Fall Foliage Already? - Why Leaves May Turn Early This Year

Michael Sundberg, district manager of Davey's West Denver office, talks about early fall color on trees, as well as why it occurs, problems to look out for and how to treat stressed-out trees. 

In this episode we cover: 

• What were Denver's spring and summer seasons like this year? (0:50)
• Denver trees' response to a wet spring (1:40)
• What homeowners should know about leaf discoloration (2:14)
• Long-term affect of drought stress on trees (3:44)
• How to treat drought-stressed trees (4:38)
• Mulching for water retention (5:50)
• Michael's preferred mulch (7:02)
• Soil compaction (10:22)
• Air spading (13:20)
• Foot traffic can stress trees out, too (14:54)
• Linden trees (15:45)
• Does early color change always mean something bad? (16:47)
• Growing trees in Denver (18:33)

To find your local Davey office, check out our find a local office page to search by zip code.

To learn more about why tree leaves may change color and lose leaves early, read our blogs, Why Are Trees Losing Leaves in June, August or Early Fall? and Reasons For Early Or Dull Fall Color.

Connect with Davey Tree on social media:
Twitter: @DaveyTree
Facebook: @DaveyTree
Instagram: @daveytree
YouTube: The Davey Tree Expert Company
LinkedIn: The Davey Tree Expert Company 

Connect with Doug Oster at www.dougoster.com. 

Have topics you'd like us to cover on the podcast? Email us at podcasts@davey.com. We want to hear from you!

Transcript

Doug: Welcome to the Davey Tree Expert Company's podcast, Talking Trees. I'm your host, Doug Oster. Each week, our expert arborists share advice on seasonal tree care, how to make your trees thrive, arborists' favorite trees, and much more. Tune in every Thursday to learn more because here at the Talking Trees podcast, we know trees are the answer. I'm joined again this week by Michael Sundberg. He is the district manager of the West Denver Office of the Davey Tree Expert Company. Today, we're talking all about early leaf color in trees and what that means. Welcome back to the show, Michael. How's it going?

Michael: Thanks for having me again, Doug. It's been going great. I'm looking forward to fallout here in Colorado. It's always beautiful, and I always love the changing of the seasons.

Doug: Let's start there. Even before we start on the color changing, I wanted to ask you what your season was like this year. What have you dealt with this year?

Michael: This year was unique. We actually had more frequent spring moisture than we're used to. Almost weekly, it felt like it was raining throughout the spring, which is really good for tree growth. Then the faucet was turned off all summer. We've been dry and hot and droughty. Just like a lot of years have been recently. Not terribly, extremely hot, but just dry. Now we're finally starting to cool off. Still not getting a ton of moisture.

I'd say it's been almost like a normal year, except for we are just a little bit more on the wet side this spring. It's been fun to see how different that is for us, how the trees respond.

Doug: How did they respond?

Michael: We had a lot more growth on a lot of trees than we are typically used to seeing. Just that prime growth season actually had moisture, and so the trees were happy, and they put out a lot of leaves. In some cases, they put out way too many leaves than they could budget for once the summer heat set in, and they actually had to do some shedding. It was wild to see some trees have to roll it back once we stopped getting the moisture. Still beautiful out here.

Doug: That leads us right to our topic. Let's start off with when things do dry out, when we do get to this part of the season, but it's too early for traditional leaf color change. What should we be thinking of as homeowners if we look up at that tree and we start to see discoloration of the leaves or a change in the color of the leaves?

Michael: Yes, it's a great question. If you are starting to see some early fall color in your trees or your tree is maybe the only one in the neighborhood that's changing, it can definitely be a sign of distress, often circling back to the drought side of things. If trees are running dry for the year, they're going to end up having earlier fall color. They just don't have enough water to make all the resources they need, and they'll shut things down a little bit early.

Also, just construction stress or compaction of the soil, or other factors that will lead to early fall color. Pest and disease can also do that if any part of the plants are being damaged. Anywhere that the supply chain is broken up from the roots to the leaves is what will change first once the actual season starts to change. However, it'll be really early and drastic-looking if you get that fall color and the rest of the neighborhood is still really green. You've got a maple that's just crimson red. It's cool and beautiful still, but it's not the best sign for tree health.

Doug: It's obviously worrisome to anybody. Again, you're driving down the street, and you look at your yard, and you see that maple all changing color. Let's just assume for the first example here that it is because of drought conditions. Does that have a long-term effect on the tree, or is there anything we should be doing in that case, this late in the season?

Michael: Yes, it has a long-term effect on the tree for a couple of reasons. One is that a lot of things with the trees are really slow to show signs. You already have a problem that's been going on for a long time. If you're getting that color in the fall, the tree could have been running dry all summer, so that's a long-term problem, or you have compaction that's just happening year over year, or it isn't getting alleviated at all. You're getting that lagging indicator of the tree health as a long-term problem. Then, just looking forward, if you've had droughty years and you've got a compacted area, that also leads to long-term health problems for the tree going forward in the future. That's no good either.

Doug: I know you have to be on site to know exactly what's going on, but in this example we're using, in general, what would you be doing to a tree like that?

Michael: I would definitely try to get some more irrigation onto the tree for just however, the sprinkler system can be tweaked to get more water to it. Anything you can do to change the landscape to get more water out to the trees is going to help short-term and long-term. It's not going to just reverse your fall color. You won't go from red tree back to green, but at least maybe in the future years, you might be on a more normal color course and better tree health.

Things for compaction, you can do your usual lawn aeration can help on the surface level. You can do deep-root fertilization and watering services to actually probe into the ground and hydraulically fracture the soil. That allows some air to get in there and alleviate the compaction side of things. Then there's some things that are just tough to change. If you have a tree growing right along a street, it's going to have more heat and less favorable soil factors that are just going to be hard to correct. Really, you're just trying to make the tree as happy as it can be where it has to live since you can't move it easily. Yes.

Doug: Obviously, with that watering would come mulching too, I would think. If you're seeing a tree that you don't think is getting the water it needs, adding water is one thing to do. Certainly, to preserve that moisture would be mulching. As we say on every Talking Trees podcast, mulching the right way. [laughs]

Michael: Mulch is great. If it's not already part of the equation, it should be. It helps with that moisture side of things. Also, if you think about it as a nice little mat for the root zone, if it does get foot traffic or gets driven on, you've got that little spongy layer on the top to absorb a lot of the force. Really, it also helps with alleviating future compaction. You just want to make sure you don't volcano mulch, but I'm sure that's been talked about before.

Doug: We don't use the V word on Talking Trees podcast anymore. Yes, we do, actually. We talk about volcano mulch every other show because it's driving us all crazy. It shouldn't be happening, but we know it happens. As long as guys like you, Michael, and I are out there telling people don't do it, maybe someday we'll have a world without volcano mulch.

Michael: We can dream, right?

Doug: [laughs] What do you like to mulch with? What is your preferred thing to use for mulching?

Michael: I like all the bark material. I like the color. I like the smell. It's got a little bit of the maintenance side. You've got to fluff it or flip it over or replace it after a while, as it gets faded and dull-looking. I think nothing beats the original of just having tree material broken down on your soil. It adds a little bit of food to the soil, too, so you get some good feeding benefit. I don't blame people if they go with rock or anything that's more permanent and set it and forget it style. At least it's something. Anything beats bare soil to me. Yes, I'm a traditionalist. I go for the bark.

Doug: I have a friend that did his whole backyard next to his house where his perennials are in that stone. All I could think about is moving into that house and thinking, "How am I going to get that stone out of there?" [laughs]

Michael: Yes, if you're moving into it and you don't want it, it's a huge lift of labor to get the stone out and flip it. I moved into a house that had a bunch of the rubber tire mulch from an area. I got that out immediately because I don't even like the smell of that.

Doug: Oh, tell me about that job. Oh, that sounds absolutely awful, Michael.

Michael: Shoveling a wheelbarrow for a weekend.

Doug: What do you do with that stuff?

Michael: I just try to get rid of it, like every trash cycle, just bit by bit. Yes, it was no fun.

Doug: I don't even think you could use it at a playground or something, right? There might be environmental issues, I would think, with--

Michael: Yes, with the heat, and yes, just not my favorite.

Doug: Then the rocks, I know what you're saying. At least it's something. There's just something about having a nice layer of bark mulch on there. When you look at it looks great. It also is a weed suppressor, and it is really helping the tree.

Michael: Yes, I think it's the best. I love the smell too. After it rains or anything, it enhances the yard quite a bit.

Doug: There is something about it when you do go out after a rain. When we go through these dry periods, and I'm in the east, I'm in Pittsburgh, and we're in a drought here, which is relatively rare, although second season. The day that we get a good rain, it's such a relief. It's hard to explain that feeling. You know it as a plant person, as a tree person, and me as a gardener and tree person. The day that things switch and we start to see those rainy days, for me, it makes my life easier as far as watering. Also, it's just so much better for the trees.

I think that the trees are the last thing that get the water they need. If you're waiting for the rain and you're watering, you're trying to keep your garden going, but those trees need water too.

Michael: Yes, a lot of that stuff is just getting gobbled up on the surface from the lawn or the perennials or evaporation. Our sun's really intense out here,--

Michael: -so anything on the surface gets vaporized and barely gets into the tree roots. A good cleansing rain of half-inch to an inch of moisture hitting all at once is a total godsend to us out here.

Doug: The same here. Just make it a nice, slow rain.

Michael: Yes, no flooding or-- Yes.

Doug: Not a cloud burst where they won't soak in. The one thing you mentioned that is relatively new for me in doing this podcast is that compaction issue. Especially with construction, it's something that we never think about as a homeowner. I'm sure when you go to look at a tree and you see that they've just had heavy machinery going through there, that might be the first thing that comes to mind for you, right?

Michael: Yes. It's tough because it could be right as the house breaks ground, and they love a tree that they've built the house around. You just cringe because you know that the pain is coming, but in future years, they're going to feel like, oh, it's perfect. Everything's going well. House is looking great. Then the next time the tree leaves out the following year, it's sparse and leaves are small, and the tree is just telling you how bad it was the previous year when all the roots got cut out and trucks were driving all over it. It's really tough.

That's a challenge for construction when you're trying to get houses close to trees for shade and privacy and home value, but it's a tough mix between what trees want with that big, undisturbed root zone and what goes in for a house. It's a very challenging balance.

Doug: As we've already talked, there are ways to alleviate that compaction. Do you wait to look at the tree and see how it reacts to that compaction, or do you know sometimes right off the bat that that's going to need some work, that you should get in there right away with an air spade or whatever it is that you use, because you can see that giant machinery has been driving over there 150 times?

Michael: Yes, you can assume it right away. I think the rule of thumb is about 70% or 80% of the compaction happens on the first pass of a machine or foot traffic. So much of it immediately happens. That air space gets pushed out right away. The first truck goes around the property, and you can assume is already going to start to need some help, let alone all the other laps it's going to take or the other construction equipment.

I think right away you can start to look at, for one, how to minimize it or redirect traffic, but then if you've got an area that's been driven over, don't wait to see if it's got signs of problems. You can just jump right to it and start doing some of the air spade tricks and deep root fertilization and watering, and anything you can do to basically break up the soil is going to make a difference for the tree.

We had a client that built the house around a couple of big mature linden trees, and during the construction process, we did some air spading with radial trenching technique to bust up the compaction going away from the trunks outwards and made a difference. Right now, the home is fully built and landscaped, and those two trees are looking, I'd say, normal. They're not thriving through the whole process, but they definitely survived and are keepers 100%.

Doug: Let's go over exactly what air spading is because not everyone knows.

Michael: I'll put a little asterisk with our Colorado soils. It is a nightmare because we have really hard clay-compacted soils, and it's tough to break ground. It's a neat technique. We're using an air compressor to push air at a high speed into the ground to basically bust up the soil and actually blow it out of its place, and then backfill it with more light, less compacted material. It also just allows air to get into the root zones, where everywhere that the tree has run its roots, you're adding little channels of air so it can start to recuperate some of that air loss that it gets when all that soil gets smooshed out.

There's a few different techniques where you can do it with the air spading. Sometimes you're just trenching out from the center, out like a wheel in a spoke. Other times, you can probe into the ground in more of a grid pattern to try to just get a good spacing around the tree, underneath the canopy. Anything can help to just fluffing the soil, but it's not as easy as it sounds. [laughs]

Doug: How can we live so far away and have the same exact problems? We have the same exact soil. Certainly, it's not exact, but when you say that clay soil, that's the same thing we're dealing with here, clay and shale. Try and get an air spade through that. [laughs]

Michael: The ground can just feel unfazed by all that air pressure, and it's like you're blowing off a road instead.

Dough: I wanted to ask you about something else that you mentioned, which was the foot traffic. If it ends up a natural path over that tree, that could be an issue. I never thought of that.

Michael: Just anytime you get multiple passes of anything that's going over the soil, it's compressing it and taking that air space out, and it's making it harder for water to penetrate, too. I always like a good pathway where you can build something that's sturdy to walk on, but it will still maybe allow some water and air to get through it. I'm thinking of those pavers. It's a nice material to walk on, but then still water gets through them. It's almost like a mulch layer, but not quite. Just anything beats stepping on the bare soil, though.

Doug: That's a great idea. Then one more thing, lindens. What do you think of lindens? Is that a tree that you like, don't like, use, don't use?

Michael: I like lindens a lot. They have a really nice canopy shape. The flowers have a really nice fragrance. The fall color is simple and straightforward with them, but they're a good tree for us out here in Colorado. The Japanese beetles like to nibble on them a little bit, but it's not life or death to it. They're definitely on my guest list for Colorado trees.

Doug: Maybe you and I talked about it, but I mentioned it a couple of times. Whenever I hear lindens, I have a friend that worked at the local amusement park. They had a whole little grove of lindens. She said when they bloomed, it was too much for her, that was that fragrance. That just tells you, if you have one or two there, it'd be awesome.

Michael: Yes, one is plenty for the fragrance. I can imagine a whole grove is overwhelming.

Doug: It was for her. She'd work in different parts of the park when that would happen.

Michael: Yes, fair enough.

Doug: Whenever we look up into that tree and we see these changes in color early, is it always a negative?

Michael: I'd say generally yes, because it's going to be because water wasn't available in enough abundance, compaction was a factor, or it's just stressed from other insects or disease, or poor site conditions. You want to see trees go on a nice, gradual color schedule and be in sync with each other. That's just more tracking daylight length and temperatures dropping that make them change like they're supposed to. I think you'll also get your best colors that way.

When I see a lot of these early fall color trees, they're sporadic. You get some limbs are colors, some don't. Some don't even make the color change and just drop. They're also just not a very attractive color versus healthy trees, just put out vibrant, uniform, bright colors. That's just what you get with healthy trees. That's what we're always driving for.

Doug: Again, when we're talking about all these different things that it could be, that's why it's important that a certified arborist comes out and takes a look at it to be able to figure out exactly what the problem is, because there's a problem. [laughs]

Michael: It's usually more than one problem, too, at least maybe for us in Colorado, because we have tough growing conditions. It's not always as straightforward as it's just water. It's like, well, it's water, yes, but then there's also this compaction. It's making the water tough to get in. You've got damage on this trunk right here. That's affecting its uptake from the roots because part of its supply chain is just cut off because it got hit with a snowplow, or who knows what. It's a multi-problematic situation where you have that color change early.

Doug: I'm always interested in when I hear about you guys growing trees in that area because everyone says how difficult it is. Do you ever think about, "Boy, this job would be so much easier if I worked in Seattle?"

Michael: Oh, yes. Just the moisture we had this spring was like, well, this is all the trees need. [laughs] It felt too easy when we had the spring moisture that the trees were just happy on their own. Yes, we're basically just a high-altitude desert in Denver. We have all of the things that make trees growing in a desert a problem, and then we get actual winters. We can't just switch to cactus and palm trees and let the heat be the heat and the dryness be okay. We have to have stuff that survives cold winters and snow. We have a very weird growing zone. Until you get up in the mountains, then everything grows naturally. It's a little bit more on autopilot.

In the front range where Denver's situated, it's a nightmare for growing trees. Really, the only reason we have trees in the city is because irrigation is a thing. Otherwise, you'd only really have trees along our canals, and that would be it.

Doug: Is it mostly drip, or is it above ground, or is it both? Are there other things, too, that people are doing to keep the trees happy?

Michael: I'd say it's majority lawn irrigation is probably what's supporting majority of our trees. No, there's obviously xeriscape areas that they're running drips and minimal watering. Then you also have to have the right trees--

Michael: -that tolerate that, because the drip doesn't usually cover as much volume of water or as large of a square footage. Pretty much, you follow where there's green grass, and that's where people are having their most success with trees because they do get some of the moisture that keeps them alive.

Doug: Well, Michael, being an arborist in Denver, you deserve a gold star.

Michael: [laughs] I appreciate that. It feels like an uphill battle trying to keep people's trees happy here. Like you said,--

Doug: You're doing it.

Michael: -if only in Seattle, it'd be easy, maybe.

Doug: You're doing it.

Michael: Yes, we're doing the thing.

Doug: All right. Well, thanks again for your time. It was great to talk to you again, and I appreciate all the information. If you've got a tree out there, folks, that is turning color too early, get an arborist there, right?

Michael: Absolutely, yes. I appreciate you having me, and I would encourage anybody that can travel out here to Denver for our big fall color show is up in the mountains in September. We get all the aspens that pop out of all the natural conifers for it. If you can drive through the mountains around September, it's worth the price of admission.

Doug: All right, Michael. Thanks again.

Michael: Yes, thank you, Doug.

Doug: That was a nice conversation. I hope you enjoyed it too. I'm sure the arborists in Seattle would have something to say about the challenges that they have in their area. Now, tune in every Thursday to the Talking Trees podcast from the Davey Tree Expert Company. I'm your host, Doug Oster, and I need you to do me the same favor I ask you every week. Subscribe to the podcast if you haven't, so you'll never miss the show.

What should we be covering on this podcast? If you've got some ideas, there's a couple of different ways to reach us. You can send an email to podcasts@davey.com. That's P-O-D-C-A-S-T-S@D-A-V-E-Y.com. You can also click the link at the end of our show notes to send us a fan mail message. I promise you, your ideas could be on a future podcast. We'd love to hear from you. As always, we'd like to remind you on the Talking Trees podcast, you know it, trees are the answer.

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