Did You Know: Delaware's lost trees

A 1796 map shows the Great Cypress Swamp covering 50,000 acres in Delaware and Maryland with bald cypress and Atlantic cedar. No longer.

In 1895, when the peach blossom was declared Delaware's state flower, more than 800,000 peach trees in the state provided a wealthy fruit harvest. At the same time, one in every four hardwoods in Eastern forests was an American chestnut. No longer.

In 1939, when the American holly was declared Delaware's state tree, its berried branches had for decades been the nation's most important source for Christmas decorating. No longer.

Forests have been important to Delaware life for centuries. The Native Americans were the first to live in wooden homes and off the bounty gathered from the trees. The Finns who immigrated to New Sweden starting in 1638 were known as both the "forest-clearing" and "forest-destroying" Finns for their ability to quickly clear the woods by ax and fire, leaving ground ready for farming.

Until the Civil War, America's economy was "almost entirely wood-fueled," according to a Delaware Department of Agriculture exhibit prepared for the Delaware Agricultural Museum and Village. People burned wood to cook, to heat and to power equipment. Settlers from Europe and their descendants used the wood to make charcoal (critical for the DuPont Co. gunpowder business), make potash (a fertilizer made from burned trees), create barrels and other storage containers, extract tannin to make leather and build ships (until iron ships became more popular). Wood was everywhere.

But over the decades, humans, diseases, insects, fires and even plastics have dramatically changed the types of tree found in Delaware. "We do things that force changes in the environment," said State Forester Michael A. Valenti. "The forests and animals have to adapt."

Today, loblolly pine dominates Sussex County. As you head north, and environmental factors change, red maple dominates. Other important trees include red oak, black oak, hickory, Eastern white pine and yellow poplar. These are the stories of trees that used to be important.

American chestnut (Castanea dentata)

American chestnuts were "superior trees," said Lewes resident Ed Crawford, a board member of the Maryland branch of the American Chestnut Foundation. They reliably generated big annual crops of nuts (important food for wild animals, livestock and people), and their "strong, rot-resistant wood" came from trees that grew quickly to as much as eight feet in diameter and scores of feet tall.

Unfortunately, an Asian fungus called Cryphonectria parasitica, discovered in New York City in 1904, is estimated to have killed 4 billion trees in 50 years. Resilient roots will still sprout saplings that die before getting old enough to fruit and reproduce. "Functionally, they are extinct," said John Harrod, manager of the Delaware Nature Society's DuPont Environmental Education Center.

Scientists have worked for several generations hybridizing American chestnuts with the blight-resistant but smaller and less graceful Chinese chestnuts. The work intensified in 1983 with the formation of the foundation, which in 2005 produced the first potentially blight-resistant trees called Restoration chestnuts 1.0. Assisted by members and volunteers in 23 states, the organization is planting these trees in selected locations, with the Delmarva Peninsula's first chestnut education orchard announced last October at the nature society's Abbott's Mill Nature Center near Milford.

The Abbott's Mill orchard features 15 trees: American and Chinese chestnuts and three varieties of hybrids, Crawford said, adding that he is working with University of Delaware Cooperative Extension agent Dot Abbott on exploring chestnut nurseries in Georgetown and Kent County.

The American chestnut may return in a different way. In November, scientists at the State University of New York College announced that they had bred a blight-resistant American chestnut by introducing a gene from wheat. "Blight kills trees by producing oxalic acid," The Washington Post reported. "Wheat has a natural defense against oxalic acid; the plant can break it down into benign components. It turns out that a single gene is responsible for that function, and inserting that single gene into the American chestnut genome made the tree resistant."

American elm (Ulmus americana L.)

"At one time, the American elm was considered to be an ideal street tree because it was graceful, long-lived, fast growing and tolerant of compacted soils and air pollution," according to the U.S. Forest Service. Dutch elm disease, a fungus that causes the tree to wilt and die, was discovered decades ago.

"When you take a disease from one part of the world, sometimes the normal control breaks down," Valenti explained. "You have disaster."

Scattered grand elms live in Old Dover and the Westover Hills section of Wilmington, but other species have been called into duty in other areas. On the University of Delaware's Green in Newark, for example, Chinese zelkovas in the 1970s replaced the sick elms. They have the same vaselike form, "but they're much stiffer, not as graceful, not a good tree to make an allée," said UD professor Sue Barton. "It was a mistake." Since then, the university has planted resistant cultivars that weren't available when the disease first hit Delaware.

American holly (Ilex opaca)

In the 1920s and 1930s, the Sussex holly industry employed as many as 8,500 people harvesting the last crop of the season – bright red berries clustered amid thorny green leaves – that would serve as Christmas decorations. Milton "made more Christmas and holiday holly decorations than anywhere else in the world," said Allison Schell, executive director of the Milton Historical Society, giving it the nickname of "Land of Holly and Hollytown USA.

The industry, which had overcome vandals who mutilated trees that they didn't own in their haste to harvest, perished with the arrival of cheaper plastic. Hollies are still around, just not commercially as important. "But the legacy and love of real, handmade holly wreaths still lives on in Milton," Schell said. It's been marked with a December festival for 25 years.

Bald cypress (Taxodium distichum)

The Great Cypress Swamp, which crosses Sussex County and nearby Maryland along the Pocomoke River, suffered in multiple ways from human intervention. It was drained to free the land for farms. Logs that had lain for decades and perhaps centuries in the water were removed to be turned into very durable shingles. And hence the cypress and cedar that dominated the swamp and the swamp itself declined. From an estimated 50,000 acres when Europeans arrived, the swamp shrunk to 5,000 in 1929 when fires hit. They ran for so long and hit so much that the area was nicknamed the Burnt Swamp.

"They didn't understand 200 years ago what the impact would be," Valenti said of harvesting great quantities of the insect-resistant wood. "They thought it would be unlimited. They were wrong."

Since then, manufactured roofing has supplanted the cedar shakes in popularity. Government agencies and nonprofits have led efforts to restore the swampiness to the swamp and the cedars and cypresses as well. The swamp is now described as covering 13,000 acres.

Peach (Prunus persica)

Delaware was the country's leading producer of peaches for part of the 19th century, at its peak, shipping 6 million baskets to market in 1875. In the 1890s, a virus called the yellows began killing the trees. "Many peach growers lost so much money that they burned their orchards and turned the land into pastures," according to the Delaware Department of Agriculture. By 1920, only 500,000 of the state's 5 million peach trees remained.

The peach decline decimated Delaware's huge basket-building industry.

Can these trees return?

Even before humans interfered, storms, fires and other natural forces created holes in the forests, and something always took advantage of the gaps in the mosaic, even if it may not have been what was there before. "There is constant change through space and time," Valenti said of forests.

That said, "with wise management, we're going to protect what's left the best we can." About a third of Delaware's 1.2 million acres is forest, and three state agencies – Parks and Recreation, Fish and Wildlife and Forest – together manage about 110,000 acres.

"A lot of our problems in forestry come from invasive things – plants and animals," Valenti said. Examples include the fungus that attacked elms, the gypsy moths that wounded many trees and other foreign creatures that attacked defenseless native trees and foreign trees that overwhelmed natives.

"We have to be careful about what we introduce," he said. "What if it has a bug that will kill all of our trees? Consider the emerald ash borer. Eventually, it will come to Delaware, and that insect will find and kill our ash trees."

Sometimes, plants can recover. Barton offered a hopeful story that she learned from Doug Tallamy, another UD professor, involving the disappearance of the atala butterfly from Florida. As the state urbanized and its native plants were cut down, atalas were considered extinct. But when an old-fashioned plant called a coontie became fashionable, atalas were spotted again – an interesting observation since the coontie was the sole host for atala larvae. "If we can do that by mistake," she said, "think what we can do more purposefully."

Also in trouble

• Blackjack oak (Quercus marilandica): Fire-dependent species of the coastal plain, now scarce due to fire suppression, according to Harrod.

• Butternut (Juglans cinerea): Piedmont species that is declining throughout its range due to a disease/blight.

• Red oak, facing anthracnose and bacterial leaf scorch.

• Shortleaf pine (Pinus echinata): Now scarce due to land clearing and inability to compete with aggressive colonizers such as Virginia pine and loblolly pine.

• The ash is threatened by the emerald ash borer, already attacking the forests in Pennsylvania and Maryland.

• The dogwood (Cornus florida) is struggling against powdery mildew and anthracnose.