Caring for Durango’s urban forest, with nearly 12,000 trees, takes a lot of work. But it comes with rewards, including the chance to work with state-recognized specimens and the ability to curate parks with diverse species.

Planting and maintaining this system of low-density woodlands is more deliberate than one might think. But it ensures treescapes that improve the quality of life and that can be enjoyed for generations.

Sometimes, surprises lie in wait, such as when Matt Besecker, city arborist, learned of four chestnut trees growing at Escalante Middle School.

He didn’t think chestnut trees could be added to the city’s tree inventory, but now he is having second thoughts.

Besecker learned of the trees at Escalante about two weeks ago. He was surprised but thrilled after getting the chance to examine them.

He carried a couple chestnuts with him Thursday while showing off the trees at Escalante. He said he’d like to plant some of the chestnuts to see if they’ll take to the soil. And he is looking into how the Escalante chestnut trees came to be.

“There was a blight that came over from Japan in the early 1900s into New York City,” he said. “And then by the 1930s, this blight had wiped out all of our American chestnuts, or most of them – 99.9% of them.

“But (Escalante) school has either Chinese or European chestnuts,” he said. “I can’t tell the difference. But there’s four there, and they’re thriving.”

Besecker said he likes the idea of adding chestnut varieties to the city’s urban forest. But he still has a couple of problems to sort out.

Firstly, chestnuts have spiny hulls that could cause injury if stepped on, he said. So they don’t exactly make sense in the middle of a park’s grassy area. But they might work if placed along the edge of a park.

Secondly, the city avoids planting fruit-bearing trees because their produce can attract bears and deer. The city does plant crab apples and Krauter Vesuvius plum trees, but those have been bred not to produce fruit, he said.

“But we do like the flowering trees,” he said. “They provide a beautiful park setting. They’re great in parks.”

Besecker is trying to reintroduce another type of flowering tree, the redbud. There is one “huge” redbud alive and well on Ninth Street near the south City Market, so he knows they can live in Durango. He suspects the one on Ninth Street was planted in the 1930s.

When it comes to planning the city’s tree inventory, Besecker said it’s as simple as finding the right tree for the right location.

Do you want future shade for a park or do you want pretty flowering trees that contribute to a particular area’s aesthetic? Does a tree thrive well with little irrigation?

It doesn’t make sense to plant shade trees that will some day grow 60 feet tall under power lines. But power lines won’t ever be an issue for a 30-foot flowering tree, he said.

Besecker and his crew often lend expertise to Durango residents through a 50/50 cost-sharing program in which residents can plant a tree on their property in a city-owned public right of way. The city and the resident will split the cost of the tree itself, then the city will provide the labor to install the tree. The resident is responsible for watering it.

“Since they pay half for the tree, I try to work with them to help them pick out a species that they might want,” he said. “It’s a great program. We’ve had the program for at least 20 years now.”

The city also works with a contractor through its 2014 forest management plan to plant trees in its parks. Besecker works with the contractor on where, what and how many trees to plant.

For example, 29 trees were planted this spring along East Third Avenue, he said. The trees, a variety of species, are about 10 years old and were obtained from a nursery. Most of them have trunks about 2 inches in diameter and all are shade trees – they will grow large and produce canopies that offer shade to the ground below.

Ture Nycum, Durango Parks and Recreation director, said East Third Avenue is unique in that it is a “monoculture” – existing adult trees are all the same species, American elm. He said part of the effort to plant new trees there is to diversify the available species.

Diversification is important because it protects the overall tree population from disease. If a disease happens to infect one species in the area, other trees that are immune to the disease will continue to prosper, Nycum said.

“The Dutch elm disease (a fungus) wiped out a lot of trees in the East – American elms,” he said. “But apparently it didn’t come here because we still have a lot of American elms in Durango.”

He said many of the elms planted on East Third Avenue have probably been there since the 1890s.

Soil diversity is also important. Soil in Southwest Colorado isn’t of the best quality compared to the lowlands of the Midwest where the ground is fertile, he said.

The city has successfully planted and grown trees of a Midwest origin, he said. They appear to have adapted to the local soil. But in general, it is difficult to grow trees in Durango.

Water availability is another factor always under consideration. Certain species are adapted to drought more than others, he said.

While planning for tree growth is important, maintenance is a huge part of keeping Durango’s urban forest healthy and thriving.

Besecker said his crew consists of only three or four workers, including himself, and there is always a tree that needs to be removed somewhere. Sometimes, the tree is sick or dead. Sometimes, it is an invasive species, such as the Siberian elm tree that grows rampantly in Durango.

Nycum said Durango’s trees are an important part of the community.

“The trees that we have in this community are valued and people support the tree program very much,” he said. “... It’s nice to have that community support and to have the vibrant urban forest that we have. It does take a lot of work.”

The Colorado Tree Coalition, a nonprofit administered by the Colorado State Forest Service that supports community forestry services, recognized a Rio Grande cottonwood tree on 17th Street as a state championship tree for its age and size. The tree towers above others at over 100 feet tall. The trunk’s diameter at breast height is 8 feet around and the tree is likely over 100 years old, he said.

The city’s oldest tree, a ponderosa pine along the Animas River Trail, is about twice as old as the Rio Grande cottonwood.

Besecker said if anyone knows of a tree older than the approximately 200-year-old ponderosa pine, he would like to hear from them. He is passionate about learning more about Durango’s tree population.

cburney@durangoherald.com