The arrival of emerald ash borer in Colorado has homeowners looking at all their trees with new appreciation.
Before-and-after photos of devastated neighborhoods in the Midwest — where ash trees are native and were an even larger part of the urban and suburban tree canopy — show just what’s at stake.
But the up side is that a larger conversation on trees is being opened up.
“There are a lot of nice ashes out there, and some are worth fighting to keep,” said Ralph Zentz, assistant city forester in Fort Collins. In fact, “some are gorgeous.”
Zentz knows how trees in parks, greenways and city centers define the character of a town, in addition to their impact on human health and the environment. Like many other city foresters along the Front Range, he’s been counting trees: He puts the total number of public trees in Fort Collins at 47,000, with an environmental value of $5.4 million per year.
Zentz has been an urban forester for years and has long known that trees provide quality-of-life benefits that can’t be put on a spreadsheet. But trees of all species also donate services that can be counted in dollars.
What’s a tree worth?
“A big value is the effect of shade on utility bills, but we can give a dollar amount of a tree’s worth in the pounds of pollutants pulled from the atmosphere, stormwater and flood mitigation, carbon sequestration, erosion control, urban wildlife habitat, or the (reduced) particulates in the air it filters” Zentz said.
There are tree-benefit calculators that allow foresters to plug in a tree’s size, canopy spread and other data and come up with an estimate on its worth. Estimates done by insurers rely on plant appraisals and are far more complicated. And neither accounts for the amount trees add to property values, but Zentz says well-kept trees help houses sell faster and for higher prices.
Keeping them healthy
The best thing to do to protect your tree investment is contacting a certified or consulting arborist to schedule a tree health assessment. Trees, like humans, need regular checkups.
“We look at both the biological tree — how it looks and functions — as well as the structural tree, which is how it holds itself together,” says Scott Grimes, owner of Colorado Tree Consultants and a consulting arborist who’s been working on trees for 33 years.
Tree experts’ visual inspections look for nutrition imbalances, insect or disease problems, weak points. what problems it has or what limits it. They’ll start with the view from ground level, noting potential risks like utility-lines or cracking sidewalks or foundations. Should concerns arise, they’ll climb the tree, gauging the scope of the problem and whether it needs correction. That could entail limb removal or an overall pruning — or treatment for pests or to correct nutrient deficiencies. The solution could be a simple as more (or less) water or beefing up mulch.
The benefit: “You catch problems early when a lot of options are available. Maybe there’s no need for pesticides, or you prevent tree or limb failure and potential lawsuits from damage,” Grimes said.
One of the most important times to do a tree health assessment is when you’re buying a new house — make it part of your home inspection. After all, the seller may not even know what kind of trees they have.
“The arborist can check for types of trees whose roots interfere with sewer lines, or find those trees that will need a substantial amount of work after you buy the property. Removals can cost thousands of dollars, so it’s good to know if the trees are going to need that before you buy the house,” he said.
Hiring a certified arborist, or one who is also a consulting one, is like choosing a doctor you can rely on. They’ll know what type of tree you have, which insects or problems it’s prone too, and how much the tree should grow each year.
To find a qualified arborist, check with the International Society of Arboriculture () or the American Society of Consulting Arborists () for lists of certified or consulting arborists in your area. Then ask for and check references.
After the initial checkup, plan on having your trees’ health assessed every few years, and whenever problems crop up. They’re an investment as much as your finances, and will reward regular care with a lifetime of service.
Signs your tree needs help
Here are some critical questions to decide whether your tree needs the help of a certified or consulting arborist.
• Do you know what kind of tree it is? Insect pests and diseases usually choose a narrow range of tree species to attack — for example, emerald ash borer only eats true ash, or Fraxinus species, and not mountain ash, which is in a different genus. And each tree species is usually prone to a certain range of cultural problems — for example, chlorosis — and likes a certain type of sun exposure and soil. So start with knowing which tree it is. If you don’t know that, get an expert to identify it for you while it has leaves on the branches.
• What is the problem? Are roots, trunk, bark, limbs, twigs or leaves being affected? Is there an insect, or signs (webs, exit holes in bark, sticky leaves, off-color ooze) of insect or disease damage? Is the damage in just one part of the tree, or all over? These are the kinds of questions you’ll get if you call or e-mail a Colorado State University Extension office and talk to one of the Master Gardener volunteers. It helps them greatly if you send photos of the problem with your e-mail.
• Is a major limb or the entire tree affected? Could it fall on a person, a fence, a roof, a vehicle or a power line? Get your tree expert there as soon as possible.
• Is the tree just not thriving overall, or thriving far too well, overgrowing its spot? The first can mean anything — once again, an arborist can help. The latter likely means the wrong tree was planted in the wrong place. Here, an arborist can remove the tree and suggest better choices for that location, considering soil, sun exposure, microclimate and the tree’s eventual size. He or she will also size up the needs of your home and family for shade, color and easy maintenance. — Susan Clotfelter, The Denver Post
