Seeing the forest for the trees
NDSU professor dedicates career to introducing woody plants to the Northern Plains
Ask Dale Herman to pick his favorite tree, and he looks like he's been asked to choose a favorite child.
Admittedly, it's no easy question for a plant scientist who has dedicated his life to the study of trees.
But after some nervous grinning and throat clearing, Herman settles on a pet cultivar: Herman Prairie Statesman, a tree fine enough to carry his name.
The Swiss Stone Pine was planted at a test site near Absaraka, where it grew into a tall, elegant specimen with dense, emerald-hued needles. The pine won't be available to the tree-buying public until at least 2007. Some of Herman's connections in the wholesale nursery trade wanted him to cut down the tree so thousands of propagation samples could be collected to start a whole new fleet of baby Statesmen. But Herman and his colleagues couldn't stand the thought of sacrificing such a remarkable tree. And so they decided to cut far fewer propagation samples from the elder Statesman, saving it in the process. The pine remains, standing like a stately aristocrat among the other trees in the research arboretum.
Sometimes, you just have to wait for a good thing.
Nobody understands this better than Herman, a professor in plant sciences. He has spent 33 years selecting, planting, evaluating and introducing new varieties of trees and shrubs in the Northern Plains.
It's a job that might have stopped Johnny Appleseed in his bare-footed tracks. The region's temperamental climate, drought concerns and diverse soil and pH conditions do not a forest make.
Consequently, the state's native species of large trees -- such as cottonwood, green ash and box-elder -- can be counted on two hands.
Yet any plant scientist worth his microscope knows diversification is as important to nature as it is to farming or stock portfolios.
Herman's fear is in developing a "monoculture," a high population of just a few different species. Such homogeneity spells disaster if a pest or disease strikes.
To illustrate, Herman points to Dutch elm disease. At one time, 75 percent of the trees planted on many cities' boulevards were elms. When the disease hit, it spread easily from tree to tree. As a result, many city officials remain wary of planting replacement elms.
He is optimistic -- in the cautious way that scientists are optimistic -- about one of his proposed introductions: an American elm that shows promising disease resistance. But then again, he's excited about all 30 of the introductions he's trademarked since 1986. Like the hybrid oak he hopes will be propagated someday, or the maples that would add some highly coveted reds and oranges to the region's fall palette. It could take years for Herman to fully study and foster these varieties, but he hopes when his career winds down, his students will take up the spade.
If his career ever winds down. One gets the feeling that Herman, a trim and vigorous 66, is as enthused about his work today as he was as a farm boy growing up on the treeless Plains.
North-central North Dakota was different back then, before the heavier precipitation of recent years filled lakes and caused trees to sprout on the prairies.
In the '30s, '40s and '50s, the rolling terrain around tiny Brinsmade, N.D., was dry, sandy and bare. But Dale's parents, George and Elsie Herman, needed to feed their growing brood, so they devoted a whole acre to their vegetable garden.
They had a way with it, too. Tomatoes fattened on the vine; cucumbers thrived; pea pods grew plump and sweet. Some years, Elsie canned up to a thousand quarts of produce.
During the grittiest years of the Depression, George supplemented the family income by planting potatoes, muskmelon, watermelon and pumpkins in the dried-up lake bottom, then selling his produce door-to-door.
Only one type of plant defied the greenest of Herman thumbs. Dale, the youngest of the nine children, watched for years as his family and their neighbors planted saplings in the area's light, gravelly soil. Again and again, the fragile trees died.
Young Dale's resolve took root. Someday, he decided, he would find varieties of trees that could survive throughout the state.
"It presents a challenge," Herman says. "You want to prove nature wrong." Fortunately, the state's land-grant university offered a robust horticulture program. After graduating from NDSU with his bachelor's in 1960, Herman was accepted into Purdue University, where he earned his master's and doctoral degrees in horticulture.
He returned to his alma mater in 1971 after spending five years on the faculty at South Dakota State University. Almost immediately, he committed himself to the greening of the Plains.
Or, as his life's work is more formally titled, the "Selection, Evaluation and Introduction of Hardy Superior Woody Plants for the Northern Plains." After 15 years of hard work, Herman introduced his first woody plant: the Meadowlark Forsythia, a sturdy ornamental shrub that produces a flurry of bright yellow flowers. Since then, he has introduced new woody plants at a dependable rate of one or two new varieties a year.
Much has changed since Herman's earliest years in horticulture. The inventory of plant varieties has exploded, partly because scientists now covet plant diversity. "They, including nursery men, used to go down the rows and rogue out anything that looked odd or different," Herman says. "Now, if they find a plant that is different from the norm, they guard it." Interest in landscaping plants has surged as well. The nursery trade views the shift from practical to aesthetic gardening as evidence of a maturing society.
Half a century ago, Americans tended gardens for the same reason the Hermans did: They needed the food. "Landscaping was a lilac bush and maybe a box-elder tree," Herman says.
Today, homeowners tend to view gardening as the meringue on the pie. They watch HGTV, know about the latest perennials and spend thousands of dollars on elaborately staged landscaping.
Northern Plains dwellers are just as interested in aesthetic plants, but they also want durability. The ideal plant must have thick, glossy leaves that also resist pests. It should produce fruits and flowers that are exuberant, but not messy. And it needs to possess both vibrant fall foliage and a tolerance for extreme weather conditions.
As more people become urban dwellers, they also need to downsize their plants. A mighty oak may be magnificent, but it doesn't leave much room for the kids' swing set.
So Herman also introduces compact trees and shrubs that tuck neatly into small backyards.
Verona Prairie Radiance exemplifies all he has worked to achieve. The rugged winterberry tree produces fall foliage that changes according to its soil - red leaves in sandy loam, intense pink in the heavy, black clay of the Red River Valley. In late September, its display of delicate pink capsules split to expose bright red seeds.
Other popular introductions include Herman's trio of birches, which provide the white-as-sugar bark that homeowners covet for landscape appeal. Before Herman's work, few birches naturally fit the area's climate and soil.
Now there's Varen Prairie Dream, a paper birch with a snow-white bark that peels away in artful layers year-round, creating extra visual interest; VerDale Prairie Vision, an Asian white birch with white bark and blackish markings; and Fargo Dakota Pinnacle, an Asian birch with creamy bark.
The birches aren't just showy; they're tough. Bronze birch borers threaten to do to white birches what Dutch elm disease did to elms. The borers' larvae tunnel beneath the bark, causing the trunk to girdle and the tree to die. But after 25 years of study, Varen and VerDale have both defied the pest.
The original wood samples for Herman's trees come from sources near and far. His Prairie Expedition American elm was a lone survivor found among diseased elms along the Wild Rice River. Varen sprouted up from a seed source in the Killdeer Mountains, the Fargo cultivar from a multi-species birch seedling population, and VerDale from an Asian white birch native to western China.
In fact, some of Herman's most successful newcomers have Eastern origins. "Only one area on Earth has similar climatic conditions to the Northern Plains, and that's Asia," Herman said. "This area includes southern Siberia, northern China and Russia, Mongolia, Manchuria - that region is very akin to climatic conditions here."
The beauty of Herman's varieties is they survive cold, as well as drought and heat. Their resistance to extremes makes them ideal for marketing in the "intermountain region," including Montana, Utah, Wyoming, Nevada and Colorado. So Herman promotes his trees at events like the Pro-Green Expo in Denver, where - following a three-year drought - wholesalers are clamoring for stress-resistant landscaping plants.
He educates expo audiences with a slide presentation and a three-page handout that outlines the characteristics of his introductions. His vivid descriptions belie his scientific bent: "thick, leathery, glossy foliage," "creamy-white flower panicles" and "showy, coppery-orange, peeling bark." Herman's introductions spark a lot of interest outside of the state. Few can claim so rigorous a testing ground as Herman can. "If it's hardy in North Dakota, it's undoubtedly going to be hardy west of us," he says.
To this day, the Herman farm remains a green paradise.
Although that's partly because of the increased rainfall, it's also due to the work of Herman's brother Ardon, a 1957 NDSU grad who majored in agronomy and minored in horticulture. Proving he also possesses the family green gene, Ardon started an arboretum, where Dale unofficially tests some of his varieties.
"We make a lot of comparisons," the professor says.
The Brinsmade farm has even produced a tree that found its way onto Herman's list of introductions. The Prairie Reflection Laurel Willow stemmed from a super-hero of a specimen that never developed the telltale yellow leaves of iron deficiency despite growing for nearly 100 years in high-alkaline soil.
His brother's spread is just one testing ground in Herman's well-established network. Besides a research arboretum near Absaraka, there are statewide trials at NDSU research extension centers in Minot, Dickinson, Carrington and Langdon. This allows Herman to test the same trees in a variety of soils and environments.
Herman also works with urban foresters throughout the state, a regional plant introduction station in Ames, Iowa, and national wholesale production nurseries, which propagate his new introductions.
Herman obtains most of his test specimens from asexual propagation, meaning he grows them from rooting cuttings or grafting shoots off the original tree. The result is "offspring" that are identical clones to the original.
Occasionally -- as in the case of oak trees -- propagation through traditional methods is too difficult, or too slow. In such instances, Herman turns to the laboratory of David Dai, an assistant professor of plant sciences at NDSU.
Dai can grow hundreds of future woody plants, and alter their genetics to suit various needs, through tissue cultures and other biotechnologies. A miniscule sliver of plant material is placed inside a baby food jar-sized container, where it is suspended in an aseptic, nutrient-rich gelatin. The jar is kept under grow lights and precisely monitored conditions, creating what Herman calls "a greenhouse within a greenhouse."
The samples can be modified any number of ways. Depending on the type of hormone added, the nub of vegetation will either sprout roots or Lilliputian stems and leaves. In some cases, the cells will grow willy-nilly into formless globs. Dai also can attach a new gene - be it for dwarfing, disease-resistance or some other desired trait - to the tiny plant.
When these test-tube trees grow large enough, they are transferred to artificial soil. Dai can propagate millions of woody plants in this way.
"There are only so many tissue-culture labs in the United States," Herman says. "Dr. Dai is really at the leading edge of this type of work." Such methods help expedite the introduction process, but only to a point. The whole procedure demands ample research and patience.
Research, because it can take years to evaluate how a new plant will fare against environmental factors like pests or salty soil.
And patience, because it isn't as easy to popularize new trees as one might think. The newest petunia can enjoy worldwide recognition a year after it's introduced, but people often hesitate to try out unfamiliar tree varieties. While annuals will bloom exuberantly just weeks after they're planted, trees take much longer to reap their benefits - energy conservation, increased property value and long-term landscape beauty.
"How do you get the masses to know about it, so they demand and want to buy it?" Herman says. "The propagators can't produce something if they can't sell it. You need money, full-color advertising - you have to market it. I need someone out there full time promoting our introductions." And, for the first time, he seems a bit frustrated by the magnitude of his task.
Then again, Herman has already accomplished a few amazing feats in his lifetime. Like finding birches that resist their natural enemies. Or popularizing bushes that look like September in Vermont. Or, most impressively, knowing how to make the Northern Plains a greener and brighter place.
--T. Swift
