Canterbury, NH – Over the years, Riverland has become overrun by invasive species. The crew at Riverland on the Merrimack made a start this summer to cut them back, mow them down, and otherwise begin a program of remediation and control. We are learning as we go. We decided to blog about it, because we figure other people can learn right along with us about what works and what doesn’t work.

To our knowledge, we have five, vegetative invasive species: Asian Bittersweet, Multi-Flora Rose, Autumn Olive, Buckthorn, and Poison Ivy. This is only what we know about. We could use the help of an expert to map out the true extent of the problem and to create a credible control plan.

We also know that these plants have a big head start on us. We can see them everywhere, of course, but that’s not very scientific. Fortunately, NH Fish and Game has documented the scale of the problem for us. Their website has a map of “Priority Areas for Invasive Plant Management” by town. From their website,  click on “Find Hotspots in your Community” and then, click on “Canterbury.”

Invasive plant management is a priority where ecologically important areas overlap with areas from which invasives are likely to spread. Riverland is a rare riverine habitat, prime farmland, and right on the river; invasives can easily spread downstream. To find Riverland on the map below, locate where the lower-left corner of the town line meets the river. Riverland is the property bordering the two, oxbow-shaped ponds.

Step 1: Mowing:

James Farquhar, bless him, does most of the mowing. He mowed the Riverland fields once in 2016, our first year here. The fields were a riot of golden rod and milkweed and had not been mowed in years. That’s him on our antique 1949 Ford 8N tractor in the photo below. Jon Hall of Gilmanton truly understands old tractors and is teaching us how to keep the old girl running. Fortunately, the bush hog is newer, because it is working really hard.

In 2017, James mowed the fields twice, and in some areas, three times. You can see in the 2017 photo that the mowing is beginning to bring back the grass and discourage the goldenrod/milkweed/ et. al. We estimate it will take another two summers of extensive mowing to bring the pastures back.

Step 2: Hacking back the jungle:

Autumn Olive and Asian Bittersweet are a bad combination. Bittersweet wants to climb and the autumn olive obliges by providing the scaffolding. These clusters of invasives can get to be two stories tall, and then climb over the top of nearby trees.

James, Jon, and son, Ben, spent two days hacking back the jungle shown in the photos below. As you can see from the photos, we found a truly beautiful Butternut tree in the center. The Butternut is a North American native which produces rich, butter-flavored nuts in late October, some years, when it feels like it, once it is 7-to-ten years old.

We figure other people may have an invasives problem also, so we are going to share how the crew brought this jungle down. This is just how we did it. We aren’t recommending any of these techniques per se. You will figure out your own path and take your own risks.

First, we got out the chainsaws and started hacking at the vines and anything else we could reach, wading deeper into the cluster as way opened. We kept a sharp eye out for trees we might want to keep and stuff falling from overhead. Slashing with a chainsaw in mid-air is dangerous, especially if you are standing on unstable slash. Some experience with a chainsaw is warranted.

Second, we got out the old garden rake and pulled the vines and pieces of branches out into the field as they rained down. You will see below why we raked. Then we cut some more autumn olive branches and bittersweet vines and raked some more until we could walk around the tree we discovered in the middle of the mess.

Third, we went to the back of the barn for our long-handled pruning tool and snipped the Bittersweet vines as high up as we could reach in the tree. Some of our vines were inches in diameter.

Fourth, Ben got a good hold on the now dangling bittersweet vines, and pulled. I mean, he really pulled. He had to be very careful that the branches did not break before the vines came down. We were not able to pull all of the vines out of the tree, so we left them there to turn brown and fall out in their own time. It was a good thing that the bittersweet had not yet set its berries, or they would have hung up there until some opportune moment to fall and reseed the bittersweet.

Fifth, you may wish to climb the tree in celebration, after the tree is free of smothering vines and undergrowth.

Sixth, we drove over the branches and vines and vegetation with our bush hog a few times to chop them up so they will compost in place. Bush hogs are amazing machines. Our Woods M5 can chop up branches up to about 3 inches in diameter. Stay way back. The shards fly like shrapnel.

It is probably best NOT to mow over branches when someone is sitting in the tree checking their messages.

Seventh, we celebrated our hard work in full recognition that we will have to keep mowing around this tree, probably forever, to keep that mess from growing back.

Step 3: Removing obstacles to mowing and climbing frames.

As you can see in the photos below, we had a decrepit shed crowned in bittersweet. Although it was pretty in the fall, it was just one more thing to mow around and something else the bittersweet could climb. Did I mention it was rotten and didn’t have a roof? It had to come down.

First, Jon and Ben pulled as many walls of the shed as they could wiggle free. Fortunately, the shed didn’t offer much resistance.

Second, when all else fails, try brute strength. Let’s see how much comes down if I really pull.

Third, when brute force is not enough, exert leverage on the corner that remains. This corner was entirely bound by bittersweet , which twined around the shed and the fence that ran nearby. The last bits of shed needed to be chopped free of the bittersweet before it could be entirely dismantled.

Fourth, James hauled most of the dismantled shed to the dump. The plywood walls showed signs of once having been covered in red paint. We didn’t know if that was lead paint and so, hauled it to the dump rather than burning it.

Step 4: Future work on invasives at Riverland…

The work of managing invasive species within the farm perimeter is going to take constant effort over many years. The autumn olive, mowed often enough, will probably eventually give up. And bittersweet with nothing to climb generally spreads across the ground, where it is a lot easier to mow…

However, it’s going to require endless mowing. We cut/mowed a large autumn olive bush out in the field in late June. The photo below shows how much it had grown back from the roots by late August.

This fall, we hope to continue to clear the plants climbing our barns, for the sake of the buildings. It is time-consuming to pull bittersweet off buildings, because the little tendrils need to be pulled off by hand. James has half cleared one barn.

We also hope to continue working on the autumn olive bushes that grow all over the river edge of the field. They need to be chopped down one-by-one. The photo below gives some idea of the scale of the problem.

Next year, we will continue the mowing, to maintain the progress we made this summer, and to start to clear and to take down the internal fences, which are too hole-y to keep livestock in or predators out . We will also continue clearing the inside of our perimeter fence, working toward the day when it can be replaced also.

Until then, peace….

Canterbury, NH (June 22, 2017) — The Feds showed up at Riverland today, hard on the heels of a small, green bug that is killing the ash trees in the wetland at the foot of our sandy bank, along the path to the beach. Theresa Murphy and Marci Murray, from the American Plant Health Inspection Service (APHIS), an arm of USDA, set out a new experiment designed to help slow the spread of this invasive beetle and to stem large expected losses to New Hampshire’s forestry industry.

Emerald ash borer (EAB), Agrilus planipennis Fairmaire, is an exotic beetle that was discovered in southeastern Michigan near Detroit and nearby areas of Ontario in 2002. The adult beetles nibble on ash foliage, but cause little damage. The larvae feed on the inner bark of ash trees, disrupting the tree’s ability to transport water and nutrients, which kills the tree.  The adult beetles nibble on ash foliage, but cause little damage. The larvae feed on the inner bark of ash trees, disrupting the tree’s ability to transport water and nutrients, which kills the tree.

EAB probably arrived in the United States on solid wood packing material carried in cargo ships or airplanes originating in its native Asia and has been working its way East. It was discovered in NH in Spring of 2013, in an ash tree along a city street in Concord. It’s not yet known to be in Maine or Rhode Island, but it’s in all states south and east of us and in Canadian provinces to the north. http://www.emeraldashborer.info.

Last summer, Bill Davidson of the New Hampshire Department of Resources and Economic Development (NHDRED) began work mapping the spread of the infection in New Hampshire and introducing parasitic wasps that eat the EAB larvae, with the hope that they will eventually slow the spread of the infection. When Bill arrived, he, had just finished his master’s degree in entomology, with a research focus on EAB. He explained that the wasps would not reproduce fast enough to stop our ash trees dying here at Riverland, but when the EAB had exhausted their food supply, the wasp would hopefully go with them when they colonized new stands of ash, and would slow their growth in the new location.

He released the wasps, otherwise known as biological controls, into the canopy of the ash trees, with the hope they would breed and find the EAB, their host. These wasps are tiny and cannot sting people and are thought to have no other impact on our habitat. He reported briefly this spring that he thought they had established themselves; he planned a second release this summer to reinforce this nascent population.

Theresa and Marci, who work with Juli Gould in the APHIS office in Buzzards Bay on Cape Cod, explained that they are experimenting with three kinds of wasps to see which are more effective in controlling EAB and just how they work. The three are tetrasticus, affectionately known as “tets,” Spathius, also known as “spats”, and oobius. Tets and spats infect the larvae and oobius infects the EAB eggs.

According to Theresa, each EAB can lay 100 eggs and that they must kill 99 percent of the larvae to get an infection under control. Those are tall odds, which is why they expect the infection to keep spreading for the foreseeable future.

They are setting out sticky yellow cards on small, medium, and large ash trees, at both the top and bottom of the trees, to see where the “tets” wasps fly in search of EAB larvae. In previous experiments in Michigan, the wasps have flown to the canopy of the trees; in New York, they did not. The team suspects that the wasps look for EAB larvae under thinner bark, say in saplings or in the new growth at the tops of the trees. They will also be looking to see whether the oobius wasps are killing the EAB eggs.

Today, they were shooting lines into the trees with a big sling shot to which they will rig the cards. Technicians from the University of New Hampshire will come weekly during the summer to set out clean sticky cards and take the old ones back to their lab for inspection. The New Hampshire Technical Institute (NHTI) will host a similar experiment. Theresa said Riverland and NHTI were chosen because they each had a moderate EAB infection, small, middle and large ash trees in close proximity to each other, and a landowner willing to give permission.

Signs of an EAB infection include “blonding” on the bark (a light-colored patch), often with woodpecker holes where the birds have drilled into the bark to eat the larvae. As the trees become stressed, the leaves in the canopy become patchy and the tree compensates by sprouting leaves straight from the trunk. For more on signs and symptoms of EAB, click here.

To report a suspected EAB infection in New Hampshire,click here.

Theresa said the EAB could devastate the ash population in New Hampshire. “I don’t want to lose more forest or species,” she said. “I want it to be here for the next generation of people.” If we learn more about the basic biology, we will know better about where and when to release biocontrols next time.

Ash comprises an estimated 6 percent of New Hampshire’s northern hardwood forests or about 25 million trees. It accounts for about 2.6 million board feet of the 223 million board feet of wood harvested annually in New Hampshire, according to Brad Simpkins, state forester. The ash species accounts for an estimated $500,000 paid annually in stumpage fees to New Hampshire landowners and $1.15 million annual to lumber mills. These figures are from a 2013 article found here.

According to a 2013 Eagle Tribune article, Karen Bennett, a UNH Cooperative Extension Forestry Specialist, said it could cost $25 million to replace the thousands of ash trees found along city streets. She further estimated that the loss of the ash population could cost $1 million per year to industries that use ash, typically in cabinetry and flooring. Firewood sellers could lose another $500,000 per year. Click here to learn more.

Experts say moving firewood from place to place is driving the rapid spread of this invasive species. The state has quarantined the movement of all ash trees, nursery stock, and hardwood firewood in Belknap, Hillsborough, Merrimack and Rockingham counties. For more information, go here.