The approach of fall in our region should mean a picturesque foliage display is also on the way, but more and more Kansas City trees are dying.
While it’s uncertain what that could mean for urban foliage photo shoots, fewer urban trees will mean a hotter city if the issue isn’t addressed.
“We are anecdotally seeing a lot of declines in our trees,” says Kansas City Parks Environmental Manager Stephen Van Rhein. “We’re doing a lot of removals … much more than we used to have historically.”
The question though, is why?
“I feel like it’s pretty clearly related to climate stress, but I hesitate to say for certain, because we don’t have really hard data on it,” Van Rhein says.
Van Rhein says it’s not as simple as less rain and more tree death. He says the area has experienced more rain, but the problem is that more of it is falling in shorter periods of time. This change is also coinciding with longer periods of drought.
“And that’s stressful for the trees here. So, the added stress will increase the likelihood of some other disease coming in or insects affecting it or just general decline for old age.”
Trees and urban life
It might sound bombastic, but urban trees can save lives. The World Economic Forum, citing a study in The Lancet, has reported that “increasing city tree cover to 30% … would prevent 2,644 premature deaths” in European cities.
And Kansas City itself is projected to get hotter — at least 4 degrees hotter by midcentury, and almost 8 degrees by 2100. These numbers and a lot of other data can be found in 2021’s KC Regional Climate Action Plan.
It’s safe to say that rising temperatures are already having an impact on the nation. The U.S. Department of Health and Human Services reports that heat deaths have risen steadily, and 2023 saw the most ever: 2302, up from 1722 in 2022.
The trend is not going unnoticed locally: as reported by KCUR, Kansas City and other cities have been participating in an NOAA effort to map urban heat islands — areas where temperatures can be 8 or more degrees hotter than in the rest of the city.
Van Rhein says the city’s forestry unit only oversees trees in the right of ways and on city property, but if removals are increasing in his area of responsibility, they’re increasing all over. And, removing a tree is not cheap.
“Our cost for tree removal varies depending on the tree and location up to $5000, sometimes more, Van Rhein says. “The average is about $2000.”
And, the city does not charge for this service, he notes.
Whether due to increased die-off or not, Kansas City has chosen to protect and restore its existing canopy. As for canopy protection, the city passed a “Tree Preservation and Protection” ordinance in 2023 requiring developers to protect a project site’s existing trees, plant new ones, or pay a fine.
And, some of the city’s hottest areas are leaning into canopy installation and preservation. The Crossroads Arts District is one such neighborhood, and its neighborhood association — with partners such as Evergy, Heartland Tree Alliance ReBuildKC — has planted over 180 new trees.
Zooming out, Kansas City has committed to planting 10,000 trees in three years, with this effort spurred by a $12 million U.S. Forest Service grant.
Why are the region’s urban trees dying?
Van Rhein notes that the city is at a critical juncture in its tree cover history.
“We planted a lot of trees when the city was being built” and as it’s expanded, he says, adding that now there are many “trees that are … between 50 to 80 years old at this point. We just don’t have a lot of trees in the 10 to 20-year or 30-year-old range.”
Van Rhein notes that increasing the stress on an older canopy means you’re just going to lose trees.
As for what specifically is killing the older trees, though, Van Rhein and other tree experts see climate change as but one piece of the complicated tree mortality puzzle, albeit an important one.
“There’s certainly a level of environmental stress, but we’re dealing with the urban canopy. We’re dealing with trees that were just planted outside their hardiness zone,” says Ryan Rastok, board certified master arborist and now owner of Lawrence Arborists.
Rastok came to entrepreneurship after working as a forest health coordinator with Kansas Forest Service.
“We do have some shifting in the climate … but it’s a little bit more nuanced,” Rastok says. “Really you’re dealing with stuff with just the wrong place, soil volume issues.”
And Rastok says urbanization itself can have a negative impact on existing canopies.
“So you have a large mature tree, and then they do a sidewalk expansion, and then cutting all the roots, and then several years later, those trees start to decline and die.”
Rastok does note emphatically, though, that sidewalk expansion is but a tiny source of tree stress, and sidewalks are essential infrastructure.
He also notes that newer pests, like the emerald ash borer, are impacting canopy health. But, surprisingly, where trees come from can also have an impact on future tree health.
“You can have issues that originate at the nursery,” he says. “Trees that have bad roots, circling, girdling roots, things like that, things that are kind of insidious and then take maybe 15, 20 years to cause trees to die.”
Rastok says this is a very common cause of latent tree mortality — how trees are managed at a nursery and then how they’re planted.
Planting, too, can be a little tricky, he notes.
If a tree is planted too deeply, the roots can suffocate or decay. There’s also the hardiness zone to consider. It’s common to see pines or spruces planted in this area, he says, and those can really struggle.
Interesting fact: Kansas’ only native evergreen is the Eastern redcedar. The Eastern redcedar is also native to Missouri, and so is the short-leaf pine.
But, even if you select a native species, regional provenance can throw a wrench in your plans.
“You could have a hackberry or something like that … that has really large native range throughout the whole continent, but if you get (it) from someplace in Georgia or the south (it) will languish quite a bit because the … genetics aren’t adapted to our climate,” Rastok says.
Urban trees face unique challenges
USGS Research Ecologist Dr. Peter Ibsen also is not willing to point to heat and climate change as the direct cause for urban tree mortality.
“Heat and drought are definitely strong drivers of canopy mortality and death,” he says, but it’s “tough to say within an urban environment because also it’s hard to be a tree in the big city.”
Ibsen says urban trees are challenged by “assaults from cars, from people, from pedestrians, from concrete, from pavement.”
And, Ibsen adds, urban soil itself can prove difficult for trees to succeed in. Past industrial use, soil compaction, too little nutrients — the list of challenges is long.
He does note that, if an area is not experiencing protracted drought and is an area that receives intermittent rain, the soil can in fact provide a fair amount of moisture because the concrete and pavement above reduce evaporation.
“But in general,” he says, “most city trees, unless you are in a very humid environment that gets regular rains, are going to need some sort of supplemental irrigation, some sort of supplemental assistance.”
How to plant for an uncertain future
So, what’s a city in need of trees to do?
“We decided that our best weapon against losing trees to climate change would be diversity overall, both with different species but also genetic diversity within that species,” Van Rhein says.
“So, we’re looking into choosing … genetic diversity from different areas, choosing (trees) grown southwest of us and then bringing them here. That’s probably our best model for trying to combat it.”
Van Rhein says the plan also includes planting more diversity along city blocks so that if one particular tree struggles, a block or area won’t lose a lot of trees at once.
The overall goal is to not have any more than 30% of any one family of tree planted in an area — more specifically, no more than 30% of any one family of trees, and no more than 20% of any one genus.
And, he says, given rising temperatures, the kinds of trees we see planted here will change.
“We are going to see a … shift in the types of trees that do well here. One of the ones that’s predicted to really move out of our area and move north and east of us is the walnut tree, particularly for our area.”
“We have a lot of walnut trees in Missouri … and it’s one … of the most sensitive to the changes we’re experiencing in terms of climate.”
As for what you can do to help a young tree succeed in this region, Ibsen recommends giving urban trees an extra head start. Start with a deeper planting well that is backfilled with nutrient-rich, quality soil.
Next, consider companion plantings around the tree — it prevents the soil from hardening off, Ibsen says.
Also, if you’re up for planting one tree, consider planting two. Or three. Ibsen says trees are able to share resources and effectively communicate with each other, increasing overall canopy resilience.
As for what to plant, Ibsen trusts local experts to get it right and urges locals to seek out quality nurseries that sell plants acclimated to this specific region.
“Talk to your local cooperative extension,” he says. “Talk to the people in your neighborhood that are planting trees. They know the best.”
This story was originally published by Flatland, a fellow member of the KC Media Collective.
