Confronting the threat of the Emerald ash borer
March 7, 2017 – EAB workshop
My husband Bill and I attended a workshop on Emerald ash borer (EAB) on the campus of the University of Wisconsin Superior. A sunny, blustery day with 50-miles-per-hour winds; the presenters had to yell just so the nine of us gathered around them could hear. They had chosen this spot because we could walk from the parking lot to a beetle-infested white ash, where woodpeckers were feeding on the beetle larvae so aggressively, they had torn small strips of bark from the tree. Jennifer Burington, a Plant Health Specialist with the Minnesota Department of Agriculture, and Jon Oshthus, EAB Biocontrol Coordinator, explained their “community preparation” project. The basic idea is that the more eyes there are out there looking for EAB, the better chance we have to manage them. Not eradicate, manage.
This incredibly destructive pest is native to eastern Asia and probably arrived in the Midwest in packing crates or pallets. It was first discovered in Detroit in 2002, and since then it has steadily spread across the eastern U.S., killing hundreds of millions of trees. Minnesota has the highest volume of ash trees in the nation, with almost a billion trees planted along city streets and growing vigorously in woodlands like ours.
The adult beetle is metallic green and about a half-inch long. First discovered in Minnesota in 2009, it arrived in Duluth in 2016, on Park Point, the long spit of sandy land that protects the Duluth harbor. Our home is about ten miles away from the Point. When the beetle gets to our 80-acre place, where hundreds of fifty-year-old ash trees grow in low, wet parts of the woods, what will happen? If all the ash trees die, as has been happening wherever the beetle strikes, what will become of the other plants and animals that currently make their homes here? The whole ecosystem could change and we could end up with nothing but cattails and shrubs.
One encouraging fact: Jennifer says that given how long EAB has been in Minnesota, it has infested fewer counties than expected based on other states’ experience. She credits aggressive action by cities, cold weather, and lots of eyes looking. Cold temperatures can knock them back temporarily. The polar vortex of 2014 set Minnesota’s EAB population back by about a year, Jennifer says.
The beetles lay eggs in serpentine galleries just below the bark of mature trees. The larvae spend one or two years in these meandering homes, which cut off the tree’s supply of nutrients. When they emerge as adults, the beetles can fly as far as five miles, but typically they stay much closer, starting the cycle again. In a typical pattern, we might see some adult beetles in the second year of infestation, woodpecker damage and bark splitting on affected trees in the third year, thinning of the canopy in the fourth year, and dead trees in year five.
The Minnesota Department of Agriculture tries to hold the pest in check by releasing three types of parasitoid wasps in places where EAB is discovered. These wasps were brought in from Asia and are bred in a special lab in Michigan. When they’re set free to dine on beetle larvae, they manage to reproduce and move through the woods along with the beetles. Last year one of today’s presenters, John Osthus, visited our woods and asked us to keep an eye out for the woodpecker holes that might indicate the presence of EAB. The wasps can’t be released until the beetles arrive, because the beetle larvae are the only thing the wasps will eat.
March 13 – Ordering trees
Concern about EAB is prompting us to move ahead with part of our forest stewardship plan, which was drawn up several years ago by forester Matt Tyler of Nadarra Forestry. The plan provides lots of information about the trees growing here and what we should do to keep them healthy. It warns of the risk posed by the Emerald ash borer in the low, swampy part of our woods that’s dominated by black ash. The plan includes information about the federal Agriculture Department’s Natural Resources Conservation Service (NRCS). This agency helps farmers and other landowners with “financial and technical assistance to eligible producers to conserve and enhance soil, water, air, and related natural resources on their land.” Back in 2014, we signed an agreement with the local NRCS office that specifies what we will do and how the agency will reimburse us for our expenses. Basically, the plan is to cut some of the mature ash in a 2.7-acre area to make way for new plantings, plant 680 seedlings of several species, and protect them from deer and weeds. We were allowed nearly six-thousand dollars to do this. Recommended species include white and black spruce, tamarack, red maple, and river birch. Bill and I decided we’d also plant a few white pines because they are such a special tree.
I was planning to get the trees from the South St. Louis County Soil and Water Conservation Service, where we’ve bought a few trees before. But they didn’t have enough of some species, so we ordered some from the Itasca Greenhouse in Cohasset, up on the western end of the Iron Range.
Now, before the trees arrive, I’m learning about how to plant these little seedlings and the best ways to protect them from deer and snowshoe hares. Based on previous experience, we know that deer tend to leave spruce alone, but in years when there are lots of deer and not enough food, they’ll eat anything. Looking online and talking with local experts, I learn that some people swear by spray repellent (a concoction of stinky stuff like rotten eggs, garlic, blood, fish oil–you name it–designed to stay on the branches through a given number of rains). But our contract with NRCS calls for plastic tubes for the deciduous trees. Some people worry the tubes might concentrate heat and moisture which could lead to disease. But the tubes I’m ordering have ventilation holes and according to the sales blurb, “provide an improved micro-climate at the base of the shelter which results in better initial establishment of the tree,” and “a ventilated upper section… which enables the plant to acclimatise to external conditions improving trunk and root development.” Note the British spelling of “acclimatize.” These tubes come from England!
I’m ordering 5-foot tubes, about four inches in diameter. It’s hard to picture how a tree can grow leaves, feed itself, and thrive for several years in such a constricted environment, but apparently this is how we do things now.
The NRCS contract also calls for weed-control mats. These are 3×3-foot squares of black plastic, pinned to the ground with a staple on each corner. A slit in the middle allows the tree to poke through.
All of these precautions should help us meet the terms of the contract, which calls for us to maintain a 75-percent survival rate for these seedlings after five years. I have no idea whether we’ll be able to accomplish this! Do these products work? Will the deer be extra-hungry and eat the spruce? Will we get enough rain to keep the trees alive? So much is completely beyond our control! I guess we’ll hitch up our pants and do the best we can.
March 15 – Preparing the site
We just hauled four 12” diameter ash logs up to the house from the planting site. The NRCS contract calls for “forest stand improvement” to prepare for “tree/shrub establishment.” Basically that means cutting some mature trees to provide more sun for the new ones. We’ll use these logs for firewood next winter; black ash is terrific firewood–it splits easily and burns long and hot. Our original plan was to sell some logs for lumber. Black ash is like oak on steroids, with dark coloring and dramatic grain; it can be spectacular in paneling, cabinetry, and furniture. Using the wood that way would continue to prevent its carbon from entering the atmosphere, and we would have been happy to take a small step in mitigating global warming. But for two winters in a row it was too warm to freeze the ground, and that meant a logger we’d used before, Jacob Obletz and his trusty team of draft horses, Daisy and Diamond, couldn’t work in the woods.
Meanwhile, last July a storm with hurricane-force winds knocked down dozens of trees all over our land, including in the planting site. So we just cut the few trees that had been marked by the NRCS for removal that weren’t downed by the storm, and hauled as many to the house for firewood as we could manage.
March 16 – Protection supplies
We have our list of needed supplies to protect the trees, so I checked with Lowrie Tucker at Conservation Services in Waynesboro, Virginia. That’s near where I spent a summer after college, living in a lean-to on the edge of the George Washington National Forest. As we talked, I found out that Lowrie had his own experiences of Minnesota wind events to share.
He told me he’d been in Minnesota years ago, part of a fire crew in the Superior National Forest outside Ely. They were doing spring maintenance to prepare for the fire season, in the area that had been wiped out by the 1999 straight-line wind blowdown. What an experience! “There were logs everywhere,” he remembered, “You’d be working along and every now and then somebody would just disappear!” The downed trees were lying in dense tangles, sometimes five deep. His time in northern Minnesota also gave Lowrie a thorough appreciation for mosquitoes.
When I asked if the supplies we need can be here by mid-May, he was taken aback. “I was going to ship them tomorrow,” he said. “Well, the trees aren’t coming until mid-May,” I answered. “Oh, that’s right,” he realized: “you still have snow on the ground. Our tulips and forsythia are blooming.” I replied that I wasn’t interested in hearing about that.
Bill and I decide to go ahead with the order: Conservation Services has everything we need, and the prices are good, even considering that the shipping is going to be really expensive. Also, it’s coming on a semi-truck, and we’ll need a forklift to unload it. I called our friend with a skid loader and he was delighted to promise to help–but he’s a snowbird and won’t promise when he’ll be back. So the Fed Ex semi-truck driver will need to have a lift gate to unload the pallet onto our driveway.
March 30 – Getting help with planting
At the suggestion of the NRCS staff, today I talked with Bob Slater at the Minnesota DNR. Bob is Assistant Area Forestry Supervisor in northeastern Minnesota, and his job involves getting hundreds of thousands of trees planted on state land each spring. He hires a crew that travels around the country. He told me there are sometimes days when his trees have not arrived or a planting site is not ready, and the crew could come to our place and whip our few hundred trees into the ground in half a day. Sounds good to me! I called the contractor, Rick Thomas at Express Forestry Service in Arkansas, who gave me a quote of $600 for the job.
April 13 – The protection supplies arrive
We got the supplies today. The Fed Ex truck was unable to deliver to our house because the spring road restrictions are on, and a semi would definitely weigh too much for our gravel road. So we rented a pick-up to get them from the Fed Ex warehouse.
The load was on a pallet, with several layers of oak stakes at the bottom, three heavy cardboard boxes filled with staples, a layer of plastic mats, all topped off with several big bundles of pale green tubes. It’s a bit like a giant sandwich, all wrapped in plastic.
Bill and I hauled some tubes and three bundles of stakes – 25 to the bundle — out to the site today. Very frustrating. One of our sleds is shorter than the stakes. When we went downhill, the stakes fell forward and dug into the ground. When we went uphill, they slid off the back. The other sled is a kid’s snow sled and has a corner cracked off, which makes it travel lopsidedly, the load threatening to fall off during the entire trip. When we started this process, no one told us how much work it would be. And we’re not even planting the trees!
May 2 – Picking up trees
At least, we hope we won’t have to plant all 680 trees! There has been so much up in the air in the last couple of weeks, I hesitate to predict how everything will turn out. At first we thought the crew would be here in mid-April; then bad weather prevented the state nurseries from lifting their seedlings out of the ground and shipping them, so everything was postponed at least a week. Today Bob Slater from the DNR called to say the crew will be here Thursday, and he won’t have all his seedlings yet, so he wants the crew to start here at our place. Luckily, we just picked up the bulk of our seedlings today.
We drove about two hours to Itasca Greenhouse in Cohasset, just west of Grand Rapids. We were welcomed by Krista Roettger, a friendly, enthusiastic manager-in-training. This place has two greenhouses alongside four unheated tunnels, and typically grows three million trees each year. They supply “containerized” seedlings to forestry departments, Christmas tree farms, and retail nurseries. The trees cost a little less than a dollar apiece, and the cost will be reimbursed by the NRCS.
Krista gave us a tour and explained that her trees grow in the greenhouse for the first year of their lives, nestled in hefty Styrofoam blocks that are perforated with dozens of slots the size of a thick finger. The seedlings then spend one season outside to get used to real weather. Then workers pull them out of the Styrofoam blocks and bundle them in bunches of 20 or 25, wrap the soil-packed roots in plastic, and pack them in cardboard boxes. These are placed in giant refrigerators until it’s time to send them off for planting.
We were interested to learn that the greenhouses are heated with water piped from the nearby Minnesota Power generating station. The power plant uses water to cool the steam from the turbines; that same water warms the greenhouses and then returns to the power plant to cool the steam again. Very efficient!
May 4 – Guatemalan crew plants trees
I am exhausted and out of breath. I’ve just watched 14 young men from Guatemala plant 550 little trees in less than three hours. It was a treat to be in our woods, normally quiet except for a little bird song, watching so much activity and hearing jokes and laughter.
This crew had just arrived in Minnesota from the state of Virginia. Later today they’ll start on a job for the Minnesota DNR, planting 150,000 trees in four or five days. They travel together in a van, towing a trailer with their gear, staying in cheap motels. When the planting season is done here, they return to Guatemala where they plant corn and other crops. Their work here is done under a federal permit.
We had 125 each of white spruce, black spruce, and tamarack, and 150 river birch. For each of these trees, less than a foot tall and just a single stem, a man scraped vegetation from the soil surface with a machete, plunged a flat shovel into the soft earth, dropped the tree, complete with its plug of soil, into the narrow opening, pressed the soil around it, and then lowered a black plastic mat with a slit in the center over the tree, stapling the plastic into the ground at each corner. For the river birch, they carefully slid a five-foot plastic tube over each tree, pressed it two inches or so into the soil, threaded a wooden stake through two plastic zip ties in the tube, pounded the stake a foot into the ground, and tightened the zip ties. Finally, they pulled a mesh sock over the top of the tube to prevent birds from getting caught inside.
The crew didn’t seem to be very familiar with these tubes, but we studied the instruction sheet together and they picked up the techniques right away. “Staple” is a word I didn’t know in Spanish, but I learned: “grapa.” I always enjoy a chance to practice my Spanish, and the crew leader and the rest graciously tolerated my mistakes.
The planting area was a terrible mess, with trees hit by last July’s windstorm lying on the ground like a tangle of giant matchsticks; the ground was wet and uneven, and there was plenty of undergrowth. I felt badly that they had to do this work in such an uncooperative setting, but they worked cheerfully enough, and very carefully.
This was the event we had been working toward for so many months. Last night it seemed unreal, like it could never really happen. But today it seemed pretty normal. It was amazing to see how quickly those little trees could get in the ground, and now our planting area is a thicket of five-foot plastic tubes.
May 13 – Round two of planting, this time on our own
If only we’d had the help of the crew from Guatemala today instead of last week! Yesterday I picked up the trees we had ordered from the South St. Louis County Soil & Water Conservation District: 150 red maples and 25 white pines. We tucked them in the root cellar, with wet burlap and plastic wrapped around the roots.
This morning we marched into the woods for our first foray at planting these trees ourselves. We were out there for two hours and only planted 20 trees; I was hoping for twice that much. At this rate, it’s going to take us a good ten days to get these trees in the ground, and by then the bug season could be well underway, making the job ten times as unpleasant.
Our routine went like this: Bill scouted out likely places to plant and stuck the shovel in the ground, searching for spots without big rocks or roots to stop the shovel. When he found such a place, I slid the roots in beside the shovel, and as he pulled the shovel out I pushed the roots deeper into the hole. Then came the familiar placement of plastic mat, staples, plastic tube, wooden stake, and mesh bag. It’s a lot easier to watch someone else do all this than to do it yourself! We’re fighting underbrush, wet and uneven ground everywhere. My feet are sore, my back is sore, my hands are sore. I think of the crew, who do this work day after day.
On the way back to the house we noticed that the woods close to the house are carpeted in a thick mat of lily-of-the-valley. They must have seeded themselves from plants we’ve had in the garden. I recently learned these are considered invasive, and they certainly seemed so around our house. The whole experience made me feel depressed about the destructive impacts of people, including ourselves. People brought the Emerald ash borer which will kill the ash, necessitating our blundering planting efforts. Meanwhile we and others are spreading lily-of-the-valley and buckthorn and honeysuckle and countless other invasive plants. It’s very discouraging.
May 22 – Our last day of planting
Gradually we learned better techniques for getting the trees in the ground, and we developed a relatively efficient routine. We spent two hours each day for eight days, getting wet, muddy and very tired. But at last we’ve put all the trees in the ground, and we have an appointment for the NRCS person to come out and inspect our work. We don’t know exactly what that will mean, but we’re hoping we’ll pass! We still need to haul 25 cages out there to protect the white pines from the deer.
June 2 – NRCS inspection
Gail Bong is a Soil Conservation Technician at NRCS, a youthful grandmother, and a willing explainer of federal rules and living systems. She looked at our thicket of tubes and our evergreens on their mats and pronounced it good. She said these young trees probably have enough light – if only the ferns don’t overwhelm them in the first year or two. She said it was a good idea to leave quite a few of the mature ash because of the tremendous amount of water the big trees suck out of the wet soil. If there were no trees here to draw out the moisture, the waterlogged soil could drown out other living things – ferns, raspberries, bunchberries, etc. Also, the big trees keep the understory shaded and add leaf litter to enrich the soil. We noticed several little white pines had turned brown already, and Gail showed us how to figure out whether they were planted too deep or too shallow. She suggested we buy 25 spruce trees each year to replace the inevitable losses. Although she’s never seen deer browse on tamaracks, when we told her that a neighbor and tree expert, Tim Rutka, recommended using smelly spray to protect them, she gracefully deferred to his expertise.
June 10 – Last day of caging
Carrying the fencing out to the site turned out to be the hardest part of protecting the white pines from deer. We bought two rolls of five-foot-tall stock fencing at a local feed store. It was a bit more expensive than it would have been at the big box store, but it was a lot closer and a lot more pleasant. To get the rolls out there, we slid a long plumbing pipe through the center of the roll and each of us took one end of the pipe, the fencing slung between us. It was heavy! Once out there, we cut the fencing into eight-foot sections, fastened the cut ends together to form a two-and-a-half-foot-diameter cage, and set one over each of the white pines. We staked them and then marked the cages with orange tape so they’ll be easy to find. We’ll need to inspect the trees at least yearly. If they don’t die right away, we’ll trim the lower branches to try to prevent infection with white pine blister rust, a deadly disease caused by a fungus, Cronartium ribicola, which is common in northeastern Minnesota. Another non-native, this fungus cycles between its alternate hosts, white pines and currant or gooseberry bushes. It can kill even a sturdy six-foot tree. It would be heartbreaking to invest this much effort, watch a tree grow for years, and then lose it. But that may happen.
June 22 – Waiting for fall
Summer is here, and with it the bugs, which normally discourage any warm-weather forays into our woods. We have plenty to do in the yard and garden, anyway. But this year we’ll be happy to take any interested visitors out to see our planting site to check on our little ones. In the fall we’ll spray the tamaracks with something smelly, and in the winter we’ll keep an eye out for the woodpecker holes that may indicate the EAB has arrived. We’ll also smile as we trek through our planting area on snowshoes. This business of planting trees involves hard work and worry, but also some satisfaction and anticipation of growth and diversity in our woods.