This may come off a little Lorax-like for you Seuss fans out there, but I speak for the trees (this week anyway). You may have noticed the stumps popping up around campus, marked with little groups of flags and a ring of sawdust. They’re scattered across campus, a few by Bucksbaum, one by Mac Field, a cluster behind Younker. These trees herald the arrival of the much-feared and seemingly unstoppable Emerald Ash Borer in our fair region.
The Emerald Ash Borer (EAB) is an aggressive beetle that targets ash tree species as its temporary home, where it lays its larvae, which eventually bore into the tree’s lifelines, cutting off the nutrient and water supply to the leafy-green canopy above and killing the tree.
The College preemptively cut down some of its ash trees this month as the EAB became an official resident of our neighboring Newton, a short jaunt away for the winged beetle. Because of the slow onset of the disease, which often takes up to three to four years to kill healthy ash trees, the trees become both hosts to the pest and falling hazards as the trees decay, making preemptive clearing a less-dangerous and less-costly precautionary management tactic.
So what? Another creepy, albeit iridescent, “bug.” They aren’t the obnoxious fruit flies perpetually roaming Noyce basement to taunt the studious, or the scary wolf spiders that prompt hallway squeals. Odds are, no EAB will ever ruin your Mac Field picnic, or fly up your nose during Frisbee practice.
But they will cost you a lot of money. About $1 billion a year in each of the 25 infected states, according to the U.S. Forest Service. In the grand scheme of government, this is but a small fraction—but Iowa’s $1 billion price tag is more than 70 percent of the College’s 2014 endowment. And it’s lost every year.
Invasive species are costing the U.S. big time, every year—more than $129 billion annually, according to the latest estimates by the Congressional Research Service. The chemicals, research and raw labor costs of removing and controlling invasive species are enormous, and they’re all self-inflicted. Every invasive species has a story of clumsy (or often thoughtless) humans behind it, whether it be the ballast waters of international tanker ships in Lake Michigan releasing the catastrophically successful zebra mussels, or the wooden shipping containers from China that likely carried the EAB to its newest home.
Of course, these stories are more understandable—the logistics of shipping in the globally-connected world we live in are full of complicated details that could lead to free-riding pests. There are worse cases. Sometimes humans deliberately insert a novel species to an environment, intending to remedy some system previously thrown out of balance by humans, and instead introducing a new ravenously destructive species to an already disturbed environment. The cane toad, introduced to Australia’s sugar cane fields in the 1930s as pest control, is the nightmarish embodiment of the latter scenario, costing the Australian government millions of dollars as it has grown from 102 toads introduced in 1934 to an estimated 200 million-plus today.
As long as humans are on the move, so are our uninvited pest species; we’re really rolling out the welcome wagon with our latest gift, climate change. Warmer winters and less predictable cold temperatures, as lovely as they may be for braving the northern winds on Mac, are not doing us any favors on the invasive species front. Cold snaps of extremely low temperatures have historically been crucial in deterring and stopping the onslaught of insect pests, native and invasive. Although this winter was a long and brutal one for the East Coast, these EABs are a hardy foe: only temperatures of -20° F will achieve significant reductions in the EAB populations. Horticulturists and ash-tree-lovers across the country are rooting for those wintry winds, and the steady march of climate change is certainly not improving the odds for the remaining eight billion ash trees out there today.
Not all hope is lost just yet. Insecticide treatments are available to inoculate ash trees, and both the College and the town have plans to treat dozens of ash trees starting as early as this summer. Although far from perfect, these insecticides are the best barrier available between the EAB and its future victims, and they save managers money and time. Without insecticides, authorities have to cope with enormous tree felling costs over a short period—it would take the EAB only about seven years to decimate the town’s 400-odd ash trees and swamp the City with tree-clearing costs.
Spending an average of $70 per tree every other year to inoculate our ash trees is a clear winning decision, both for the aesthetics of our campus and in the broader effort to curb the EAB’s spread. It may not keep the trees from falling to the EAB eventually, but at least it looks like the trees are well-spoken for in Grinnell.