Concrete Progress: Tending Nature

Concrete Progress is an ongoing series of columns by Peter Brewitt devoted to exploring America’s infrastructure. It is part of Orion’s two-year Reimagining Infrastructure project.

Seth Gillim hopes to put himself out of a job.

The assistant manager of Intervale Conservation Nursery, a tall Vermonter who fits his profession from his boots to his beard, spends his days raising neat rows of red maple and green ash saplings. But if he does his work well enough, he’ll have to find new plants to tend, for the nursery is on a mission: to restore river ecosystems and re-establish natural floodplains throughout and beyond the Lake Champlain watershed.

The Conservation Nursery is an arm of the Intervale Center, a nonprofit that works to strengthen community food systems, and I met Seth in their farmhouse/office north of Burlington. The thermometer read twenty-five below zero the morning I arrived in the Intervale, snow like dry ice on the rock-hard ground, and the rivers locked up from bank to bank. But in the nursery’s greenhouse I found cute little trees the length of my finger, patiently living out the winter in their yellow containers. Outside this arboreal neo-natal ward, their older relatives stood stark, red and brown and gray against the snow, with the kind of hard, dignified beauty of a Napoleonic regiment standing at attention. Some of them will only travel to the nearby Winooski River, but most of them will grow out in the wider world and remake rivers across Vermont. They are sorely needed.

Your town was probably founded on a river. They make up our natural infrastructure, with tiny trickles connecting the sea to far-off mountains; when it rains on Triple Divide Peak, in Montana, the water flows west to the Pacific Ocean, north to Hudson Bay, and south to the Gulf of Mexico. Rivers bind us together, but in 2014, most of them have been profoundly altered. We’ve straightened our rivers with levees, we’ve walled them up behind dams, we’ve run them through concrete tunnels, we’ve farmed, logged, paved right up to the mud line. There was a time when the heart of many cities was the riverfront, but we’ve become a nation of highways, and turned our waterways to gutters.

Natural rivers interact with their watersheds—they warm and cool, dry up and flood and meander. They spread seeds and silt downstream and fish upstream, and send both out across the floodplain. Over seasons and years, this movement defines a rich and diverse part of the natural landscape—the riparian zone. Our shackled rivers no longer do these things—we set their flows as if turning a dial and divert their water according to our demands, leaving dry and eroding banks. When our rivers do flood they find little or no natural floodplain, so the waters rush on to destroy whatever lies beyond. It also means that there is no buffer to absorb stormwater, effluent, or, especially, runoff from agriculture. Nitrogenous and phosphatic fertilizer seeps off of cropland and into rivers, feeding algal blooms and devouring oxygen. This sort of pollution is almost impossible to regulate using traditional methods—cornfields don’t have effluent pipes to improve and monitor.

These are nationwide—worldwide—problems, but they burst into Vermonters’ attention during 2011’s Tropical Storm Irene. Vermont’s swollen rivers inundated thousands of acres, costing the state hundreds of millions of dollars. The issue had been building, slowly, for years, but Irene turned awareness into alarm. The best way to defend against this sort of calamity and ensure resilience in the future, is to restore, to some extent, the natural floodplain. The state has begun to incentivize local governments to plant buffers, the Natural Resources Conservation Service (NRCS) funds erosion control nationwide, and gradually people have been planting 35-100 foot buffer zones all over Vermont. These restored floodplains not only absorb floods and pollution, they also provide important habitat for the many species that live between the river and the forest, from mink to bobolinks.

Red osier dogwoods await transplant in a winter field.

Of course, there is more to it than plopping trees into the ground. A poorly-planned buffer can end up as a weak scattering of invasive weeds. The Conservation Nursery takes a sophisticated approach, matching trees to rivers not just by species but by genotype. Many restoration projects get their trees from nurseries in other parts of the country, but this nursery grows Vermont trees for Vermont rivers. This may matter more than you’d think. You can get butternuts, Juglans cinerea, from anywhere, but given that the trees are usually only dispersed within their watersheds, by rodents or flooding, one valley’s butternuts can be quite different from another’s. The genotypic approach can be especially important for species threatened by disease—the nursery staff select trees that resist, say, butternut canker, strengthening the population by planting this stock.

The success of these trees depends upon the whole Burlington community. The nursery partners with an alphabet soup of conservation groups, from the NRCS to Green Mountain Coffee, but the nursery couldn’t run without volunteers. Amateur gardeners—school children, lawyers—plant, weed, and harvest the trees, providing more than 2,000 work-hours every year. That is like having another full-time gardener. The mission is also educational. The nursery has a strong relationship with the University of Vermont’s Rubenstein School of Environment and Natural Resources, and also hosts school groups. Tromping happily through the snow and silver maples, Seth showed me the nursery’s wayfaring signs, posted to educate the public about the tree species and natural processes that make the riparian zone work. Between volunteers, grants, donations, and sales, the conservation nursery is on solid economic footing, allowing it to concentrate on its trees.

Intervale’s is a bare root nursery, which means that most of its trees don’t come in pots or bags of soil; an alder, say, will only have its roots wrapped in wet sawdust before shipping out to a restoration project. It’s easier to transport bareroot trees as they’re essentially big sticks instead of potted plants, and the lack of soil means less chance of spreading invasive species, but the real and crucial advantage is cost. The nursery sells its trees for about $5 a stem; a tree in a container costs around $20. At the same time, they need to be planted with extra care, so restorationists must work a bit harder to ensure success. And they do: the industry standard for survival is 50 percent, but 75 percent of the 35,000 Intervale trees that went into the ground last year will grow into mature forest.

Seth is a long way from being out of a job. Many thousands of river-miles need restoration. But year by year, the Intervale Conservation Nursery’s trees are absorbing floods and pollution, sheltering wildlife, and shading the waterways that bind Vermont, and America, together.

Peter Brewitt has wondered about infrastructure ever since a flood kept him away from three days of kindergarten. He’s currently at work on a PhD at the University of California, Santa Cruz, where he’s researching the ways people restore and remake their environments. Photographs courtesy of Intervale Center.