If you’ve ever felt the impulse to hug a tree, your kinship is not unfounded. In the series “Cosmos: A Spacetime Odyssey,” the astrophysicist Neil DeGrasse Tyson proclaimed that trees are our distant cousins.
In Denver, most trees come from distant locales.
“This is a made-up environment. Trees and shrubs in Denver were brought from other places. This was antelope country, high plains desert,” said Chris Becker, a certified arborist and degreed urban forester with Schulhoff Tree & Lawn Care. He’s worked with Denver trees for 24 years.
Long before there were leafy neighborhoods in Denver, Native Americans revered trees they used for food, medicine and tools. The Cherokee called trees “the standing people.”
Rob Davis, Denver’s city forester for the past eight years, is one of the people standing up for approximately 80,000 park trees and 187,000 street trees in the City and County of Denver. Davis grew up in Greeley.
“We had a good-sized yard, and I free-climbed all the big trees. It was my introduction to my career — especially my connection to a sycamore in our yard, with its peeling bark and seed pods,” he said. “I’m in a downtown office most of the time now, but I’m fighting for a cause I believe in. Trees are part of the value of living in Colorado.”
Davis and his staff of 39 full-time employees concern themselves with Denver’s entire urban forest –an estimated 2.2 million trees with an asset value of $2.9 billion. According to the Denver Urban Forest fact sheet, trees shade 19.7 percent of the city. Trees stand as a valuable natural resource beautifying landscapes while cleaning the air, holding storm water, and providing shade from Colorado’s intense, high-altitude sun.
But Denver’s tree canopy faces a serious threat from emerald ash borers.
“They’re coming, and they will move through like fire. Treat your ash trees or plan to take them out,” Becker said of the devastating pest. “The bright side is with so much economic loss there’s funding for research and hope for advancements in treatments that will be more effective and cheaper.”
Davis said, “I would not be surprised to get a call today, and we can’t wait until we see the first green bug.”
To investigate the devastating pestap progression, he visited Chicago, Milwaukee and Madison, Wisconsin, “Itap sneaky and hard to find in early stages. Itap so invasive it goes from nothing to everywhere.”
The city’s “Be a Smart Ash” program prioritizes injecting ash trees with trunks 12 inches in circumference or larger. “These are high-quality street trees preventatively treated so we don’t have a big run on street trees,” he said.
“We know how important trees are. When people were surveyed for an outdoor downtown plan, the single favored basic amenity was trees. Not bathrooms or Wi-Fi or security, but trees,” he said. “People are passionate about trees, and tree preservation have been a hot topic for the past few years.”
Davis and Becker said development poses another threat to Denver’s urban forest.
“High-density development is good, but has a negative impact on the tree canopy. Impermeable surfaces and the loss of big trees affects water quality, environmental health, and temperatures,” Davis said. “Heat kills people.”
On the upside, Becker pointed out that development can add diversity to the tree canopy when new landscaping branches out into more species.
“We’re planting different and better trees, and a spectrum of varieties makes a healthier forest,” Becker said. “Smaller ornamental trees like Eastern redbuds turn heads. Landscapers are creating diversity with weeping trees, columnar evergreens, miniature fruit trees. Northern Red oaks have a decent growth rate and great fall color. We have more plant material for bees and birds and people who want to help wildlife.”
But Becker also noted a tree shortage. “In 2008, when the economy was down, nurseries cut back on trees so now certain sizes aren’t available.”
An often repeated aphorism holds that the best time to plant a tree was 20 years ago, and the second best time is now. For Davis and Becker, a frustration lies in the fact that the time investment for mature trees often goes undervalued.
“When people say I’ll give you two new trees for a 50-year-old tree, I say you give me your 50-year-old 401(k) plan, and I’ll give you two new ones,” Davis said. “No matter how much money or power people have, we can’t make 50-, 60-, 70-year-old trees that create a sense of place.”
Becker agreed. “In the big picture, there’s no replacing big trees,” he said. “People buy houses on more forested lots even though another property has vaulted ceilings and more stainless steel in the kitchen. They say ‘it reminds of the place I grew up’ or ‘that tree will have a great rope swing for the kids.’”
Overall, Denver’s tree canopy requires time, attention, and a bit of luck.
“We have our hands full here,” Davis said. “Itap a tough place to be a tree. We have to give our trees more respect here than other parts of country. In Indiana, if you clear a lot, it will eventually turn into a forest. But in Denver, every tree is an example of care from people for many years.”
