The dead elm tree removed from the yard a short time ago was Harvard's latest concession to a disease which threatens to deracinate all of New England's staeliest shade trees. Since its discovery in Massachusetts in 1941, Dutch Elm Disease has killed a recorded 50,000 of the state's American elms, and probably as many more died unnoticed or unrecorded.
The really disturbing thing about the disease is that it chooses to kill trees which give New England's countryside much of the beauty people find in it. Towns like Concord, which has lost 130 trees in the last three years, and Lexington, which has lost nearly 400, are beginning to look ragged and motheaten without their once plentiful elms; and they will eventually look nude, for there is no cure for Dutch Elm Disease.
Named after the Dutch pathologist who first described it, the disease is caused by a fungus, Ceratostomella ulmi, which is introduced into the trees by an unattractive European elm bark beetle, Scolytus multistriatus. Toxins and gummosis produced by the fungus in the tree's water-conducting vessels may kill it in six months. Once disease is detected, death may be retarded, somewhat as in cancer, by removing more and more of the affected parts. Widespread use of preventative measures, such as burning old or dying trees to kill the beetles, or spraying and feeding the trees to discourage inhabitation, have proved only partially effective. Many towns cannot afford to keep constant watch over hundreds of trees to prune thousands of broken or dead limbs which are prospective housing developments for S. multistriatus.
The disease has a rather exotic origin; it apparently began somewhere in the Far East, and travelling West, enjoyed moderate success with European varieties of elm. It was not until 1919, however, that Cerastomella really caught hold; beetles carried to this country on elm logs to be used for furniture veneer somehow escaped, and carried the fungus to the Elysian Fields of Unius americana. Travelling up the Connecticut River Valley into New England, and westward as far as the Mississippi, the beetle-fungus team has outrun its pursuers, cutting a determined swath which pathologists estimate will exterminate most of the genus in another ten or twenty years.
The Buildings and Grounds Department is waging a losing fight to save the University's elms. Although many other varieties shade University property, several areas, particularly as the Yard, are populated mostly with the susceptible species. Rather than replant new elms, which live two or three hundred years, the department is filling gaps with faster-growing maples, pines, and pin oaks. These are respectable shade trees; but they are not elms, which is rather sad.