Trees have been aesthetically important to people since earliest civilization. Egyptians, Phoenicians, Persians, Greeks, Chinese and Romans held trees in high esteem.They valued trees for their aesthetic benefits as well as developing formal gardens and sacred groves.
During the late 1700s in Philadelphia there were no street trees.In the mid-1800s, tree-lined boulevards were first introduced in Paris.Insurance companies in the United States would not insure houses that had trees in front of them.
The Lombardy polar, Norway maple, English elm, and Ailanthus were new tree species that were introduced in North America during the late 1700s and 1800s. Most of the early trained horticulturalists and foresters were of European origin, thus the planting of European stock persisted until the 1900s.
By the mid-1800s, Andrew Jackson Downing was a leader in the movement to use native North American species instead of exotic species. Especially fond of the native maples, oaks, and elms for city tree plantings, his influence can still be found in many cities established before 1850. The concept of landscaping in the United States grew as a result of the work Andrew Jackson Downing, Calvert Vaux, and Frederick Olmestead did on designing parks as well as the increasing industrialization during the mid-1800s.
In 1924, the International Shade Tree Conference (now International Society of Arboriculture)(link to their listing on the Green Resources page), began. It was the first organizational effort to respond to public concern for planting and care of lawn and street trees in the urban landscape.
“Ceratoyaystis ulmi,” defined as cancer, is a fungus spread by a tiny elm bark beetle and root graphs. DED, commonly known as Dutch Elm Disease, is a fungus that moves into the water.DED invades vessels of the elm, clogging the flow of water and nutrients to the tree.
Dutch Elm Disease was first found in Holland in 1921. It was recognized in dying elms over central and southern Europe. It hit America via the port of Cleveland, Ohio, on wooden crates made with infected elm wood in the early 1930s.
Scientists believe the fungus came from the Himalayas and traveled from Europe to the Dutch Indies in the late 1800s. By 1945, Sorel, Quebec was the second city effected by the disease. It subsequently destroyed over half the remaining elm trees in Eastern Canada and the US.
In 1950, Syracuse, New York, had 53,000 elms along its streets. Today it has fewer than 300 as a result of the ravages of Dutch Elm Disease. By the 1960s, 17 million of the country’s 23 million elm trees were dead.
Dutch Elm Disease destroyed millions of elms dating back to the 1700s.
Once the most popular and important shade tree in this country, the American elm is the most susceptible elm species while the Siberian and Chinese elm are quite resistant.
In 1932 the disease hit New Jersey, New York, Connecticut, and Maryland. Between 1933 and 1947 the federal government spent $25 million in an unsuccessful attempt to wipe out the disease.
By 1955, the first case of DED occurred on the East Side of Milwaukee and eliminated much of the tree canopy in the city. 128,000 Elm trees lived on Milwaukee streets in 1950 while only 6,000 remain today.
Urban Forestry Management
By the 1700s, the use of trees in urban setting, knowledge of growth and maintenance, and respect for their importance, was increasingly recognized. By 1872, J. Sterling Morton proposed an annual Arbor Day.
The concept of urban forestry or total management of the urban forest system did not develop until the mid-1960s. Pressures for such management came early in the 1950s as a result of DED, oak wilt, and phloem necrosis.
In 1965, urban forestry was first introduced as a field of study at the University of Toronto. Urban forestry includes public and privately owned trees directly managed by city government in and around urban areas.
Two forms of management have developed. One is done for the forest to maintain health and vigor and the second is done to the forest to prevent undue interference with trappings of society, (power lines, roadways, etc.).
The management of publicly and privately owned trees in and adjacent to urban areas covers a wide scope: city greenbelts, streets, utility right of ways, city parks, street trees, seashores, riverfronts, residential, commercial and industrial property, highways and railroad rights of ways, public buildings and grounds, and even individual garden trees.
Maintenance involves all practices between planting and removal, such as growth control, damage control, and insect disease control. One of the most important management practices within the urban forest is pruning
For a summary of the Urban Ecological Analysis of Milwaukee performed by American Forests, click here.
For more information about urban forests, click here.