utilities while planting a tree. Pro-tip: https://www.colorado811.org/ has a tool specifically for residents where you can find your property on a map and place a pin right where you want to dig and it goes into their locates system. Hopefully no need to call and wait!
For tree planting in the Right of Way strip
Just a reminder that if the tree to be planted will be located in the Right of Way strip adjacent to your house between the sidewalk and the street, be sure to fill out a quick Street Tree Work Permit on the Town's Forestry Webpage to let us know what tree you chose to plant. There is a list of Prohibited Street Trees that can also be found on the Forestry Webpage under the dropdown marked "Prohibited Street Trees". We ask that these tree be not planted in the Right of Way as they are trees with known problems that make them bad candidates to line streets.
Tree planting season
Spring is a great time to plant trees but it is not the only time to plant trees in Colorado, Fall can be another great time to plant trees if you miss the spring planting window. We suggest trees are planted anytime the soil is not frozen in the winter. We also recommend not planting a tree at the height of summer heat as it is hard for a tree to overcome the stress of transplanting on top of the stress from hot summer days. Planting in summer can be done, but the tree will need consistent after-planting care.
Steps for planting a tree
Now that we have the right tree for the space we are putting it in, called 811 and are clear to dig, and submitted a Street Tree Work Permit (if applicable), lets jump into the planting steps.
1. Determine the depth of the planting hole
This may seem like a simple step but this is a step we see commonly done wrong. Pro-Tip: Getting the planting depth of a new tree is so important to the tree's survival in the years following planting, and for the tree structure in the long term. The most important thing in this step is to find the tree's root flare. It is common for trees coming from a nursery to have their root flare buried in the transplanting process. The tree's root flare is the tree's natural transition from the trunk of the tree to the roots.
Below is an example of what you might see in a container-grown nursery tree. Notice the trunk does not widen at all where it meets the soil.
After clearing away some of the mulch, the root flare is still not visible.
Dig away soil until you find the trunk starting to widen on all sides, once you find the root flare this is where the top of the root ball should be at. In this example 1 1/2 to 2 inches of soil needed to be cleared to find the root flare. You can start removing the soil off of the top of the root ball until the soil in the container/rootball is level with the root flare.
This soil buildup on the top of nursery rootballs is why we see most trees planted too deep.
Once you have found the rootflare and adjusted the size of your rootball, then you can determine the planting hole depth. Ideally, the top of the root ball will be planted right at soil level, or slightly above the soil level, never lower.
2. Dig a wide saucer-shaped planting hole 2-3x the diameter of the root ball.
You can measure the width of the rootball in its container/wrapping to determine the width of the planting hole. Wider planting holes are ideal in clayey Colorado soils as they give the tree roots a larger planting hole to establish their first permanent roots. Below is a reference chart to determine the planting hole depth and width.
Pro-Tip: Once the planting hole is dug, stand in the middle of the planting hole and stomp down the area where the tree will be placed. This stabilizes the ground under where the rootball will be placed to ensure the tree does not shift or sink in the planting hole as the soil settles with frequent watering.
3. Set the tree in place and remove the container/wrapping.
Depending on how big the rootball is sometimes it can be easier to just cut the container off in the planting hole. This is also a great time to inspect and adjust the fine roots of the tree before filling in the planting hole. Trees grown in containers have a higher chance of having roots that circle the container when compared to balled and burlap trees. Pro-Tip: Addressing any circling roots now is really the easiest time you will have fixing this potentially dangerous and sometimes fatal condition for trees. Below are some examples for how to deal with circling roots on the tree's root ball.
A root ball with severe circling roots will look something like this.
Cutting the roots vertically from the bottom of the root ball to the top in multiple areas around the rootball will cut roots long roots that go all the way around the pot.
Using a hand saw to shave off the outer layer of roots all the way around the root ball will disrupt long circling roots.
Teasing the roots on the outside of the rootball with your fingers or a hand rake disrupts the circling of the roots, orienting more roots to grow away from the tree.
If circling roots are not addressed during planting these can be extremely hard to deal with as the tree grows older. Below is a picture of a tree that was planted without disrupting the circling roots. As tree roots grow they grow in size and get woody. If this tree were still in the ground the roots would eventually cut off circulation of water and nutrients to the trunk, and also cause stability issues as the tree above grows larger.
4. Backfill the hole
Now that the circling roots are corrected and the hole is the right size you will want to start filling in the planting hole. Use the soil from the hole that you just dug. Be sure to break large clods of soil into smaller clods as you are filling in the hole. If the planting hole depth is perfect the top of the root ball should be visible slightly above or right at grade with the replaced soil in the planting hole. Pro-Tip: Add a few inches of soil into the planting hole and then add water which will help settle the soil and water the tree in the process. Repeat as you add more layers of soil back into the planting hole. Once all of the soil is added and watered in, it should settle most of the soil, and the tree should be thoroughly watered in. Below is a diagram of ideal root ball placement in the planting hole.
To amend or not to amend the planting hole. A big question we get is do you want to amend the soil you are adding back into the planting hole. We suggest adding nothing but the original dirt and water to the planting hole. The thought process here is if we amend the planting hole with potting soil, or other nice bagged soils, or add fertilizer we are actually encouraging the tree roots to thrive but only within that planting hole that has been amended. It is better for the tree to root out into the native Colorado soils and start seeking its own nutrients and water as this is the true nature of most plants and trees. When we give it everything it needs in one small place, it will not be too influenced to root out of its planting hole as quickly as compared to if it is all the same type of soil.
5. Staking the tree
We recommend staking the newly planted tree with 2 stakes on opposite sides of the tree. Be sure to pound the stakes just outside of the planting hole in undisturbed soil so the stakes do not move as the planting hole continues to settle. Strap the tree to the stakes with cloth straps. Other types of straps can be used like wire or plastic, but just make sure where these straps touch the tree bark they are covered with something soft so the hard strap material does not dig into the tree's bark, causing scarring. A piece of rubber or even an old rag can be placed around the part of the strap that will touch the bark and this should help. Tie the straps with a bit of slack in them. Remember that these straps are not keeping the tree still, only to keep it from blowing over in intense winds. Slack in the straps allows the tree to sway naturally in the wind which helps develop the strength of the roots and build up trunk taper. Pro-Tip: Always remove the tree straps and stakes after one year (two years tops in very windy planting sites)
6. Mulch
Be sure to add mulch over the disturbed soil of the planting hole but avoid placing mulch right on the top of the rootball area. Mulch helps retain moisture in the planting hole that the tree will need throughout its first year after planting. Mulch about 2-4 inches deep is ideal for moisture retention, temperature moderation, and weed suppression.
Other post-planting tips:
- Only prune dead or dying branches off the tree after/during planting. This young tree will need the entirety of its canopy to collect energy to start its establishment in its new location.
- The planting hole might settle as the tree gets watered through the following growing season. If the soil around the rootball is lower than when the tree was planted, pull back the mulch and just add some more soil in the sunken areas. Replace the mulch.
- When mulching be sure to try to leave the top of the root ball uncovered with fill dirt and mulch. If mulch does cover the top of the root ball that is ok, just make sure it is not piled up around the base of the trunk. This can cause moisture buildup at the base of the trunk leading to rot or might encourage rodent damage at the base of the tree.
Links for extra information:
CSU Extension - Tree Planting Steps
Front Range Recommended Tree List
TREE PESTS AND PROBLEMS TO LOOK OUT FOR
**If you have any questions about this topic or about your tree in general, don’t forget you can email the Berthoud Forestry Department at forestry@berthoud.org , or call them with questions at (970)-532-4256 and leave a voicemail. **
With trees and plants emerging in the spring, so are pests and problems that prey on our trees. This month we wanted to cover tree health in broad strokes to inform you if your tree needs to be looked at by a certified arborist.
There are many different pests and diseases that will affect trees so to cover a lot of ground on the topic this month, we are going to break down some common symptoms we see on unhealthy trees, and which ones are mostly nuisances, and which ones need to be addressed as soon as possible.
| Severe symptoms that can be fatal | Nuisance conditions, severity can depend on percent of tree effected |
|---|---|
Decomposer insects (detritus eating insect) - Presence of detritus eating insects like spring-tails, earwigs, and pill bugs do not harm trees, rather eat the dead organic matter that accumulates on trees. However their abundance in one particular area on a tree might indicate a spot of dead tissue. | |
**If you have any questions about this topic or about your tree in general, don’t forget you can email the Berthoud Forestry Department at forestry@berthoud.org , or call them with questions at (970)-532-4256 and leave a voicemail. **
Summer tree watering tips
Whether you have a large mature tree, or a new recently planted tree, keeping your tree well watered is key to a healthy and strong tree.
Starting off with some quick tips:
- Amount: General rule of thumb is to apply 10 gallons of water per inch of trunk diameter per watering. Try water a tree with this amount of water 2 times per month. For example a 2 inch caliper tree should get 20 gallons of water. 15 inch caliper trees should be getting at least 150 gallons of water.
- Where: Try to apply the water to the roots that need it the most. The fine roots a tree are responsible for most of the trees uptake. Another rule of thumb is most of these fine roots are located near the trees drip line, which is generally around where the trees canopy ends.
- How: Applying water slowly when watering a tree helps the water penetrate deeper into our soils which will influence the tree to sends its roots deeper. Deeper roots lead to a more structurally sound tree.
Correct summer watering practices on trees is essential for keeping your tree healthy. Colorado’s climate is known for being dry and hot which can be hard on all plants not adapted to drought conditions. Long periods without water can stress trees. A stressed tree has less stored energy to deal with other health conditions, or resisting pests. A single dry year might not kill a tree, but multiple years of receiving inadequate water can send your tree into a downward spiral of health, which could potentially kill the tree.
One important thing to consider is watering where the tree will need it the most. Focusing putting water down on the fine roots of the tree. As roots get bigger they get woody and are more responsible for structural support and nutrient transport rather than water uptake. Focusing water on these woody roots is not as effective for water absorption. A rule of thumb is most of these fine roots start around the drip line of the tree. A drip line on a tree can be visualized by drawing an imaginary line from where the edge of the trees canopy ends, all the way down to the ground. If using a hose or hose end sprinkler, placing the end of the hose on the dripline or just outside the dripline is ideal for getting water to the fine roots.
One unique problem we run into with mature trees in the urban setting is that most of the root zone for a tree might be underneath impermeable surfaces like roads and driveways, or they might be in areas out of your control like in your neighbors yard. If you still are able to keep the soil moist around the tree that you can control, it is better than nothing.
Watering technique is important for tree watering in our clay soils. Try to apply the water slowly so the water penetrates into the soil rather than running off site. When we practice deep watering techniques on trees the water moves deeper in the soils which influences the roots to grow deeper. Deeper rooted trees can tap into moister soils deeper down and can be better adapted to drought. Deeper roots can also mean a more structurally sound tree. When a tree has shallow roots, it can be less structurally sound in high winds when compared to a tree with a deeper rooting system.
Trees in lawns with sprinklers should get enough water if the watering times on the zones are long enough. But consider the last point. When we use sprinklers to keep our lawns green, its usually just enough water to keep the grass green, which don’t extend too deep into the soil. If you set a program on your sprinklers to water much longer than usual you can get that water to soak in deep into the soil and achieve that deep watering.
Newly planted trees will need more frequent watering during the summer as they are still establishing their root systems. Water 2-3 times a week to keep the root ball and the rooting area moist for the developing roots. Once the tree is established you can ease up on the watering a bit, and switch to watering the tree once a week, then to every other week. Lawns with sprinklers can help maintain soil moisture for younger trees, but do not let the rootball of the tree dry out in its first year. Another thing to consider with young trees is you can actually kill a tree with overwatering. Water at intervals where the water soaks into the soil completely and water at intervals where the soil has some time to dry out a little bit in between waterings. When soils remain completely saturated with water, the oxygen levels in the soil get depleted and your trees or plants may drown. Remember that plant roots need oxygen as much as we do for proper growth.
Avoid waterlogging your soil by allowing any standing water to percolate into the soil between watering.
Extra links for more information:
**If you have any questions about this topic or about your tree in general, don’t forget you can email the Berthoud Forestry Department at forestry@berthoud.org , or call them with questions at (970)-532-4256 and leave a voicemail. **
Mulch might seem like a small detail, but it plays a big role in tree health—especially in Colorado’s hot, dry summers. That’s why we’re dedicating this month’s tree care tip to mulching: how it helps, what to use, and what to avoid. Whether you’re caring for young saplings or mature landscape trees, proper mulching can make a huge difference in water conservation, root protection, and overall tree health.
July in Colorado can be hot and dry, sending many of us to pools or lakes to cool off, or maybe fill our coolers with cool refreshing drinks. Trees can also struggle with the heat of the summer, but they could use our help keeping cool and hydrated as well. Proper mulch can help trees, especially young trees get through even the hottest summers.
One of the biggest benefits of mulching around the base of any plant is water conservation, and helps keep soil temperatures stable. When we apply mulch around the base of young trees, the mulch takes most of the heat from the direct sunlight and dissipates it before it reaches the soil at the base of the tree. This means that the soil around the roots stays cooler, and does not lose as much water from evaporation, leaving more moisture for the tree’s roots. One of the biggest benefits of mulching around the base of any plant is water conservation in the soil, and helps keep soil temperatures nice and cool.
On newly planted trees an ideal sized mulch ring is as wide as the planting hole. As the tree establishes and grows bigger, ideally the mulch ring should grow wider as well, but that might not be feasible in most residential landscapes so at least keeping the mulch ring the size of the original planting hole will still retain some secondary benefits as the tree grows larger.
Another benefit of adding mulch around the base of trees and landscape plants is weed suppression. To many of with landscapes we care for, it might seem like this is untrue, and that the only place we find weeds in our yards is in the mulch. For mulch to be effective for weed control it should ideally be 2-4 inches deep. You might need to re apply mulch yearly or every other year as it breaks down or gets pushed into the soil. Avoid layering new mulch on top of old without checking for buildup. Try to always keep in mind that 2-4 inches of mulch is ideal.
Mulch rings made of organic material such as wood chips, dried grass clippings, leaves, pine needles, hay, even shredded newspaper, cardboard or agricultural byproducts all have the added benefit of being able to broken down by insects and micro-organisms to feed nutrients directly into the soil near the root zone of the plant. Consider it free soil conditioning and fertilizer!
Some mulches might be made of inorganic material that don’t break down, but they still give the benefit of keeping the root zone cool, suppressing weeds, and retaining soil moisture, if applied at the right depth. Some examples of inorganic mulches might be gravel or rocks, chipped rubber, landscape fabric, or even landscape stones like pavers or sandstone. While they might last longer than organic mulches, they do not contribute nutrients to the soil like organic mulches do. Another potential downside of some inorganic mulches like landscape fabric or plastic sheets is that they can block out oxygen and water from getting into the soil which are both equally important to plant roots for health. Organic mulches are always preferred over inorganic mulches.
One benefit of mulch people might overlook is that is can reduce mechanical damage to the trunk or base of the tree. If you have applied mulch around the base of the tree at the right depth, and it is properly suppressing weeds and grasses. When you or whomever you hire to maintain your lawn or weeds comes through with a mower or weed whip, the ring of mulch around trees acts as a great buffer that should keep tempted mowers and weed whips away as we all want to get those last couple blades of grass or weed right next to the trunk. Keep in mind, one of the most common causes of death we see on young trees is from weed whip or mower damage damaging the base of the tree. Remember that one significant strike to the truck of a young tree might never fully heal, a smaller tree might not be able to take so many accidents before its becomes fatal.
There are some considerations of what to avoid when mulching trees.
- “The Mulch Volcano” Avoid piling mulch right up next to the trunk of the tree. This traps moisture next to the base of the tree which can encourage rot and diseases to fester at the base of the tree. It can also encourage small animals to nest in it and they might feel tempted to gnaw the bark of the base of your tree. Always keep the root flare (where the trunk widens at the base) exposed, buried flares are a common cause of decline in urban trees.
- Using too much mulch can start to suffocate the roots by reducing oxygen flow to the roots.
- Don’t use fresh grass clipping as mulch if that is your mulch of choice, try to use dry grass clippings instead. Green grass clippings might mat down and block the flow of air and water, and can also start to stink over time.
- Apply mulch without prepping the soil below. If you apply mulch over weeds or grass, they might continue to grow through the mulch. Try to remove any weeds and cut out sod where you want to lay down mulch to ensure the area will remain mostly free of weeds.
- Don’t us mulch that you know is contaminated with pests, herbicide, or pests.
Example of a "mulch volcano"
**If you have any questions about this topic or about your tree in general, don’t forget you can email the Berthoud Forestry Department at forestry@berthoud.org , or call them with questions at (970)-532-4256) and leave a voicemail. **
Our urban forest canopy casts great shade when trees reach their maturity. However, when our trees reach their mature size and are towering above our houses, roads, and sidewalks, they can be dangerous if large branches, or worse, the whole tree were to fall. Large trees aren’t inherently dangerous, but with size comes risk. The good news is that, like most risks, it can be mitigated through proactive and thoughtful care.
Most hazardous tree conditions develop slowly over time. A small issue may seem harmless now but can evolve into a serious problem if left unaddressed. Fortunately, if caught early, many of these issues can be corrected with simple pruning or maintenance. Trained arborists are skilled at identifying early warning signs that could signal future hazards.
This month’s tree care tip is about recognizing potentially dangerous conditions in your trees—whether you’re caring for young saplings or mature giants.
Canopy Problems
Broken Branches – A broken branch in the canopy especially 30 – 50 ft overhead can be deceptively heavy. If the branch is partially attached it might be able to hang on longer than if it was completely broken off, but still should be removed promptly. Fully severed branches caught in the canopy are just waiting for the right wind to come loose and plumet to the ground. Even a cracked branch (with a visible split running along its length) is compromised and should be removed as soon as possible.
Narrow branch unions- Narrow branch unions can usually be seen by their close “V” shaped crotches. When branches develop in these narrow branch unions, they often have bark trapped between the growing branches (“included bark”) and are more prone to breaking under load. Some species of trees are more prone to growing with narrow branch unions than others. Pruning these out early, especially on young trees, can prevent major structural failures later.
Branch proximity- Look at that branches of your trees extend over high value targets, like your house or driveways, or where people might gather. These branches could be removed to completely mitigate the risk to targets below them, but it might not be necessary. While not every overhanging branch is dangerous, large ones can break and fall during storms, sometimes hitting other limbs on the way down and causing a cascading failure. Most branches without any sign of problems might be just fine, and might only need a little bit of pruning to lighten the weight of the branch.
Trunk/Whole tree problems
Lightning strikes – While uncommon, lightning can cause severe damage a tree. The high energy bolt of lightning sears the living tissue of the tree all the way to the ground leaving a long path of dead tissue from the canopy to the roots. While the tree might not die from a lightning strike, the wound may never fully heal and open a large wound over most of the tree that can become infected with bacterial or fungal organisms that rot the wood of the tree leading to the overall structure of the tree being compromised over time.
Hollow cavities in the trunk – Visible hollow cavities in the tree trunk could indicate extensive internal decay. These hollow cavities might allow rain and snow in which helps fuel the wood rotting organisms, making the rotted cavities worse over time. Even animals nesting in the hole might be making the problem worse.
Excessive bark peeling – If bark is loose and comes off the trunk in large chunks, it may indicate a large section of the cambium (the tree’s living tissue) of the tree has died. This can expose the heartwood, which, if rotting, can severely weaken the tree.
Mushrooms growing from the tree – While conks or mushrooms growing from the trunk of the tree may seem whimsical, the fungus is actually feeding off of the wood of the tree. A mushroom is a fruiting body of the fungus and could indicate a healthy fungal colony feeding off the wood of your tree. Mushrooms near the roots or root flare should not be taken lightly, it may signal significant internal damage.
Root problems
Sudden leaning/heaving soil near base – If your tree has developed a lean in a short period of time or you see the soil heaving below it on one side, it could be an indication that your tree roots are becoming unstable and the tree is shifting because of this. If this problem occurs over a short period of time like within a year, it should raise concern and an arborist should be contacted.
Major damage to roots – Construction near the tree’s base can damage critical roots, reducing the tree’s stability. Mature trees rely heavily on their root systems for anchoring; if that’s compromised, even healthy trees can become hazardous. Major root damage is a big concern for mature trees, but can be overcome if the tree is healthy and its roots are given optimal water and growing conditions to recover and reestablish.
Other concerns to look out for
Borer damage or increased woodpecker damage – Wood boring insects can kill large branches and parts of the tree if they are infesting parts of the tree. Woodpeckers target infested areas trying to get at these larva and grubs of insects just underneath the bark of the tree. If you see woodpeckers frequently visiting your tree and focusing on a specific area, that might indicate that there is a population of insect larva underneath the bark they are trying to get at. The woodpecker damage is not what you should be concerned about, it is the insect larva damaging the tree just below the bark.
What to do if you see these hazardous conditions on your tree.
Don’t wait! Contact a Certified Arborist as soon as possible for a professional assessment. A leaning tree, a large crack in the trunk, or broken hanging limbs can all be early indicators of much bigger failures. Trees rarely recover from these problems on their own—and they almost always get worse over time. Being proactive can mean the difference between a minor pruning job and a major removal or property damage. Spotting small signs early gives you the best chance to intervene before failure occurs.
External links for more information
University of Florida - Structural Defects of Trees
https://hort.ifas.ufl.edu/woody/structural-issues.shtml
ISA Rocky Mountain Chapter - Identifying Damage
https://isarmc.org/identifying_damage
Signs of stress in trees
**If you have any questions about this topic or about your tree in general, don’t forget you can email the Berthoud Forestry Department at forestry@berthoud.org , or call them with questions at (970)-532-4256 and leave a voicemail. **
This months tree tip is what symptoms to take notice of in your trees as they may be an indication your tree is stressed. Some of these problems to look out for overlap with the May Tree Care Tip, but the difference between the two is if these problems happen year to year on your tree, there might be an underlying stressor causing them.
If caught early enough, some of these problems and their underlying causes may be corrected and the tree might look healthier.
Early fall color and leaf drop – It might not jump out as a sign of an unhealthy tree, but is definitely apparent when a tree starts getting its fall color earlier that other trees on the block, especially compared to similar species of tree. Early fall color doesn’t necessarily mean it is the first tree to change color around when other trees are starting to change color in fall, but if its getting its fall color a month earlier than other trees, often defoliating by the time other trees are starting to change color. Common stresses that lead to a tree getting an earlier fall color include, water stress, heat, or even root stress.
Year after year leaf conditions - If your tree has weirdly shaped, or damaged/dying leaves year after year, it could be a sign of underlying stress. Depending on what symptoms the leaves are showing, it could be a sign of water stress, heat stress, salt damage, root stress, or insect damage. There are many different ways leaves will look damaged so it is best to get a picture of the effected leaves and reach out to an arborist to help you diagnose the root of the problem. They might ask you many questions about the tree, like any significant damage in the past 5 years, or what supplemental watering you supply to the tree. Onsite visits are helpful for arborists to get a full picture of the area the tree is growing in and what possible stress it is under in that area. Most of these conditions are gradual declines in the trees health, so it is important to note not only happened to the tree this year, but also a few years back.
Chlorosis – If your tree has a condition called chlorosis, the leaves will have green veins throughout the leaf, but the majority of the leaf tissue between the veins will be yellow or white. This is a condition causes by the tree not uptaking enough iron to grow normal leaves. Chlorosis is very prevalent in Colorado in certain tree varieties. The problem usual comes from the high pH soils found in Colorado. When the pH of the soil is high, the iron in the soil becomes unavailable to uptake by the tree roots. Treatments and remediation of this condition are not so much a tree problem as they are a soil problem, and the methods to bring down the pH of the soil in the trees root system are often expensive and extensive treatments with no guarantee it will reflect in a healthier tree.
Sparse canopy- If the canopy on your tree has been getting thinned out year after year and not looking as full as it once was, it might be a sign of drought stress or root damage.
Poor growth or no growth- If your tree hasn’t shown much progress in growth year after year, it might be an indication something is disrupting is normal functions. The underlying causes could be water stress, trunk damage, root stress, root damage/disruption, or disease. All of these stresses can disrupt the tree’s ability to collect water and can also disrupt the flow of water and nutrients in the tree. A way to see how much a tree grew is by looking at a branch tip and looking for where the terminal bud scar was in the previous year compared to where the end of the branch is in the current year. Below is a picture of what to look for on a branch to determine to amount of growth in a given year.
Branch tip die back- Branch tips or whole branches dying is a common problem that can be caused by many different stresses on the tree. Like with leaf conditions, take pictures of the scale of damage on the tree, and make notes of known previous problems the tree might have had and consult with an Arborist. Branch tips/branches dying could be caused by root damage, improper planting depth, girdling roots, not enough water or too much water, diseases or insects, freeze damage, or trunk damage. Some causes of this symptom might not be attributed to stress, rather a single event like storm damage breaking a branch, or if the branches dying are in the interior or constantly shaded out by a nearby house or tree, the tree might be shedding the branches as they are not productive to the tree anymore.
Suckers or Water sprouts- If you notice an abundance of waterspouts or suckers growing on your tree, most likely it is a response to stress. A tree sends out waterspouts or suckers when the tree is trying to compensate for a recent injury like root damage or over pruning.
For Evergreen (coniferous) trees- Browning needles – Needels on conifers turning brown and dropping near the inside of the tree is normal as the tree abandons needles that are not longer productive for the tree. However, if the needles are browning all over the tree and all the way to the branch tips this could be a sign of water stress. Keep an eye out for needles turning brown across the whole branch especially in the winter as it might be a sign the tree does not have enough water. Evergreens can still photosynthesize with their green needles throughout the winter, so they need to have their root systems kept moist year-round.
Concerning needle browning on conifers- needles browning from the tips.
Normal needle browning on conifers. From the inside, the oldest needles on the branch start to brown and drop.
Many of these problems might have “water stress” as a cause, this can mean either the issue is caused by not enough water or too much water for the tree roots. When watering a young, or mature tree, be sure the water has had enough time to infiltrate into the soil and move through the soil before watering again. Here in Colorado, it can be very easy to overwater a tree because our soils are notoriously high in clay content which holds onto water for longer than other soil types. If you are unsure if the stress effecting your trees if from overwatering or underwatering, if you can hear sloshing or squishing when walking over the soil in the root system, it might be overwatered. Water might also be visible coming out of the soil when you walk on it. Let the soil dry out if it gets this wet and try to adjust the watering cycle on your tree to apply less water.
Fall Watering and Tree Wrap
**If you have any questions about this topic or about your tree in general, don’t forget you can email the Berthoud Forestry Department at forestry@berthoud.org , or call them with questions at (970)-532-4256 and leave a voicemail. **
October usually marks the time of year that most properties are blowing out their irrigation systems as freezing temperatures are right around the corner. Since Colorado falls can have unreliable precipitation, keep in mind your trees will still need water even after dropping all of their leaves.
In anticipation for shutting down your irrigation system for a winter season, while your system is still operational, set some days to run longer than the usual program times you have set throughout the summer. This should get a good amount of water into your soil and give the trees and other landscaping plants some deeper water reserves to tap into as fall progresses. If you have been practicing deep watering for your tree throughout the summer this might not be as crucial to do.
Fall and winter droughts can be especially rough on trees and plants since the daytime temperatures can still remain relatively high, some plants might still have green leaves attached, fall winds start picking up which dry out plants further, all while our reliable irrigation systems have been turned off. After your irrigation system has been shut down for the winter, pay attention to the weather and where your trees are in their transition into dormancy. One big thing to remember is if a trees leaves are still green and flexible, the tree still needs water to carry out photosynthesis.
Try to water your tree near the drip line every two weeks in the fall if it still has green leaves, and when it has dropped all of its leaves it is ok to spread out the time to watering to about once a month. Keep up with this watering practice until we get some decent precipitation. If freezing temperatures arrive before any significant snowfall occurs, apply water in the middle of the day on days above 40 degrees so the water can actually soak into the thawed soil.
Keep in mind that if precipitation comes as snow, 10 inches of snow is equal to about 1 inch of rain depending on the snow consistency.
Tree Wrapping
One other tree care tip we would like to highlight this month is October is a perfect time to wrap younger trees for the winter. Wrapping younger trees with thin bark helps reduce their chances of getting a condition called sunscald. Sunscald effects young trees with thin bark. Permanent damage occurs when the sun heats up the south side of trees during the days during the winter causing rapid temperature fluctuations on the bark from day to night. These drastic swings in temperature can cause the living cells under the thin bark to die leaving a large section of dead tissue on the south sides of trees. As the tree grows older these wounds can be very large and never heal properly so it is important to take this small step to avoid this damage.
Two examples of sunscald damage on trees.
Wrapping your tree is not a difficult process, all you need is a roll of tree wrap paper or cloth, and something to secure it to the tree, usually tape or staples. For homeowners with a new tree with thin bark, we recommend getting a fabric tree wrap since it can be used year after year. Tree wrapping paper can be sold in large rolls with up to 200ft of wrap which should also last a single tree well into its maturity when it does not need to be wrapped anymore. Proper paper tree wrap is like crepe paper with a bumpy texture. Ideal colors for tree wrap fabric or paper is either brown or white, never use dark colors that will absorb and retain heat during the day.
Paper tree wrap (left) Cloth tree wrap (right)
To wrap a tree, start the wrap as close to the ground as possible wrapping up the tree in a clockwise or counterclockwise direction. When you get the wrap around the tree once where it is covering the start of the wrap, make sure it is nice and snug and tight and continue wrapping around the tree up to the first branch. When you get to the lowest branch cut the paper or tie the remaining fabric around the tree. To secure the wrap, either tape over the paper by going around the tree a couple times with either duct tape or electrical tape, cut and secure. If using fabric, if you have enough extra to tie the extra around the tree and into a knot this might be enough to hold it in place. If there isn’t much fabric left over either staple the fabric to itself or pin it to itself with a safety pin. Do not staple the fabric or paper to the tree. If the wrap is on the tree tight enough near the bottom it should hold the bottom in place just fine, but it is ok to wrap the bottom with some tape or pin it if you are not sure. When it comes to removing the wrap in the spring, if you used tape, cutting the tape is often the easiest way to remove the wrap, just make sure you cut shallow enough that you do not cut into the tree bark.
If you are unsure of what a thin bark tree is compared to a normal bark tree, first off, it never hurts to wrap any young tree, it will not hurt a tree with thicker bark if it is wrapped. Thin barked trees include apples, chokecherry, lindens, some oaks, birches, beeches, pears, maples, serviceberries, redbuds, honey locust, tree lilacs, and elms. Basically if the tree bark doesn’t have a lot of 3D texture it is a thin bark tree. As all of these thin bark trees age they start to develop more ridges and furrows in their bark which helps them naturally regulate temperatures under the bark. Once the majority of the trees trunk is covered in this texture bark the tree will not need wrapping anymore.
Smooth bark of a young linden tree. Mature linden tree bark with more texture.
External links for more information
CSU Extension - Fall and Winter Watering
https://extension.colostate.edu/resource/fall-and-winter-watering-of-plants-and-trees/
CSU Extension - Tree Wrapping
https://extension.colostate.edu/resource/wrapping-trees-for-winter/
November - Freezing temperature tips for trees
**If you have any questions about this topic or about your tree in general, don’t forget you can email the Berthoud Forestry Department at forestry@berthoud.org , or call them with questions at (970)-532-4256 and leave a voicemail. **
November is a time when most trees should be fully dormant and we have some more winter care tips for your trees. As mentioned in the October monthly tree care tip, always be mindful of how much water your trees are getting from snow or rain, and supplement with winter watering practices. Also, by November any young, thin bark trees should be wrapped to prevent sunscald.
While winter has slowed everything down, it is good to keep up on routine tree maintenance. Winter is a good time to make sure the mulch around the base of the tree is adequate, about 2-4 inches deep and pulled away from the trunk. Maintaining this mulch layer into the winter keeps the any moisture in the soil longer. This is easier, and more important on younger trees that are still susceptible to drying out during the winter.
Natures mulch and fertilizer
Fallen leaves can be used as a natural mulch and soil amendment. Leaves collected with a lawn mower are already shredded and easy to spread beneath trees and garden beds. Even leaves mulched directly into the lawn can improve soil health as they break down slowly over winter and release nutrients.
Start thinking about pruning
Winter is generally the best time to prune trees, but November may be too early for some species that are still entering dormancy. This is a good time to inspect trees and identify broken, damaged, or poorly placed branches that may need removal later in winter. Refer to February and March tree care tips for guidance on proper pruning timing and techniques.
To help assess dormant branches, gently bend small twigs on a day above freezing. Living twigs are typically flexible, while dead twigs are brittle and snap easily. Check multiple twigs before deciding whether a branch is dead.
If results are unclear, a bud can be carefully pinched and split open. A healthy bud is usually green and moist inside, while a dead bud is dry or crumbly. Use this method sparingly and avoid buds at the very end of branches, as this can damage future growth.
De-Icing Products and Tree Health
Use de-icing products sparingly near trees and planting areas. Salts can accumulate in soil and cause long-term damage to trees and other plants. Rock salt (sodium chloride) is particularly harmful and should be avoided near vegetation.
Some alternatives, such as magnesium chloride or calcium magnesium acetate, are generally less damaging to plant roots. Many products labeled “pet-friendly” use compounds that are safer for soils; however, all de-icers can cause damage if overused. Evergreen trees and lindens are especially sensitive to salt exposure and may show needle or leaf tip burn.
Front Range soils are prone to salt buildup, and removing excess salts can take years, so moderation is key.
Strategic Snow Placement
When shoveling snow from sidewalks or driveways, snow may be placed around the tree’s drip line—but not directly against the trunk. Snow can provide temporary insulation for roots and release moisture slowly as it melts.
This technique is most appropriate when temperatures are expected to warm after a snowfall. Avoid piling excessive amounts of snow over root zones for extended periods, as compacted snow and ice can limit oxygen in the soil and stress tree roots.
External links for more information
Colorado State Forest Service & CSU Extension - Fall Tips to Prepare Trees for Winter
December – Winter Watering tips for Colorado
**If you have any questions about this topic or about your tree in general, don’t forget you can email the Berthoud Forestry Department at forestry@berthoud.org , or call them with questions at (970)-532-4256 and leave a voicemail. **
Winters in Colorado can bring some of the worst drought conditions. These drought conditions might not seem severe with cooler temperatures and the occasional dusting of snow but they can result in long periods without significant precipitation.
As noted in the October Monthly Tree Care Tip, approximately 10 inches of snow is equal to about 1 inch of rain depending on snow consistency. While the occasional light dusting of snow might appear beneficial, it does not amount to much for plants. The Berthoud Forestry Department would like to highlight the importance of winter watering in December’s Monthly Tree Care Tip.
What trees and plants need it the most?
All plants can be damaged if their root systems dry out during winter droughts. Some plants are more susceptible than others, including:
- Recently planted trees and plants as their root systems are not robust and fully formed yet.
- Evergreen plants like conifers or other evergreen perennials. Keep in mind if the plant doesn’t drop its leaves or needles in the winter and stays green, it is still photosynthesizing in the sunlight and needs water.
- Trees in warmer areas. Plants on the south side of buildings might get more reflected sunlight which can warm and dry out soils more quickly.
- Trees in windy areas. Wind can accelerate moisture lost from evergreen and dormant deciduous trees.
When to winter water?
Water trees and plants when air temperatures are above 40°F. Apply water when the soil is not frozen solid.
A screwdriver test can be a good indication if soils are warm enough to water. If you can easily push a screwdriver into the soil, it is safe to water. Midday is usually the best time to apply water so it can soak into the soil before temperatures drop. If there has been no substantial snow accumulation over the month it would be good to water your landscaping.
This applies for all fall and winter months, from when irrigation systems are blown out to when they are started back up, typically November to March-April.
How to winter water?
When winter watering, apply water to root zones slowly to allow the water to penetrate deeply into the soil. Roll out a hose to the root zone or drip zone of the plant you are watering and turn it on to a very low flow.
For trees, try to move the hose around to a couple places around the drip line of the tree to get water to as much of the root system as possible. Do not water directly on the trunk or root flare of the tree. Soaker hoses are also a good option to apply water slowly over a large area.
How much to water during the winter?
Since most plants are dormant in the winter, you can use less water than during the growing season. On smaller trees 5-10 gallons of water should be sufficient and on larger mature trees using 20-30+ gallons is adequate. Watering once or twice a month is usually good enough for dry fall and winter months.
Mulching makes a difference!
Mulching plays and important role in tree health even through the winter. Proper mulch can help retain moisture in the soil and during the winter months proper mulch rings can also regulate soil temperatures and reduce freeze and thaw stress to roots. It is important to make sure mulch is not piled up around the base of the tree as excess mulch attracts burrowing rodents which gnaw at the bark of young trees, severely damaging them or even killing trees.
External links for more information
CSU Extension - Fall and Winter Watering of Plants and Trees